Your FREE ASE T5 Suspension and Steering Practice Test 2026 – 150+ Q&A

Correct answer: Tight column splines

Correct answer: Tight column splines. Binding inside the steering column shaft is what stops the wheel from coasting back to center once the driver releases it, so return is sluggish rather than absent. Worn gearbox sectors produce free play on-center, not resistance to returning. Low hydraulic volume raises effort while the driver is turning and does not hold the wheel off center afterwards. Excess tire pressure shrinks the contact patch and reduces scrub, which would speed return up.

Correct answer: Sector shaft gearbox

Correct answer: Sector shaft gearbox. Lash between the worm and the sector shaft inside the gearbox is the usual source of excessive lost motion at the wheel, and it is both adjustable and quick to verify, so it is checked first. Outer linkage joints are checked after the gearbox, once lash there has been ruled out. An upper column coupler rarely wears enough to give measurable lost motion. A pump rotor governs assist pressure and contributes no lost motion at all.

Correct answer: Depleted fluid reserves

Correct answer: Depleted fluid reserves. A low level starves the pump, so hydraulic assist falls away and effort climbs at every road speed rather than only at one. Restricted supply hoses would show up most sharply at high flow, during rapid turns. Damaged gearbox sectors give roughness and lost motion instead of a uniform rise in effort. A shorted pressure switch reports a value to the electronics and does not itself throttle the assist the driver feels.

Correct answer: Ambient air infiltration

Correct answer: Ambient air infiltration. Foam is entrained air, and air reaches the circuit through a loose fitting, a porous hose or a suction line drawing below the fluid level. Water contaminated fluid turns milky and cloudy but does not whip up into foam. A defective pump cartridge makes noise and loses pressure while leaving the fluid clear. Progressive gearbox wear adds lash and metallic debris, neither of which aerates the fluid.

Correct answer: Defective control valve

Correct answer: Defective control valve. Only the control valve treats the two directions separately, so a fault inside it can starve one side of the piston while the other side still receives full flow. A corroded linkage socket adds friction in both directions equally. A reduced reservoir level and a weakened pump cartridge both cut assist everywhere, so the wheel would feel heavy turning either way rather than in one direction alone.

Correct answer: Sticky gearbox valve

Correct answer: Sticky gearbox valve. The valve inside the gear meters pressure to each side of the piston, so a spool that sticks or leaks across one land gives full assist one way and reduced assist the other. Uneven tire pressure changes rolling resistance, not hydraulic assist. Worn column bearings loosen the shaft without altering pressure. Angle sensors feed the electronics and have no authority over hydraulic flow in either direction.

Correct answer: Trapped system air

Correct answer: Trapped system air. Opening the circuit lets air in, and the bubbles that remain after refilling collapse as they pass through the pump, which is heard as a whine until the circuit is bled. A defective new pump is possible but far less common than air after a fresh install. An improper oil grade alters effort and temperature rather than producing a noise that fades with bleeding. Tight belt tension loads the bearing and squeals or rumbles instead.

Correct answer: Left front brake caliper

Correct answer: Left front brake caliper. Once geometry has been corrected and the truck still tracks toward one side, a brake that does not fully release on that side is the next thing to check, because the residual drag acts exactly like a steering input. A sector gearbox worm gear adds lost motion, not a steady side force. An assist pump drive pulley governs flow to both sides equally. A rear left spring shackle alters ride height rather than front-wheel tracking.

Correct answer: Wheel hub bearings

Correct answer: Wheel hub bearings. Once lash in the linkage and the gear has been eliminated, the remaining place lost motion can hide is the hub, where excess end play lets the wheel tilt and shows up at the rim as further free play. Frame rail flexure is a structural fault that would be obvious as cracking rather than as play. A steering axle beam is a rigid forging and does not develop play on its own. Rear spring bushes are too far from the steered wheels to register at the rim.

Correct answer: Steering-gear sector mesh preload

Steering-gear sector mesh preload is the improper setting behind high steering effort, because an over-tight sector mesh loads the gear and the driver has to overcome that drag at the wheel. An improper kingpin bore inclination changes returnability and scrub radius rather than the effort needed to turn the gear. Front-axle camber angle tolerance shows up as tire wear and pull, and steering knuckle toe-out geometry governs how the wheels track through a turn.

Correct answer: Worn steering linkage sockets

Worn steering linkage sockets are the most likely cause: lost motion in the drag link and tie rod ball sockets lets the steer wheels drift before the driver's input reaches them, so the truck will not hold a lane. Overinflated steer axle tires harshen the ride and wear the tread center without adding lost motion. A defective power steering pump cuts assist and makes the steering heavy rather than vague, and incorrect rear axle alignment makes the truck dog-track down the road on a steady heading.

Correct answer: It couples the two knuckles so the steer wheels turn alike

The cross tube couples the two knuckles so the steer wheels turn alike, which is also how the toe setting is held across the axle. It does not support the axle weight so the road shock stays damped — the springs and shock absorbers do that. Nothing feeds the engine torque so the front wheels stay driven on a conventional truck, whose steer axle is not driven at all. And the part that joins the sector shaft so the steering arm gains motion is the drag link, not the tie rod.

Correct answer: It converts the shaft rotation so the drag link moves endwise

The pitman arm converts the shaft rotation so the drag link moves endwise: it splines onto the sector shaft, and as that shaft turns the arm swings, pushing or pulling the drag link to steer the axle. It is not what absorbs the road shocks so the steering linkage feels calm — that is the steering damper. It does not hold the roller preload so the knuckle spindle stays cool, which is a wheel bearing adjustment, and it never pumps the hydraulic fluid so the steering box gains assist, which is the power steering pump's work.

Correct answer: The pivot member that swivels the kingpin bore and carries the wheel spindle

The knuckle is the pivot member that swivels the kingpin bore and carries the wheel spindle, so the hub and brake ride on it while it pivots on the kingpin pressed into the axle beam end. The threaded sleeve that adjusts toe is part of the tie rod cross tube. The socket assembly terminating the drag linkage is a ball-and-socket joint, and the flexible joint at the steering shaft is the shaft U-joint.

Correct answer: It builds the oil flow and pressure that the gear valve meters

The power steering pump builds the oil flow and pressure that the gear valve meters, and that metered pressure is what eases driver effort at the wheel. Regulating ride height and stance for the air bags is the leveling valve's job. Reading wheel angle for a control module belongs to an electronic system, and nothing on a conventional truck stores a charge to steer a dead motor.

Correct answer: To absorb the road shock and shimmy in the front linkage

A steering stabilizer is there to absorb the road shock and shimmy in the front linkage, mounted much like a shock absorber between the axle and a steering component. It is not there to govern the wheel lash and travel in the federal range, which is a gear and linkage condition measured against the diameter table. It does not provide the return force and bias in the steer wheels, since caster and steering geometry do that, and it cannot boost the hydraulic assist and flow in the slow range, which the pump and gear supply.

Correct answer: 2 1/2 in.

For a 20-inch wheel the maximum allowable lash is 2 1/2 in. The federal inspection criteria for vehicles over 10,000 lb GVWR scale free play with rim diameter: 2 inches up to a 16-inch wheel, 2 1/4 inches at 18 inches, 2 1/2 inches at 20 inches and 2 3/4 inches at 22 inches. So 1 1/2 inches and 2 1/4 inches are tighter than this wheel has to be held, and 2 3/4 inches belongs to the larger 22-inch wheel. The check is made by rotating the rim until the front wheels just start to move.

Correct answer: Turn the loaded rim and measure the arc that precedes tire movement

The correct method is to turn the loaded rim and measure the arc that precedes tire movement: the wheels stay on the ground and pointed straight, the rim is turned each way until the tires just begin to move, and the travel between those points is the lash compared to the diameter-based limit. Unbolting the drag link to gauge sector motion measures gear lash alone and ignores the linkage. Lifting the axle to rock a wheel checks bearing and kingpin play, and applying a set torque to read deflection is not how free play is specified.

Correct answer: Technician A is right, B is accurate

Technician A is right and B is accurate, because excessive free play is additive across the system. Worn tie rod and drag link ball sockets add lost motion in the linkage, and worn or maladjusted over-center lash adds lost motion at the gear, so each source has to be measured on its own. Calling B mistaken ignores the gear's contribution, calling A wrong ignores the linkage's, and the reading that both men are wrong contradicts the way total lash is built up.

Correct answer: Worn kingpins and loose linkage sockets with the dead damper

The likely root cause is worn kingpins and loose linkage sockets with the dead damper. Death wobble is a resonant oscillation set off by a bump: play in the kingpins and steering joints lets the wheels shimmy, and a damper that no longer absorbs that energy lets the shake sustain itself. Aerated fluid and glazed pump belts with a loose reservoir cut assist instead of starting an oscillation. Cupped tires on stiff spring bushings with fresh shocks describe a harsh ride, and a topped gearbox with balanced radial tires lists conditions that are in good order.

Correct answer: The drag link reaches the pitman arm, while the tie rod spans the knuckles

The difference is that the drag link reaches the pitman arm, while the tie rod spans the knuckles. The drag link carries steering motion from the gear through the pitman arm to one knuckle, and the cross tube then ties both wheels so they turn together and holds the toe setting. Neither part is hydraulically actuated, so nothing here takes a hydraulic feed. Toe is set at the tie rod rather than the drag link, and the two are separate parts, not one part under two shop names.

Correct answer: Excessive sector-shaft mesh lash in the steering gear

Excessive sector-shaft mesh lash in the steering gear is the one to rule out: too much lash makes the gear feel loose and adds free play, and looseness is the opposite complaint from high effort. A loose polished belt pulley in the accessory driveline lets the pump slip so assist falls off. Contaminated scored rotor vanes cut the pump's output directly, and a chronically low fluid level starves it, so each of those three does produce hard steering.

Correct answer: Take the worm preload first, then the centered mesh in inch-pound drag at the input

The right method is to take the worm preload first, then the centered mesh in inch-pound drag at the input. Worm bearing preload has to be right before over-center lash is set, over-center is checked with the gear on its high point where mesh is tightest, and what is measured is rotating drag in inch-pounds at the input shaft. You do not release the clamp nut first, then the sector screw in complete reverse at the limit, because running the adjuster out strips the mesh instead of setting it. The gear is adjustable, so you do not shorten the drag linkage first, then the tie rod in single increments at the clamps. And to turn the sector lash first, then the worm bearings in foot-pound pull at the pitman reverses the order and reads the wrong scale in the wrong place.

Correct answer: Technician A is sound, B is justified

Technician A is sound and B is justified. The over-center adjustment is made with the gear centered because the ball nut and sector are cut so that mesh is tightest at the high point, which is where lash has to be measured and set. Running the adjuster in until every trace of play disappears binds the gear, raises effort and destroys return-to-center, so it is set to a specified inch-pound drag instead. Calling A shaky ignores the high-point design, and calling B misguided ignores what over-tightening does to the gear.

Correct answer: Loose steering sockets and slack kingpin bushings

The most likely finding is loose steering sockets and slack kingpin bushings: slop in the ball sockets and kingpin bores lets the steer wheels move before the driver's input reaches them, so the truck will not track straight. Overtight sector-shaft lash and stiffer gear mesh cause heavy effort and poor return rather than wander. Renewed steering sockets at factory stud torques are exactly what a sound truck has, and raised steering pressure with settled valve limits changes assist, not directional stability.

Correct answer: Grip the unloaded joint and watch the stud shank for relative motion

The correct check is to grip the unloaded joint and watch the stud shank for relative motion: with weight off the tire or a helper rocking the wheel, felt play at the stud, or a split boot, condemns the joint. To span the crosstube barrel and note the caliper jaws for actual width measures tube diameter, which says nothing about joint wear. A tie rod end carries no hydraulic pressure, so you cannot tap the linkage fitting and read the gauge needle for fluid pressure, and to spin the raised wheel and judge the bearing rumble for audible whine is a bearing test instead.

Correct answer: Unbalanced eccentric steer tires with worn linkage joints

The likely cause is unbalanced eccentric steer tires with worn linkage joints. Shimmy is a forced vibration that peaks near a resonant speed: imbalance or radial runout in the steer tires excites it, and looseness in the tie rods, drag link or kingpins lets the oscillation build. An overcharged dryer cartridge with a damp tank line belongs to the air system. Slack battery holddown brackets rattle without steering anything, and slightly high assist pressure on fresh tie-rod bushings cannot set up a speed-specific oscillation.

Correct answer: Dropped reservoir volume or aerated frothy oil

The likely cause is dropped reservoir volume or aerated frothy oil. A whine that is loudest in low-speed turns and at full lock is classic pump cavitation: the pump runs short of oil or draws air in, foams it, and gets noisy under the heaviest demand. A filled container of purged stable fluid describes a healthy system rather than a fault. Slackened wheel fasteners produce a clunk instead of a whine, and hardened steer casings with scrubbed tread change ride and wear.

Correct answer: Technician A is backed, B is supported

Technician A is backed and B is supported. A restricted suction hose starves the pump inlet so it cavitates and whines, and aerated foamy fluid from a low level, or air pulled past a loose return-line clamp, does exactly the same thing. Both faults put air or vapor into the pump, so diagnosing a whine means checking inlet restriction, fluid level and the return side for air ingestion. Calling A flawed discards the inlet path, and calling B unfounded discards the aeration path.

Correct answer: Plumb the analyzer inline and match the measured pressure and flow to the chart

The right way is to plumb the analyzer inline and match the measured pressure and flow to the chart: the gauge and its load valve go into the pressure line, the valve is closed slowly to read maximum relief pressure, and flow is read at idle and at raised rpm, then both figures are set against the manufacturer's numbers. To rotate the steering wheel and compare the counted lash and travel to the limits measures linkage and gear lash, not pump output. To inspect the accessory belt and trust the outward tension and surface to the eye proves nothing about what the pump delivers, and to replace the suspect unit and prove the fitted repair and outcome to the highway is parts-swapping rather than diagnosis.

Correct answer: Technician A is valid, B is precise

Technician A is valid and B is precise. A pitman arm loose on the sector shaft splines, or a worn pitman-to-drag-link ball socket, gives a clunk over bumps and feeds wander. Those same faults add lost motion to total steering free play, so the linkage has to be repaired before any gear over-center adjustment, or the gear gets misadjusted to mask linkage wear. Calling A wrong denies the clunk a source, and calling B inexact would have the gear set over uncorrected slop.

Correct answer: Worn kingpins and loose bushings

With the wheel bearings confirmed in adjustment, vertical play felt when the tire is rocked top to bottom points to worn kingpins and loose bushings. Clearance between the kingpin and its bushings in the steering knuckle also explains the tight, notchy feel and the poor return to center. Split hoses and damaged fittings would reduce assist without creating any vertical play, hard tires and swollen sidewalls change ride quality rather than knuckle clearance, and sloppy arms and battered splines put the looseness in the steering-wheel-to-gear path instead of top and bottom at the knuckle.

Correct answer: The pump relief valve that unloads the pressure once the wheels reach the stops

The behavior is best explained by the pump relief valve that unloads the pressure once the wheels reach the stops. Holding the wheels hard against the stops dead-heads the flow, system pressure climbs to the relief setting, and the valve opens so the pump groans momentarily as it unloads. That is normal high-load behavior confined to full lock. The column shaft coupler that stiffens up solid would make the steering heavy everywhere rather than only at lock, the gear overcenter screw that pinches up tight changes on-center feel instead, and the drag link ball socket that generates vapors is impossible because a mechanical linkage joint carries no hydraulic fluid.

Correct answer: The column intermediate shaft joints and its splined slide coupler

With the gear, linkage and front-end joints already confirmed tight, the next place to look is the column intermediate shaft joints and its splined slide coupler, where worn universal joints or a loose splined slip fit create lost motion and clunk between the steering wheel and the gear input shaft. The reservoir filler cap gasket and its pressure relief diaphragms have no mechanical path to steering free play, the forward shock absorber joints and its rubber isolator cushions affect ride rather than steering feel, and the brake chamber pushrod extension and its slack adjuster linkage belong to the foundation brake.

Correct answer: A worn-down pump or a porous internal valve, so the test gauge sits below rated relief pressure

The result indicates a worn-down pump or a porous internal valve, so the test gauge sits below rated relief pressure. With the tester load valve shut the pump is dead-headed and should climb to its rated relief setting; when it cannot, the pump is internally worn or the relief valve is leaking past. The stem states the load valve was fully closed, which rules out a tester pump valve blocked or wedged apart; a tight or firm overcenter gear adjust bolt is a mechanical adjustment that cannot limit pump output; and a bent pitman arm or cracked sector splines have no effect on hydraulic pressure. The load valve must never be held shut more than a few seconds.

Correct answer: A choked or dud power steering cooler that overheats the oil

The most likely cause is a choked or dud power steering cooler that overheats the oil. Sustained low-speed, tight-radius steering drives a great deal of heat into the fluid; when the cooler is plugged or not flowing, the oil overheats, darkens, thins out, and assist fades until the truck cools, which matches the heat-dependent symptom exactly. A stiff or gritty power steering column that binds the shaft would feel heavy from the first mile of the shift, a wide or slim power steering wheel that alters the leverage is a fixed effect that never changes with temperature, and a slack or parched power steering pulley that slips the belt would squeal and lose assist straight away rather than only when hot.

Correct answer: The bypass valve venting at a set design ceiling

The most likely cause is the bypass valve venting at a set design ceiling. Holding the front wheels hard against the stops dead-heads the system, pressure climbs to the pump's pressure-limiting setting, and the valve opens exactly as it was designed to so the pump is protected; that momentarily raises steering effort and can groan, then everything is normal again. The sector output seal weeping at a grooved bore would bleed assist away all the time, the air pocket churning at a trapped line corner would make the steering foamy and noisy at every lock, and the pitman arm spline slipping at a stripped hub would give lost motion rather than lost assist.

Correct answer: Steering axle kingpins

Correct answer: Steering axle kingpins. Worn or badly adjusted kingpins let the knuckle tip and wander, which throws the camber and toe of the steer wheels out and scrubs the tread unevenly, so they head the inspection list on a heavy truck. Hydraulic damper units influence ride control and show cupping only on lighter chassis. Wheel spindle bearings give noise and play long before they mark the tread. Rubber spring bushings shift axle position slightly but rarely enough to scrub a tire.

Correct answer: Fatigued cracked leaves

Correct answer: Fatigued cracked leaves. A spring that has lost its arch has lost its set, which happens when individual leaves crack or fatigue and can no longer carry their share of the load. Sustained axle overload is a contributing history, but a sound spring recovers its arch once the load comes off, so the flat profile still points to the leaves themselves. Seized shackle bushings restrict travel without flattening the stack. Blown damper cartridges affect oscillation control only.

Correct answer: Affected corner bag leakage

Correct answer: Affected corner bag leakage. A bellows that loses air cannot hold its share of the load, so that corner settles while the rest of the chassis stays up. A defective ride height valve would normally throw the whole axle out of level, not one corner. An uneven pallet weight spread compresses the loaded corner but leaves the bellows pressure correct, and the system would correct for it. Worn spring hanger bushings allow movement without changing static height.

Correct answer: Improper hookup practice

Correct answer: Improper hookup practice. Jaws are cut to close fully around the pin, and they only wear abnormally when they are repeatedly slammed, half-latched or dragged across the pin during hookup. Excessive grease buildup reduces friction on the plate and protects the jaws rather than wearing them. A misaligned turntable top marks the bearing face and the pin, not the jaw faces. A deformed trailer kingpin is itself usually the result of bad hookups rather than the origin of the jaw wear.

Correct answer: Exhausted shock dampers

Correct answer: Exhausted shock dampers. Dampers exist to restrain the weight transfer that a brake application causes, so once they lose their valving resistance the truck's rear end dips sharply as the brakes take hold. A faulty bellows assembly changes static height rather than the speed of the dip. Fractured spring leaves sag continuously rather than only during braking. An overcharged ride system sits high and rides hard, which resists pitch instead of exaggerating it.

Correct answer: Worn pivot bushings

Correct answer: Worn pivot bushings. The bushings carry the rocking motion of the top plate, so once they are worn the plate can shift lengthwise under acceleration and braking, which is felt as fore-and-aft slop. Loose bracket bolts let the whole unit move on the rails, which reads as a shifting mount rather than play within the coupler. A scored deck surface affects trailer plate wear only. An excess grease layer masks noise but adds no measurable travel.

Correct answer: Vehicle payload overload

Correct answer: Vehicle payload overload. Rails are sized for a rated load, and carrying more than that puts the structure past its elastic limit so it takes a permanent set that shows as twist. Frequent tight maneuvers stress the coupler and the tires rather than the rails. Excessive offroad speeds punish the suspension and mounts but rarely deform a correctly loaded frame. Ordinary service fatigue produces cracks at stress risers instead of a wholesale change in frame shape.

Correct answer: Chassis height valve

Correct answer: Chassis height valve. The valve is what meters air in and out to hold a set trim, so an unloaded chassis that settles at one end points straight at the valve or its linkage. Rear shock absorbers control motion and carry no static load, so they cannot lower the chassis. Front spring hangers would have to be badly damaged to change trim, and that would be visible. Tandem bellows units are a possible leak path, but the valve governs them and is checked first.

Correct answer: Defective damper units

Correct answer: Defective damper units. Springs store the energy that driving over bumps puts into a heavy-duty truck and the dampers dissipate it, so once the damping is gone the body keeps bouncing long after the bump has passed. Loose shackle bushings add clunks and lateral movement, not sustained bounce. Misaligned front axles scrub tires and spoil tracking. Elevated tire pressure makes the ride sharp and jittery over small inputs rather than allowing a slow, repeated rise and fall.

Correct answer: Height control valve

Correct answer: Height control valve. That valve is the only device that decides how much air the bags hold at any moment, so pressure that will not settle is its responsibility until proven otherwise. Compressor feed rate governs reservoir supply, and a shortfall there would drop system pressure across the whole truck. Air line connections leak steadily rather than allowing pressure to wander up and down. Dryer purge function affects moisture and contamination, not the set point.

Correct answer: Perforated corner bellows

Correct answer: Perforated corner bellows. A bellows with a split or a chafed spot cannot hold its share of the load, so that corner sits down while the rest of the chassis stays at trim, which reads as a lean. Asymmetrically worn tires alter height by a few millimeters at most. A collapsed opposite damper permits movement but carries no static load. Misaligned rearward axles change how the truck tracks and how it wears its tires, not how level it stands.

Correct answer: Excessive lateral turn loads

Correct answer: Excessive lateral turn loads. Hard cornering with a loaded trailer feeds a large side force through the coupler into the mounting hardware, and that repeated side loading is what starts cracks around the fasteners. Overtorqued deck mount bolts stretch or snap the fasteners themselves instead of splitting the surrounding metal. Advanced top plate corrosion thins the bearing face, away from the bolt holes. Gradual road service fatigue alone should not crack correctly rated mounts.

Correct answer: Engine driven compressor

Correct answer: Engine driven compressor. Nothing downstream can build pressure the compressor never made, so when the system will not reach its target the unit that generates the air is verified first. Bellows assembly leakage is checked afterwards, once the supply side is known to be good. Supply line obstructions slow the fill of one circuit rather than capping overall pressure. Protection valve springs decide the order in which circuits fill and cannot hold the whole system low.

Correct answer: Seized shock dampers

Correct answer: Seized shock dampers. A damper whose valving has jammed cannot stroke, so the suspension is effectively locked and every road irregularity is fed straight into the chassis as harshness. Worn radius bushings loosen axle location and produce noise and wander rather than a rigid ride. Overfilled ride bags are corrected automatically by the height valve. Damaged leaf springs sag or rattle, and a weakened spring generally softens the ride instead of hardening it.

Correct answer: Repeated chassis overload

Correct answer: Repeated chassis overload. Loads beyond the rating force the stack to flatten further than it was designed to, which drives the leaves against one another and grinds them unevenly. Dried interleaf lubricant increases friction but wears the contact faces evenly along their length. Incorrect axle squareness scrubs the tires and twists the spring seats rather than abrading the leaves. Severely corroded hangers attack the mounting points, not the leaf faces themselves.

Correct answer: Faulty leveling valve unit

Correct answer: Faulty leveling valve unit. The leveling valve, also called the height control valve, is the one device in an air suspension system that senses trim and admits or exhausts air to hold it, so a truck that fails to maintain the correct ride height points there first. Aged rubber spring bellows harden and crack, but a sound bag still holds whatever pressure the valve sends it. Leaking supply line unions and a weak engine air compressor both starve the whole vehicle of air rather than upsetting one axle's set point.

Correct answer: Bracket bolt torque

Correct answer: Bracket bolt torque. Movement that appears only under load is usually the whole assembly shifting on its rails, and confirming the fasteners are tightened to specification is quick, cheap and rules out the most common cause before anything is dismantled. Jaw latch mechanism wear shows up as play against the trailer pin, which is felt without load. Pivot pin clearance is checked after the mounting has been proven tight. Deck surface grease governs friction, never movement of the mount.

Correct answer: Lateral play exceeds the wear limit, and the kingpin bushings face renewal

The conclusion is that lateral play exceeds the wear limit, and the kingpin bushings face renewal. Industry guidance calls for replacement once side-to-side movement at the wheel reaches roughly one eighth of an inch, about 0.120, and a reading of 0.135 is past that. Saying overall play fits the standard limit, and that the kingpin bushings stay usable, contradicts the measurement itself. Dial figures do not require the stripped wheel, because the check is made with the wheel on and the weight off the tire. And vertical lift does not outrank the flat sweep so that the sideways count means little — the side-to-side sweep is the measurement this test exists to take.

Correct answer: Upward knuckle lift with weak return bias

Upward knuckle lift with weak return bias best supports worn kingpins. Worn bushings let the knuckle rise on the axle eye when the tire is pried up with a dial indicator resting on the knuckle, and the lost pivot geometry shows up as poor return-to-center. Excessive rim lash with steady tread wear fits a gear or linkage fault just as well, so it does not separate the two. Foamy assist fluid and a greasy pump casing both point at the hydraulic side rather than the kingpin joint.

Correct answer: Technician A is factual, B is misplaced

Technician A is factual and B is misplaced. A kingpin is the steering pivot joining the knuckle to a solid I-beam axle, filling the same functional role that ball joints fill on an independent suspension, so the comparison A draws holds. The two are not interchangeable parts, though: a ball joint cannot be dropped into an axle and knuckle machined for a kingpin, so calling B warranted endorses a swap that will not fit, and calling A invalid denies a sound analogy.

Correct answer: A curved steel strip stack that supports the loaded chassis weight

A leaf spring is a curved steel strip stack that supports the loaded chassis weight. The leaves are clamped together and hung from the frame at a fixed hanger and a shackle, so they flex under load and cushion road shock. A rubber air-filled bellows unit describes an air spring. A sealed oil-filled shock damper describes a shock absorber, and a coiled steel torsion shaft describes a torsion bar.

Correct answer: To damp the rebound motion of the springs

A shock absorber exists to damp the rebound motion of the springs, converting suspension movement into heat so the spring stops cycling after a bump. Carrying the parked weight of the chassis is the spring's own task, not the damper's. The laden height of the tractor is fixed by spring rate or a height-control valve, and resisting the sideways thrust of the axle belongs to a track bar or torque rod.

Correct answer: Worn, ineffective shock absorbers

Worn, ineffective shock absorbers explain both findings: once a damper stops resisting fluid flow the spring keeps cycling, so the truck bounces repeatedly and the tire skips against the road to leave a scalloped cup pattern. Stiff, overinflated front radials harshen the ride but do not sustain oscillation after the bump has passed. Loose, slackened U-bolt fasteners let the axle wander and knock rather than bounce, and a cracked, rusted frame crossmember produces neither sustained cycling nor cupping.

Correct answer: That cool unit lost damper action and needs quick renewal

The evidence says that cool unit lost damper action and needs quick renewal. A damper that is doing work turns motion into heat, so a unit that stays cold while its neighbors warm up, and that strokes with almost no resistance, is no longer converting energy. It cannot be resisting strong loads and throwing extra heat, because it is the coldest one on the truck. It is not creating steady force either, and the warm units are the ones behaving correctly, so they are not the faulty ones.

Correct answer: A link that keeps axle alignment and blocks driveline twist

A torque rod is a link that keeps axle alignment and blocks driveline twist, holding the axle square under the frame during acceleration, braking and cornering; transverse versions also keep it centered side to side. It is not a collar that adjusts steer travel and damps wheel kickback, which describes a steering component. It is not a crossbar that joins leaf springs and spreads chassis load, and it is not a device that reports clamp force and flags loose fasteners, which describes a measuring instrument.

Correct answer: Replace the worn bushings and recover the lost alignment

The right conclusion is to replace the worn bushings and recover the lost alignment. Rubber that has cracked and pulled away from its metal sleeve lets the rod change length under load, so the axle shifts, the reset alignment drifts straight back out, and the loose joint knocks. Crediting the leaf springs and labeling the bushings blameless is wrong because the rods, not the springs alone, hold axle position on this suspension. Ignoring the broken bushings and resetting the tandem geometry only repeats a correction that will not hold, and accepting the steady thumps treats a genuine defect as if it were designed in.

Correct answer: A setup that inflates rubber bags to handle loads and hold height

Air suspension is a setup that inflates rubber bags to handle loads and hold height: compressed air inside the bags carries the load, and a height-control valve admits or vents air so the frame rides at the same level empty or loaded. Nothing in the system channels engine vacuum to cushion jolts and cut sway; the medium is shop air from the compressor, not manifold vacuum. It does not merely mount liquid dampers and skip springs, because dampers control motion but cannot hold the chassis up, and it is not a stack of steel leaves that forgoes shocks, which describes the leaf-spring design it replaces.

Correct answer: Park the truck level and inflated, then match the spec and reset the height linkage

The correct sequence is to park the truck level and inflated, then match the spec and reset the height linkage. Ride height is only meaningful with the bags carrying the chassis on level ground, and the published figure is brought into range at the height-control valve linkage. Stripping the truck empty and hoisted so the bags can be pulled destroys the very dimension being measured, and raising the truck clear and drained does the same by unloading the springs. Counting the threads and adjusting the height screw on a loaded, idle truck substitutes a thread count for the manufacturer's dimension, which is not how the valve is set.

Correct answer: The rubber bag has split and needs replacement

Steady bubbling under a soap test at the bag and its base plate shows the rubber bag has split and needs replacement; escaping air is what raises the film into bubbles, and a bag that will not hold pressure lets that corner settle at rest. A frame member that has cracked cannot leak air, and a corner damper that has failed changes ride quality without losing pressure. An air valve that has drifted would hold the whole corner at the wrong height without producing localized bubbles at the bag itself.

Correct answer: Charge the whole system and soap the joints for leaks

The first move is to charge the whole system and soap the joints for leaks. A chassis that settles overnight and comes back up when driven is losing pressure faster than it gains it while parked, and the running compressor hides that on the road, so the job is to find where the air escapes — fittings, valve bodies and the bags themselves. Realigning the loaded axle and squaring the wheels for toe treats a tire-wear complaint that was never made. Renewing the rubber bags and skipping the search for trouble replaces parts before the leak is located, and replacing the air compressor attacks the one component the symptom exonerates, since it still refills the system every time the truck runs.

Correct answer: A swiveled link at the eye that lets the pack lengthen

A shackle is a swiveled link at the eye that lets the pack lengthen. As a leaf spring flattens under load its ends move apart, so one end must be free to swing; the shackle provides that pivoting freedom while still carrying the load. A welded mount at the frame that holds the beam steady is the opposite arrangement — the fixed hanger at the other eye. A tight clamp at the middle that grips the leaves hard describes the center-bolt and clamp area, and a steel pin at the seat that locates the axle squarely describes the center bolt itself, neither of which pivots.

Correct answer: A dull knock from the joint over bumps and slight axle offset

Worn shackle parts announce themselves as a dull knock from the joint over bumps and slight axle offset. Sloppy bushings and a loose pin let the spring end move before it loads, which knocks, and the same slack lets the axle creep out of position. A stiff pedal from the brake over stops and extra ankle force is a braking hydraulic or friction complaint. A frothy head from the fluid over time and cloudy tank levels points to air drawn into the power-steering circuit, and a shrill note from the pump over turns and heavy wheel effort points to a starved or failing steering pump — none of which a shackle can produce.

Correct answer: Technician A is precise, B is misled

Technician A is precise, B is misled. A cracked leaf drops the pack's load capacity, so that corner settles and the broken section can pop or clunk as it works against its neighbors — exactly what A describes. B is wrong to call a single cracked leaf safe to leave: the remaining leaves then carry more than they were rated for and the crack usually spreads, so the pack is replaced even when the main leaf still looks sound. Because A's account holds up, this is not a case where A is mistaken and B is wrong. Because B's does not, it is not a case where A is right and B is accurate, nor one where A is astray while B is factual.

Correct answer: A sheared center bolt

Leaves that have slid sideways within the pack point to a sheared center bolt. That bolt passes through every leaf and pins the pack to the axle seat, so when it breaks the leaves are free to shift and the axle can move with them, tipping the bed to one side. A swollen air bellows and a sticky height valve belong to an air-ride system, which has no leaf pack to shift, and a damaged fifth wheel sits above the frame at the coupling and cannot move leaves relative to one another.

Correct answer: Bags level height and soften jolts, while leaves stay plain and sturdy

The accurate comparison is that bags level height and soften jolts, while leaves stay plain and sturdy: a height-control valve keeps an air system at one ride height however the load changes and the air column gives a gentler ride, whereas a leaf pack is mechanically simple and stands up well to heavy and off-road work. Leaves cannot trim posture and cancel squat on their own, because a steel spring deflects further as load rises and nothing resets it. Bags do not kill motion and drop dampers — air suspensions still run shock absorbers, since the bags store energy rather than absorb it. And leaves are not confined to trailers and steer beams; they are used on drive and tandem axles every day.

Correct answer: Draw the nuts in crossed stages and reach the rated torque

The correct practice is to draw the nuts in crossed stages and reach the rated torque. Working across the pattern in steps seats the pack squarely and spreads clamp load evenly over every leg. Driving the nuts in single runs and settling the lead fastener pulls the pack over to one side before the rest are touched. Blasting the nuts in quick bursts with an impact gun gives no control of the final clamp load and invites overstretch. Twisting the nuts in mixed patterns and skipping the inner couple leaves part of the clamp load missing, so the pack can shift and the remaining legs fatigue.

Correct answer: The U-bolts have yielded and need full renewal, not retorque

The findings say the U-bolts have yielded and need full renewal, not retorque. A necked-down shank and threads that will not hold a setting are the signature of a fastener stretched past its elastic range; it has lost the ability to generate clamp load, so tightening it again or fitting sturdy nuts to the same legs restores nothing. The center bolt is not implicated — it locates the leaves, it does not clamp the pack to the axle — so center repairs miss the defect. And the legs have plainly not stayed intact, which is why more torque is the wrong answer rather than the cheap one.

Correct answer: Match the torque with a rated wrench and scan the clamps for cracks

The recommended method is to match the torque with a rated wrench and scan the clamps for cracks — a calibrated wrench against the published figure is the only way to know the clamp load, and the visual pass catches stretch, cracking and legs that have gone slack. Counting the studs with a speedy survey and trusting the number for proof confirms only that fasteners are present. Striking the heads with a steel hammer and judging the tone for clarity is folklore that no torque figure supports. Spinning the collars with a bare hand and assessing the grip for tightness cannot detect a nut that is tight but far below specification.

Correct answer: To anchor the axle and stop the crosswise travel

A track bar, or Panhard rod, exists to anchor the axle and stop the crosswise travel, tying the axle to the frame so it cannot walk sideways as the vehicle leans or corners. It does not soften the bounce and damp the upright motion, which is the shock absorber's role. It does not alter the caster and adjust the forward angle, an alignment setting made at the axle or shims. And it does not bear the payload and cradle the parked weight, which the air or coil springs do; a worn track bar bushing shows up as wander and poor tracking, not as a sagging chassis.

Correct answer: 3/8 in of pin gap

Movement beyond 3/8 in of pin gap between the pivot bracket pin and its bracket is an out-of-service defect under 49 CFR Part 396 Appendix A and the CVSA North American Standard Out-of-Service Criteria. 1/8 in of pin gap is inside the limit and is not itself a defect. 1/2 in of pin gap is the separate threshold that applies to horizontal movement between the upper and lower coupler halves, a different measurement on the same assembly that is easily confused with this one. 3/4 in of pin gap is past every recognized limit but is not the figure the criteria name for the pivot bracket.

Correct answer: By adjusting the lock wedges per the manual

On most fifth wheels the chucking is cured by adjusting the lock wedges per the manual: the locking mechanism carries a built-in take-up so wear between the kingpin and the closed jaws can be dialed back out. Renewing the entire deck per the catalog replaces a repairable unit and is not the first step. Cinching the mount anchors per the chart cures movement between the fifth wheel and the frame, which is a different complaint. Spreading the fresh grease per the label lowers friction on the top plate but does nothing about slack inside the lock.

Correct answer: Spread grease on the plate and jaws so the trailer swings freely

Correct practice is to spread grease on the plate and jaws so the trailer swings freely, which cuts wear on the bearing surface and keeps the coupling from binding and dragging the steering. Smearing fluid on the kingpin and collar so the surface looks clean leaves the top plate dry, and a dry plate is exactly what makes a tractor steer heavily and wear its deck. Refusing polish on the decks and ramps because the latches clamp firmly confuses the lock, which does not need grease to hold, with the bearing face, which does. Scattering powder on the rails and studs so the debris drifts aside substitutes a dry film for the grease the manufacturer specifies on the plate.

Correct answer: Drill a small stop hole at the crack tip to halt the spread

Before welding, the technician should drill a small stop hole at the crack tip to halt the spread. The hole removes the sharp crack tip where stress concentrates, so the crack cannot run further and the weld repair will hold. Aiming a large gas torch at the crack tip anneals heat-treated frame steel and weakens it, grinding a broad rail flat there shaves away section strength, and welding a thick alloy patch over the hole leaves the live crack tip untouched underneath.

Correct answer: Pouring torch heat on a rail to bend or straighten it

The prohibited practice is pouring torch heat on a rail to bend or straighten it. Heat-treated alloy frame steel loses its temper and its fatigue strength when it is overheated, so most manufacturers forbid hot straightening and cap the heat input even during a sanctioned weld. Bolting graded plate on a rail to brace or stiffen it, scrubbing paint layers on a rail to clean or strip it, and running approved rods on a rail to weld or restore it are all accepted repair practices rather than prohibited ones.

Correct answer: The track grooves and lock pockets are grimy and unoiled

The most likely cause is that the track grooves and lock pockets are grimy and unoiled. Road grime packs into the slide rails and into the plunger pockets and binds the slider even after the plungers are released, so cleaning and lubricating restores travel. The trailer kingpin and lock jaws being scoured and pitted would affect coupling rather than sliding, the mount bracket bolts and plates being torqued and tight is the normal condition, and the pickup ramps and approach plates being buckled and low would affect hook-up, not travel along the rails.

Correct answer: The rubber bushings pressed onto the rod ends

The component most likely worn is the rubber bushings pressed onto the rod ends. Torque rods locate the axle and control fore-and-aft movement, so when their end bushings break down the axle shifts under acceleration and braking, producing the clunk and an altered pinion angle. The steel bead plates welded onto the springs carry vertical load, the pleated boots slipped onto the shock rods only keep dirt off the shaft, and the collar nuts threaded onto the U-bolt legs clamp the axle seat; none of the three controls fore-and-aft axle location.

Correct answer: Fit the maker kit jaw and lock set to restore the clamp

The correct action is to fit the maker kit jaw and lock set to restore the clamp. Once wear exceeds the adjustment range the jaws can no longer close tightly on the kingpin, so further adjustment cannot restore a safe lock and the worn parts have to be renewed from the manufacturer's rebuild kit. Slipping the thin steel shims and jaw pad to take the slack, pulling the lock bolt and clamp down hard to close the gap, and raising the air bag and ride height up to load the throat all leave the worn jaws in service.

Correct answer: Rough kingpin entry, a tipped trailer stance, and lopsided axle loads

Improper fifth wheel height produces rough kingpin entry, a tipped trailer stance, and lopsided axle loads. When the fifth wheel sits too high or too low the kingpin does not enter the throat cleanly, the trailer rides nose-up or nose-down, and weight is shifted wrongly between the drive and steer axles. Feeble engine oil with a slack gallery feed is a lubrication fault, rapid nozzle washout with a burnt spray cone is a fuel system fault, and lost trailer pulses with a blank speed signal is a wiring or sensor fault; none of them is caused by coupling height.

Correct answer: Front axle misalignment

Correct answer: Front axle misalignment. When the steering itself behaves normally, a steady lateral drift points at the geometry of the front axle, because an axle out of square makes the truck track toward one side. Faulty hydraulic assist changes how heavy the wheel feels, not which way the truck tracks. Irregular shoulder wear is a consequence of poor geometry rather than its cause. A scored steering knuckle would announce itself as noise, looseness or binding long before it produced a smooth, steady pull.

Correct answer: Drag link readjustment

Correct answer: Drag link readjustment. On a recirculating ball box the drag link sets where the wheel sits relative to the gear, so shortening or lengthening it re-centers the rim without disturbing anything else. Sector gearbox renewal is an expensive repair for a symptom that is purely an adjustment. Front axle realignment corrects tracking and tire wear, not rim position. General linkage checks are worth doing, but they diagnose looseness and leave the off-center rim exactly where it was.

Correct answer: Front axle geometry

Correct answer: Front axle geometry. A steady one-way drift means the steered wheels are not pointing where the chassis is traveling, so camber, caster and toe at the front axle are checked before anything else. Left tire condition is usually an effect of poor geometry rather than its cause. Linkage ball joints create wander and vagueness, not a constant heading error. Chassis frame twist is rare and is investigated only after the routine angles have been measured and found correct.

Correct answer: Affected wheel alignment

Correct answer: Affected wheel alignment. Wear confined to one side of the truck points at the angles set for that wheel, because camber and toe errors scrub the tread on that side only. Overall inflation levels would mark both sides alike, center-worn or shoulder-worn. Suspension bellows leaks change ride height without producing a directional scrub pattern. Incomplete brake release heats the wheel and wears the lining rather than cutting a one-sided pattern into the tread.

Correct answer: Bent steer axle beam

Correct answer: Bent steer axle beam. Camber on a solid front axle is built into the forging, so the only way one wheel can read excessively positive is if the beam itself has been bent upward at that end. Worn inner hub races allow the wheel to wobble, which gives an unstable rather than a consistently positive reading. Failed air ride bags change height, and the steer axle rarely carries them. Rapid tire edge wear is a symptom of the wrong camber, not a way of creating it.

Correct answer: Bent suspension members

Correct answer: Bent suspension members. Thrust angle describes where the rear axle is aimed relative to the chassis centreline, and that aim is held by the locating members, so a bent one swings the axle off square. Slack trunnion bushings let the axle move under load but it returns to position at rest, giving a varying rather than a fixed error. Inaccurate toe settings and misaligned front wheels are both properties of the front end and have no bearing on where the rear axle points.

Correct answer: Worn tie rod sockets

Correct answer: Worn tie rod sockets. The cross tube sets toe, so slack in its end sockets lets each wheel find its own angle as the truck rolls, which both throws the measured toe out and produces the scrubbed tread and wander described. Poor tire air levels wear the center or the shoulders symmetrically and do not disturb toe. A bent pitman arm stud shifts the wheel off center without opening up toe. Low pump assist flow changes effort at the rim and has no effect on geometry.

Correct answer: Drag link length

Correct answer: Drag link length. The drag link is the adjustable connection between the steering gear output and the steered wheels, so altering its length rotates the steering wheel relative to the road wheels and brings it back on center while the truck is driving straight. Gear sector lash controls free play, not rim position. Forward axle toe governs tire wear and is set independently of where the steering wheel sits. Knuckle pin tilt is built into the axle and cannot be adjusted to center anything.

Correct answer: Steer wheel toe angles

Correct answer: Steer wheel toe angles. Toe is the angle that scrubs tread across the road as the truck moves forward, so a toe error is both the usual explanation for a feathered pattern and the cheapest angle to measure, which puts it at the head of the list. Front hub camber angle wears one shoulder rather than feathering the whole tread. Rear axle thrust error shows on the rear tires first. Pitman arm socket play makes the steering vague but will not cut a steady wear pattern.

Correct answer: Irregular tread wear

Correct answer: Irregular tread wear. A rear axle that is not square to the front one makes the truck crab, so its tires are dragged sideways as they roll and the tread is scrubbed into an uneven pattern. Steering wheel shake comes from rotating imbalance, not from tracking error. Unequal brake effort depends on foundation brake condition and air delivery, neither of which alignment touches. Reduced fuel economy does follow a crabbing chassis, but it is a secondary effect and appears long after the tires show it.

Correct answer: Negative camber angle

Excessive negative camber angle tilts the tops of the tires inward so the inner shoulder carries the load, which is exactly what produces inside-edge wear. A positive toe-in angle scrubs the tread sideways and wears the outer shoulders with a feathered edge instead. Caster is a directional-stability angle that does not tilt the tire against the road, and a reversed thrust angle shows up as dog tracking with an off-center steering wheel rather than one-sided wear.

Correct answer: Adjustable axle torque rods

Adjustable axle torque rods are what the technician adjusts, because the torque rods locate the axle fore and aft and set its angle to the frame, so lengthening or shortening them moves the axle back into alignment. Laminated axle spacer shims change axle spacing and pinion angle rather than the rod-controlled alignment. Spring bracket axle U-bolts only clamp the spring to the axle seat and have no adjustment range, and forward leaf spring hangers are fixed frame brackets.

Correct answer: Left-side wheel angle settings

Left-side wheel angle settings are the next thing to check: when a truck pulls right after an alignment, the opposite side's camber and caster are compared to spec to find the cross difference that drives the pull. Right-side brake caliper force would produce a drag pull that also shows as heat and uneven lining wear, so it is not an alignment finding. Left-side tire inflation level belongs to the pre-alignment setup, and right-side wheel bearing float causes looseness and noise rather than a steady pull.

Correct answer: Improper total toe adjustments

Improper total toe adjustments cause feathered wear, because a toe error makes the steer tires scrub sideways as they roll and shaves one face of every tread rib. Incorrect camber angle setting tilts the tire and polishes one shoulder smooth instead. Worn steering linkage bushings produce wander and erratic wear rather than the uniform feathered pattern, and mismatched radial tire casings give pull or bulges.

Correct answer: Front wheel alignment angles

Front wheel alignment angles are inspected first, because camber, caster and toe errors account for the irregular tread wear and the loss of directional stability in a single fault. Steering linkage socket wear explains the wander on its own but not the wear pattern. Rear suspension bushing wear shifts axle position under load, and steer tire inflation numbers are routine maintenance rather than a cause of both complaints together.

Correct answer: The inward or outward lean of a wheel rim

Camber is the inward or outward lean of a wheel rim away from vertical, read from in front of the truck; leaning out at the top is positive and leaning in at the top is negative. The front or rear spread of a wheel plane is toe, a comparison of the leading and trailing edges seen from above. The inner or outer slope of a wheel shaft is steering axis or kingpin inclination, an angle of the pivot rather than of the wheel. The forward or back tilt of a wheel pivot is caster, read from the side of the truck.

Correct answer: Caster angle

The fore-and-aft tilt of the steering axis seen from the side of the truck is the caster angle, measured in degrees, with rearward tilt at the top counted as positive; that trailing effect is what gives directional stability and return-to-center. The camber angle is read from in front and describes the tilt of the wheel itself. The thrust angle relates the direction the rear axle points to the vehicle centreline and has nothing to do with the kingpin. The toe-in angle compares the leading and trailing edges of a pair of tires seen from above.

Correct answer: Recenters the wheel and steadies the course

Positive caster recenters the wheel and steadies the course: tipping the top of the steering axis rearward puts the contact patch behind the pivot, so the tire trails and self-centers, which is why heavy steer axles run several degrees of it. It does not lighten the scrub and flatten the surface; straight-line scrub is governed by the toe setting. It does not override the toe-in and void the adjuster, since toe still has to be set independently. And it does not equalize the payload and angle the casing, which describes what camber does under load.

Correct answer: Toe-in, shown in inches

Leading edges closer together than trailing edges is toe-in, shown in inches on a heavy-truck alignment report; a small static toe-in is normal so the steer tires roll parallel once driving loads push them apart. Toe-out, read in tenths, is the opposite relationship, with the leading edges further apart. Camber, seen in degrees, describes how far the wheel leans from vertical rather than how the pair is spaced. Caster, held in minutes, describes the fore-and-aft tilt of the steering axis and says nothing about the spacing of the tires.

Correct answer: Total toe is the sum of two wheel angles set from the centerline

Total toe is the sum of two wheel angles set from the centerline, each side being measured against the thrust line or geometric centreline and then added together. That is why an axle can show correct total toe and still steer badly: the split between the sides may be uneven, which throws the steering wheel off center and can produce a lead. Total toe is not the mean of paired axle values taken from the frame, since averaging would halve the figure. It is not the twin of one side figure split from the midpoint either, because the sides are only equal halves when the split happens to be even. And it is not the match of one plain number read from mixed units; individual toe and total toe are genuinely different quantities, not one quantity in two units.

Correct answer: Uneven caster, with the left side steeper

With camber and toe in specification, the likely cause is uneven caster, with the left side steeper. A truck drifts toward the side carrying the lower caster figure, so a left side that is more positive than the right pushes the vehicle steadily to the right at every speed. Excess toe-in, with the front tires tight, scrubs the tread and wears it fast but does not steer the truck to one side. Zeroed thrust, with the tandem axle level, is the condition you want, not a fault. Even camber, with the two wheels positive, is symmetrical, and symmetrical angles cancel rather than pull.

Correct answer: Technician A is sound, B is genuine

Technician A is sound, B is genuine. Steering axis inclination, also called kingpin inclination, is exactly what A describes: the angle of the kingpin away from vertical as read from in front of the truck. B is right as well, because SAI is designed into the axle and knuckle and cannot be adjusted, which is precisely what makes it useful — comparing the measured figure side to side exposes a bent spindle, knuckle or axle that camber alone would not explain. Neither account is defective, so this is not a case where A is faulty and B is untrue, nor one where A is awry while B is reliable, nor one where A is assured while B is amiss.

Correct answer: The inward lean of the pivot axis

Kingpin inclination is the inward lean of the pivot axis away from vertical, read from in front of the truck, and it is the same angle called steering axis inclination on an independent front end. That inward lean brings the pivot point close to the center of the tire footprint, which cuts steering effort and helps the wheel return to center. The offset angle of the rod links describes steering linkage geometry, not a wheel angle. The uneven spread of the toe pair is a toe split. The rearward tilt of the hub post, seen from the side, is caster.

Correct answer: The included angle

Camber added to steering axis inclination gives the included angle for that wheel. Because SAI is built into the parts and cannot be adjusted, comparing included angle side to side isolates the fault: equal SAI with unequal included angle puts the difference in camber, which points at a bent spindle or knuckle. Kingpin offset describes where the steering axis meets the road relative to the tire center and is not a sum of two angles. Setback number compares the fore-and-aft position of the two front wheels. Thrust figures describe where the rear axle points relative to the centreline.

Correct answer: Technician A is proven, B is truthful

Technician A is proven, B is truthful. Scrub radius is measured at the road surface, between the point where the steering axis line reaches the ground and the centreline of the tire, which is what A states. B holds up too: the figure is set by SAI, camber and wheel offset, and it should match side to side, because an unequal scrub radius — commonly from a wheel of the wrong offset or from collision damage — produces a strong pull and unsettled steering. So this is not a case where A is right and B is imprecise, nor one where A is mistaken and B is untrue, nor one where A is misguided while only B is valid.

Correct answer: Positive tips the crown outward, negative tucks it inward

The correct statement is that positive tips the crown outward, negative tucks it inward: with camber, the reference point is the top of the wheel as seen from the front, so leaning away from the truck is positive and leaning toward it is negative. Excess positive scrubs the outer shoulder of the tread and excess negative scrubs the inner shoulder. Saying positive leans the apex inward, negative casts it outward simply reverses the convention. Saying positive kicks the base outward, negative drags it inward reads the bottom of the wheel instead of the top. And saying positive rolls the pivot outward, negative sets it inward describes movement of the steering axis, which is inclination, not camber.

Correct answer: Frame centerline and the rear wheel course

Thrust angle is the angle between the frame centerline and the rear wheel course — the geometric center of the truck compared with the direction the rear axle actually points, which is the bisector of its toe. The alignment equipment reports the difference, and anything other than zero means the rear axle is steering the truck slightly off the centreline, producing dog tracking and an off-center steering wheel. The left steer measure and the right aggregate are individual toe readings on the front axle. The chassis crossbeam and the drag link mounts are structural and steering parts with no angular relationship of this kind. The kingpin slope and the vertical line marker describe steering axis inclination.

Correct answer: Dog tracking

Rear wheels running to one side of the fronts instead of directly behind them is dog tracking — the truck appears to move slightly crabwise, and the cause is a rear axle thrust angle that is not zero. Toe changing is the alteration of toe as the suspension moves through its travel, which shows up as a twitch over bumps rather than a steady offset. Axle walking is fore-and-aft creep of an axle in its seats, which can help create the condition but is not its name. Pin knocking is the noise of a worn kingpin and has nothing to do with where the rear wheels track.

Correct answer: Technician A is accurate, B is factual

Technician A is accurate, B is factual. A sheared center pin or slack U-bolts do let the axle move in its seats on a leaf-spring rear suspension, and an axle sitting skewed is exactly what creates a thrust angle and the dog tracking that follows, so A has the cause pinned down. B has the repair pinned down as well: the job is to bring the thrust line back onto the centreline, which is done by repositioning the axle with offset spring shims, axle-locating hardware or a torque-rod adjustment. Neither man is wide of the mark, so this is not a case where A is imprecise and B is honest, nor one where A is inexact and B is mistaken, nor one where A is right and B is unreliable.

Correct answer: How far one spindle sits behind the mate

Setback is how far one spindle sits behind the mate, measured along the length of the truck rather than across it. On the steer axle it is reported as the fore-and-aft difference between the two front wheels and usually traces back to a bent axle, collision damage or worn locating hardware. How far one casing sits inside the frame is a clearance check at full lock. How far one kingpin sits off the upright is steering axis inclination. How far one bogie sits against the steer is a wheelbase dimension, not an alignment angle.

Correct answer: The bogie points sideways, so the wheel rides crooked

A thrust angle other than zero tells the technician that the bogie points sideways, so the wheel rides crooked: the rear axle is aimed off to one side, the truck crabs down the road, and the driver has to hold the steering wheel off center to go straight. That reading sends the work to the rear axle before anything on the front end is touched. It says nothing about whether the caster reads steeper, so the column feels heavier, which is a steer-axle setting. It does not report that the kingpins measure loose, so the drums shake loudly, and it carries no tire-pressure information, so the casings gauge spongy, so the shoulder scuffs fast is unrelated.

Correct answer: Ackermann steering geometry

The inside wheel turning more sharply than the outside one is produced by Ackermann steering geometry: the steering arms are angled so that lines drawn through them meet near the center of the rear axle, which makes the inner wheel take the tighter radius it needs to follow. It is a deliberate design feature, not a fault, so collapsed steering bushings cannot create it — worn parts only spoil it. Unmatched steering kingpins would give an unwanted difference rather than the designed one, and excessive steering kickback is a symptom felt at the wheel, not a source of turning-angle difference.

Correct answer: A bowed steering arm

A bowed steering arm is the most likely cause, because the difference in turning angle between the inside and outside wheels is set by the length and angle of those arms; bend one on a curb or in a collision and the inner wheel no longer sweeps its extra amount. A loose steering box adds free play at the wheel but does not change the geometric relationship between the two front wheels. A stiff steering pin raises effort without altering the swept angles, and a slack steering rod lets the toe wander while leaving the arm geometry that produces toe-out on turns intact.

Correct answer: Technician A is right, B is sound

The verdict is that Technician A is right, B is sound. Bump steer is an unwanted toe change that steers the wheels as the suspension compresses and rebounds, so A's description holds. On a lifted solid front axle the drag link and track bar are no longer parallel, the two links sweep different arcs as the axle travels, and the axle is steered by its own suspension movement, so B's cause holds too. A dropped pitman arm that restores parallel geometry is the usual fix. Any reading that calls A wrong is false, and any reading that calls B amiss is false.

Correct answer: Camber is wheel lean off vertical in a frontal view, caster is steering axis rake in a side profile, and toe is the fore-and-aft gap in tire spacing read from a high vantage

The fully correct statement is that camber is wheel lean off vertical in a frontal view, caster is steering axis rake in a side profile, and toe is the fore-and-aft gap in tire spacing read from a high vantage. These are three separate angles read from three separate vantage points, which is why each is checked on its own during a heavy-truck alignment. The clearance a dual pair retains in a freighted state, spring line wandering from a trailing axle and the sweep a drag link traces in total lock are spacing and travel measurements, not camber, caster or toe. Degrees a spindle elevates near a bearing facet, inches a rim scrubs in a tightening bend and the twist a frame takes from a heavy hauling burden are not steering angles at all. Pitching a cabin sustains in a rolling standstill, the slackness a kingpin leaves in a worn bushing and the angle a pitman arm swings from a gear describe body movement, joint wear and linkage travel instead.

Correct answer: Chassis and axle static height

The technician must first verify and correct chassis and axle static height, which is the ride height of the frame over the suspension. Every alignment angle is referenced to that height, so worn springs, an air-leveling fault or uneven loading will shift caster, camber and toe and make the readings meaningless. Wheel and column excess travel, pump and pulley drive pressure, and brakes and drum adjustment gap are unrelated prechecks that do not establish the geometric baseline alignment work depends on.

Correct answer: The drive axle thrust line

The primary reference is the drive axle thrust line. In a thrust-line (total four-wheel) alignment the rear drive axle's thrust line is established first and the steer axle toe is then set parallel to it, which centers the steering wheel and removes dog tracking. The steer axle center line is the thing being aligned rather than the reference, the frame beam rivets line can itself be out of square with the axles, and the crown gear pinion line is a driveline measurement that says nothing about the direction the rear axles push.

Correct answer: Set the bags and validate a rated ride height

The technician must first set the bags and validate a rated ride height. Alignment angles such as caster and toe change as the suspension moves, so on an air-ride truck the height-control valve and the resulting ride height have to be confirmed to specification before any reading is taken; measuring at the wrong height gives false numbers and wrong adjustments. Exhausting the ride bags and draining a backup tank collapses the suspension entirely, hoisting the axle and placing a tall stand upright unloads it, and locking the wheel and clamping a straight rod tight does nothing about height.

Correct answer: Front tire balance

Correct answer: Front tire balance. A steering wheel that vibrates only once the truck reaches highway speeds is being driven by a rotating mass, and an out-of-balance front assembly is both the commonest source and the quickest thing for the technician to verify, so it is inspected first. Loose hub bearings usually announce themselves as wander or noise across the whole speed range. A dead shimmy damper allows an oscillation to persist but does not start one. Assist fluid level affects steering effort, never vibration frequency.

Correct answer: Tire assembly balance

Correct answer: Tire assembly balance. A disturbance whose amplitude climbs steadily with road speed is driven by a rotating mass, and the mounted tire and rim are the first and easiest rotating assembly to verify. Driveline joint angle produces a shudder tied to torque and throttle rather than a smooth rise with speed. Cold inflation values change ride harshness, not the frequency of the shake. Spring pack condition alters how the chassis reacts to a disturbance but cannot create one.

Correct answer: Tire rim balance

Correct answer: Tire rim balance. A shake that appears only once road speed is high is driven by a rotating mass, and an unbalanced mounted assembly produces exactly one disturbance per revolution, which is felt at the rim. A steer damper rod can let an existing oscillation continue but cannot start one. Tie rod bushings give vagueness and wander across the whole speed range. Front toe angles scrub the tread and pull the truck sideways without shaking the rim.

Correct answer: Tapered roller bearing cones

Tapered roller bearing cones are inspected first, since a hub that runs hotter than its mates almost always points to bearing trouble from poor lubrication, wrong adjustment or spalling raceways. Brake drum lining clearances would put the heat at the drum and shoe rather than inside the hub. Steer tire inflation reading has no path to hub temperature, and outboard hub lubricant seals are examined once the bearings themselves have been judged.

Correct answer: Weak hydraulic shock absorbers

Weak hydraulic shock absorbers are the usual source of cupping, because a damper that no longer controls wheel bounce lets the tire skip along the road and scallop the tread in regular patches. Excessive steer tire inflation produces center-rib wear rather than a scalloped pattern. Misaligned drive axle housings make the truck dog-track and wear the tread diagonally, and worn tie-rod ball-stud sockets show up as wander with feathered toe wear.

Correct answer: Gradual steer tire underinflation

Gradual steer tire underinflation is the probable cause: a soft tire rolls on its shoulders, so both outer edges carry the load and wear away first. Constant steer tire overinflation does the opposite and wears the center rib. Improper wheel bearing adjustment brings looseness, heat and irregular scalloping rather than even shoulder wear, and misadjusted steering toe settings leave a feathered edge across each tread rib.

Correct answer: Steer wheel assembly balance

Steer wheel assembly balance is checked first, because a vibration that arrives at one particular road speed is almost always an imbalance in the rotating wheel and tire. Universal joint bearing wear gives a driveline vibration tied to driveshaft speed, which changes with gear selection. Steering linkage socket play causes wander and shimmy under different conditions, and drive axle thrust alignments show up as dog tracking with diagonal tread wear.

Correct answer: Underinflated inboard dual tires

Underinflated inboard dual tires are the likely cause, since a soft mate in a dual set flexes more, builds heat and scuffs against the pavement, so it wears abnormally beside its partner. Misaligned tandem drive housings wear both tires on an axle diagonally rather than singling out one. Overinflated outboard dual tires would wear their own center ribs, and faulty rear suspension fasteners bring noise and axle shift rather than one-tire wear.

Correct answer: Radial tire construction pull

Radial tire construction pull is the likely cause, because a belt or ply that sits slightly off inside a new radial steers the truck to one side even though nothing else on the vehicle changed. Incorrect axle alignment pull would have been present long before the tires were swapped. Reversed tire tread direction affects traction and noise instead of steering, and a defective power steering pump cuts assist evenly on both locks.

Correct answer: Aluminum hubcap or grease seal

Aluminum hubcap or grease seal is the first thing to check, since the cap, its gasket and the hub seal are the parts that hold lubricant inside the wheel end and are the usual source of a leak. Outer wheel bearing cone races are examined only once the leak path is known. Spindle nut or tapered washers set bearing adjustment rather than retain lubricant, and a brake shoe lining grease stain is evidence left by the leak rather than its origin.

Correct answer: Wheel hub lubricant seals

Wheel hub lubricant seals are the likely leak: oil found on the inner face of a rim has run out of the hub past a failed seal and down the wheel disc. A rear brake wheel cylinder releases brake fluid inside the drum rather than lubricant onto the rim. A disc brake caliper piston also passes brake fluid and sits outboard of the rim face, and front shock absorber rods weep onto the damper body well away from the wheel.

Correct answer: Accepted, as a 0.001 to 0.005 inch end-play band admits the 0.003 rocked hub reading

The reading is accepted, as a 0.001 to 0.005 inch end-play band admits the 0.003 rocked hub reading. TMC Recommended Practice RP 618 specifies that window for conventional adjustable wheel bearing systems, and the procedure calls for verifying end play with a dial indicator and recording it on the work order. Zero end play is not a steer axle requirement, so nothing has to achieve a 0.000 inch benchmark; no 0.002 inch threshold is dictated by a corroded cup; and shimming the cone surface to remove the residual movement is neither needed nor part of a double-nut adjustment.

Correct answer: To support the wheel load and let a hub revolve on a spindle almost drag free

A wheel bearing exists to support the wheel load and let a hub revolve on a spindle almost drag free. Heavy trucks use tapered roller bearings in inner and outer pairs that take both radial and thrust loads while the spindle stays fixed. To center the wheel disc and seat a rim square on a pilot ring machined round is the hub pilot's job, to channel the wheel braking torque and press a shoe on a drum face very hard is foundation brake work, and to capture the wheel oil bath and maintain a light film on a seal lip surface is what the hub seal does.

Correct answer: Technician A is accurate, B is reliable

The verdict is that Technician A is accurate, B is reliable. The accepted sequence is to torque the adjusting nut while rotating the hub so the rollers seat, back the nut off to release that load, then re-tighten to the final specification before locking it, so A is accurate. End play then has to be read with a dial indicator rather than judged by hand, because the acceptable window is only 0.001 to 0.005 inch, so B is reliable as well. Any verdict calling A mistaken is false, and any verdict calling B confused is false.

Correct answer: A wheel drawn straight by tapered conical seats where the lug nuts engage its stud holes

A stud-piloted wheel is a wheel drawn straight by tapered conical seats where the lug nuts engage its stud holes; tightening the nuts pulls those cone seats into the tapered holes and centers the wheel on the studs. A machined hub ring embracing the bore describes a hub-piloted wheel, two-piece flange nuts on a flat mount face are also a hub-piloted feature, and no truck wheel is retained by friction on bare stud shanks.

Correct answer: 450 to 500 ft lb

Two-piece 33 mm flange nuts on a hub-piloted assembly are tightened to 450 to 500 ft lb when applied dry, per wheel and rim manufacturer specifications and TMC guidance, using a calibrated torque wrench in a criss-cross pattern. The 250 to 300 and 150 to 200 figures are far too low and leave the clamp load short, which is how wheels come loose, while 700 to 750 over-stresses the studs and can stretch or snap them.

Correct answer: Technician A is factual, B is precise

The verdict is that Technician A is factual, B is precise. Hub-piloted wheels are indeed centered by the hub bore seating over a machined pilot ring on the hub, so A is factual. They also use right-hand threads on both sides of the truck, whereas stud-piloted systems need left-hand threads on the driver side and right-hand threads on the passenger side, so B is precise as well. Any verdict calling A invalid is false, and any verdict calling B unsound is false.

Correct answer: A sloppy or worn wheel bearing

The symptoms point to a sloppy or worn wheel bearing. A damaged bearing growls and rumbles, changes note as cornering shifts the load from one side of the rollers to the other, and lets the hub move about, which the driver feels as a wobble through the steering. A bent or cracked wheel casing gives a steady vibration rather than a load-sensitive growl, a rigid or bulging wheel tread from overinflation produces neither noise nor looseness, and a heavy or shifting wheel mass causes a speed-related shake with no play in the hub.

Correct answer: The sideways wobble of a wheel read square to the rotation axis

Lateral runout is the sideways wobble of a wheel read square to the rotation axis, captured by indicating against the rim flange face while the wheel is turned. The endwise float of a wheel read parallel to the spindle shaft is bearing end play, not runout; the girth imbalance read relative to the tread width describes a dual diameter mismatch; and the up-down bounce read vertical to the roadway path is radial runout, which is the other measurement entirely.

Correct answer: Rapid tread wear as the smaller tire scuffs along to match its bigger mate

The likely result is rapid tread wear as the smaller tire scuffs along to match its bigger mate: the smaller dual must slip on the pavement to cover the same ground, which destroys tread life and pushes extra load onto the taller tire. TMC guidance keeps duals within 1/4 inch of diameter, so a 1/2 inch difference on 11R22.5 tires is double the limit. A mismatch does not reduce fuel burn, it does not ease the load the axle carries, and the trivial change in loaded radius is not a wear-free ride height gain.

Correct answer: The soft tire turns a smaller roll radius, so the duals fight and wear fast

The mismatch matters because the soft tire turns a smaller roll radius, so the duals fight and wear fast. The tire at 95 psi deflects more and covers less ground per revolution than its mate at 110 psi, so the two scrub against each other, building heat and rapid irregular wear. An uneven tire does not merely shift a front steer angle and leave the duals idle to wear slow, a paired tire sharing a solid axle beam does not level them so they wear alike, and a rigid tire running a harsher hot casing does not simply age the duals and wear them thinner regardless of matching.

Correct answer: Lets the hub lube level show inside a sight glass and stays cooler in constant highway work

The advantage is that an oil bath lets the hub lube level show inside a sight glass and stays cooler in constant highway work, because the oil circulates and carries heat away from the rollers during sustained high-speed running. It does not kill the hub roller adjust step and keep a fixed preload through rough remote sandy field work, because the bearings still have to be adjusted; it does not shut the hub cavity totally tight and block a stray leak in deep muddy swampy quarry work, because a failed seal will drip oil onto the brake; and it does not remove the hub seal ring itself or slash a spare parts cost in busy suburban fleet work, because the seal is still fitted.

Correct answer: A camber error that tilts the tire so a lone edge carries the load

Single-shoulder wear comes from a camber error that tilts the tire so a lone edge carries the load. With the wheel leaned away from vertical, one side of the tread is pressed harder into the road and wears away first while the rest of the tread stays healthy. A scored hub that shakes the tire produces a wobble and a growl rather than one worn edge, a soft sidewall that squats the tire wears both shoulders together, and a dead damper that bounces the tire cups the tread right around the circumference.

Correct answer: A buckled axle beam or a skewed shackle that leaves a scrub angle

Diagonal scuff bands are associated with a buckled axle beam or a skewed shackle that leaves a scrub angle. The axle is no longer square to the direction of travel, so the tire is dragged slightly sideways as it rolls and the wear runs at an angle across the tread. A right axle toe figure or level camber leaves no scrub to create a diagonal band, a high air charge or a rigid sidewall wears the center rib instead, and a precise wheel balance or a light rim has no bearing on an angled wear pattern.

Correct answer: Spaced opposite a mate and reached through the outer hand holes

The two stems should be spaced opposite a mate and reached through the outer hand holes. Setting the valve stems 180 degrees apart and lining them up with the access holes in the outer wheel lets the driver check and adjust both the inner and the outer tire without pulling a wheel off. Angled inward beside a drum buries the inner stem where nothing can reach it, grouped alongside a pair puts one stem behind the other, and sealed behind a shroud is not how a standard dual assembly is built.

Correct answer: A vertical bounce or hop that grows with road speed

Excessive radial runout most directly causes a vertical bounce or hop that grows with road speed. Radial runout is the out-of-round high and low variation of the wheel, so the tire effectively rises and falls once per revolution and the tramp gets worse the faster the truck runs. A sideways pull or drift that shows with brake wear points to a brake or alignment fault, a sudden dish or scrape that spreads with tread age is a wear pattern rather than a runout effect, and a gradual leak or bleed that builds with idle hours is an air-loss problem that runout does not cause.

Correct answer: Discard the bent ring and install a fresh matched part

The correct action is to discard the bent ring and install a fresh matched part. A bent, corroded, cracked or sprung lock or side ring can separate explosively while the tire is being inflated, so OSHA and tire-industry guidance require that a damaged ring be scrapped and replaced with the correct matching component. To polish the bent ring and reinstall a wire cleaned part leaves the distortion in place, to press the bent ring and refit a straightened flat part work-hardens a safety-critical component, and to weld the bent ring and grind a smoothly feathered part destroys the temper the ring depends on.

Correct answer: A rated safety cage or restraint frame

The assembly must be inflated in a rated safety cage or restraint frame. Multi-piece rim components can separate violently during inflation, so the wheel goes into a cage or restraining device and is inflated with a clip-on chuck and a remote in-line gauge while the technician stands clear of the trajectory. A bare uncovered shop floor or walkway gives no protection at all, a loaded tandem axle spindle or flange keeps the technician right beside the assembly, and a sturdy concrete depot wall or pillar will not contain components thrown off a separating rim.

Correct answer: A violent brake bite that locked a wheel and dragged it

The flat spot is most likely caused by a violent brake bite that locked a wheel and dragged it. Once the wheel stops turning and the tire slides, the tread abrades in one place, leaving a single worn patch across the full width while the rest of the tire stays normal. A soft underinflated run that heated a wall and tore it damages the sidewall and both shoulders, a steep camber angle that loaded a shoulder and wore it wears one edge right around the circumference, and a buckled rim wobble that rattled a drum and scuffed it produces vibration rather than one localized flat.

Correct answer: Roll diameter and girth

The technician must verify closely matched roll diameter and girth, which is the overall rolling circumference of each tire. If the two duals differ, the larger tire carries more load and scuffs while the smaller one drags, causing rapid irregular wear and driveline strain, so matching the rolling diameter keeps load and rotational speed shared evenly between them. Tread pattern and label, assembly batch and code, and valve length and offset make no difference to how the two tires share that load.

Correct answer: Lateral shimmy caused by offset load mass along a tread

Dynamic balancing also corrects lateral shimmy caused by offset load mass along a tread. Static balance deals only with single-plane, up-and-down heavy spots, while two-plane dynamic balancing distributes weight on both rim flanges to cancel the side-to-side wobble that develops when the heavy spot sits off the centreline of the tread width. Rhythmic bounce caused by a distorted rim along a wheel is runout rather than imbalance, brutal ride caused by a faulty pressure along a carcass is an inflation fault, and excessive movement caused by a sloppy taper along a hub is bearing adjustment; no amount of balancing corrects any of the three.