- Toe
- The difference between the front and rear of a pair of tires viewed from above (toe-in or toe-out). Incorrect toe is the #1 cause of rapid, feathered front-tire wear.
- Caster
- Forward/rearward tilt of the steering axis viewed from the side. Positive caster aids straight-line stability and steering return.
- Camber
- Inward/outward tilt of the wheel viewed from the front. Excess camber wears one tire edge; unequal camber causes a pull.
- Thrust angle
- The direction the rear (or tandem) axle actually points vs. the frame centerline. A non-zero thrust angle causes dog-tracking and tire wear.
- 5th wheel
- The plate-and-jaw coupling on the tractor that locks onto the trailer kingpin, carrying the trailer load and allowing it to pivot.
- Air spring (air bag)
- A rubber bellows filled with air that replaces a steel spring on an air-ride suspension. A leaking bag lowers that corner and leans the truck.
- Cupping (scalloped wear)
- A series of dips around the tread caused by the tire bouncing — usually worn shocks, loose bearings, imbalance, or a bent rim.
- Feathered tire wear
- A saw-tooth tread edge you can feel by hand, caused by incorrect toe scrubbing the tire sideways as it rolls.
- Walking-beam suspension
- A tandem-axle design where a rigid equalizing beam pivots on a center saddle to share the load between two axles; common on heavy vocational trucks.
- Kingpin (steering)
- The pin on a solid front axle about which the steering knuckle and wheel pivot. Worn kingpins cause free play, wander, and shimmy.
- Recirculating-ball steering gear
- The common heavy-truck steering gear in which balls circulate between the worm shaft and a ball nut to reduce friction and multiply effort.
- Integral power steering
- A design that combines the steering gear and the hydraulic assist in one unit — the standard arrangement on most medium/heavy trucks.
- Linkage-type power steering
- Uses a separate hydraulic power cylinder mounted on the steering linkage to assist a conventional gear.
- Power-steering pump
- Engine-driven pump that supplies pressurized fluid for steering assist. A weak pump, low fluid, or air causes hard steering and noise.
- Steering free play (lash)
- The amount the steering wheel turns before the front wheels move. Excess comes from worn linkage, a worn gear, or loose bearings — causes wander.
- Drag link
- The steering link connecting the pitman arm to the steering arm on the axle, transferring the gear's motion to the wheels.
- Tie rod
- The adjustable link connecting the two steered wheels so they turn together; the tie-rod sleeve is where toe is adjusted.
- Pitman arm
- The arm splined to the steering-gear sector shaft that converts the gear's rotation into back-and-forth motion of the drag link.
- Steering axis inclination (SAI)
- Inward tilt of the kingpin/steering axis viewed from the front. Helps self-centering; not adjustable — a change means a bent part.
- Turning radius (toe-out on turns)
- Ackermann geometry that makes the inner wheel turn sharper than the outer in a corner. An error means a bent steering arm.
- Dog-tracking
- When the rear axle doesn't follow directly behind the front because of a misaligned (non-square) axle, so the truck travels crab-wise.
- Height-control valve
- Senses ride height at the axle and adds or exhausts air from the air springs to hold the frame level as load changes.
- Ride height
- Specified distance from a frame/axle reference to the ground. Must be set correctly before alignment, or the angles read wrong.
- Shock absorber
- A hydraulic damper that controls spring or air-bag oscillation. Worn shocks let the truck keep bouncing, causing cupping and poor control.
- Leaf spring
- A stack of curved steel leaves that supports the axle and carries the load. Sag or broken leaves change ride height and can shift the axle.
- Spring center bolt
- The bolt locating the leaf-spring stack on the axle. If it breaks, the axle can shift — causing a thrust-angle error and pull.
- 5th-wheel locking jaws
- The jaws that grip the trailer kingpin. Worn jaws or excessive fore-and-aft play create an unsafe coupling — adjust or replace.
- Frame (rail)
- The truck's structural backbone. Twisting, cracks, or loose fasteners (often from overloading) misalign the axles and suspension.
- Wheel bearing (truck)
- The tapered roller bearing supporting the wheel on the spindle. Packed and adjusted to a small end play; over-tight bearings run hot and fail.
- Radial runout
- Out-of-roundness of a tire/wheel assembly that causes a speed-related vibration; corrected by truing, indexing, or replacement.
- Wheel balance
- Distributing weight evenly around a tire/wheel assembly so it doesn't vibrate at speed; imbalance causes a shimmy that worsens with speed.
- Dual wheels
- The paired rear tires on each side of a heavy axle. They must be matched in pressure and diameter, or the larger tire overloads and wears unevenly.
- Bump steer
- An unwanted change in toe (wheels steer themselves) when the suspension moves over a bump — from worn parts or wrong ride height.
- Memory steer
- The truck wanting to keep turning the way it was last steered, usually from a binding ball joint, kingpin, or steering shaft.
- Hard steering — common causes
- Low fluid, weak pump, air in the system, worn gear, binding kingpins or linkage, low tire pressure, or a dry 5th-wheel plate.
- Whining power-steering pump after service
- Usually air trapped in the system — bleed/burp it and check fluid level. Often shows as foamy, aerated fluid in the reservoir.
- Steering heavier in one direction only
- Points to a fault in the steering-gear control valve, not the pump.
- Poor steering return to center
- Insufficient positive caster, binding kingpins or column, a tight/dry gear, or low tire pressure.
- Dry-park (turning) test
- A diagnostic that turns the steering wheel slightly while watching the linkage to feel which joint has free play or binds.
- Steering shaft U-joints
- Universal joints in the steering column/shaft. Worn or binding joints cause free play, notchy steering, or poor return.
- Steering gear sector lash adjustment
- The on-center adjustment of the steering gear. Adjust only after linkage and mesh are good — over-adjusting binds the gear on center.
- Power-steering fluid
- The hydraulic fluid for the assist system. Use the specified type; low or aerated fluid causes noise, hard steering, and pump wear.
- Steering cylinder (assist)
- The hydraulic cylinder that applies power assist to the steering linkage on a linkage-type system.
- Steering damper
- A shock-absorber-like damper on the steering linkage that controls shimmy and road shock. A worn damper allows wander or shimmy.
- Ball joint (steering/suspension)
- A pivoting joint allowing the suspension and steering to move. Worn ball joints cause looseness, noise, and unstable alignment.
- Tie-rod end
- The articulating end of a tie rod. A worn tie-rod end causes excessive toe change, free play, and rapid tire wear.
- Drag-link socket
- The ball-and-socket end of the drag link. Wear here adds free play and wander to the steering.
- Pitman arm to sector shaft fit
- The pitman arm must be properly indexed/torqued to the sector shaft; looseness causes steering play and wander.
- Hydraulic power-steering relief valve
- Limits maximum system pressure to protect components; a stuck or faulty relief valve can cause hard steering or noise at full lock.
- Power-steering flow-control valve
- Regulates fluid flow from the pump so assist stays consistent across engine speeds.
- Wheel cut (lock-to-lock)
- The full range of steering movement. Stops and steering-stop bolts limit cut to prevent tire-to-frame contact.
- Steering wander
- The truck drifts and requires constant correction. Caused by worn linkage, loose bearings, low caster, or a thrust-angle error.
- Steering shimmy
- A rapid side-to-side oscillation of the front wheels, from imbalance, worn parts, or a bad steering damper.
- Power-steering belt
- Drives the pump from the engine. A loose or glazed belt causes squeal and inconsistent assist (where belt-driven).
- Steering knuckle
- The casting that holds the wheel spindle and pivots on the kingpin (or ball joints) so the wheel can steer.
- Kingpin bushing wear
- Worn kingpin bushings allow the knuckle to move, causing free play, shimmy, and unstable camber/caster.
- Steering gear mounting
- The gear must be securely bolted to the frame. Loose mounting or cracked frame at the gear causes play and erratic steering.
- Hydraulic hose (steering)
- Carries high-pressure fluid from pump to gear. A leaking or restricted hose causes assist loss, noise, and fluid loss.
- Steering effort test
- Measuring the torque needed to turn the steering wheel to confirm correct assist; high effort indicates a hydraulic or binding fault.
- Bleeding the power-steering system
- Cycling the steering lock-to-lock (often with wheels raised) and topping up fluid to remove trapped air after a repair.
- Worn steering gear (sector/worm)
- Internal wear adds lash and makes the gear loose on-center; causes free play and wander that adjustment can't fully fix.
- Steering column
- Connects the steering wheel to the gear through the shaft and U-joints. Binding here hurts return and feel.
- Steering arm
- The arm on the knuckle that the drag link or tie rod attaches to; a bent steering arm changes turning radius and toe.
- Cross tube (tie-rod assembly)
- The truck's tie-rod cross tube connecting the two knuckles; bent or worn ends throw off toe and cause wander.
- Low-fluid steering symptom
- Low power-steering fluid causes hard steering, pump whine, and aerated fluid; check level and inspect for leaks first.
- Air-over-hydraulic steering assist
- A heavy-truck assist arrangement using air pressure to boost hydraulic steering; diagnosed by checking both air supply and hydraulics.
- Steering gear input shaft seal
- Seals the gear's input shaft; a leak here loses fluid and can let air in, causing assist problems.
- Steering stops / stop bolts
- Limit wheel cut to prevent tire or linkage interference; set per spec after steering or alignment work.
- Pull during braking (steering)
- A brake pulling to one side feels like a steering pull but is a brake fault (dragging caliper/shoe), not alignment.
- Road test (steering)
- Driving to confirm the complaint and note speed, braking, and road-crown effects before diagnosing steering or alignment.
- Multi-leaf vs. mono-leaf spring
- Multi-leaf springs stack several leaves for load and damping; mono-leaf (tapered) springs use one variable-thickness leaf, often lighter.
- Spring shackle
- The swinging link at one end of a leaf spring that allows the spring to change length as it flexes.
- Spring hanger / bracket
- The frame bracket that anchors a leaf spring's fixed end; cracks or wear here cause axle shift and noise.
- U-bolts (axle)
- The bolts clamping the spring to the axle. Loose U-bolts let the axle shift and cause alignment and wear problems.
- Equalizer (tandem spring)
- The pivoting beam between two springs on a tandem that equalizes load between the axles over uneven ground.
- Torque rod (radius rod)
- A rod that locates the axle fore-and-aft and controls pinion angle on heavy suspensions. Worn bushings cause axle movement and vibration.
- Air bag leak symptom
- A leaking air spring lowers that corner, leans the truck, and may cause low-air warnings; soap-test to find the leak.
- Height-control valve misadjustment
- Sets the wrong ride height (too high or low) on a corner/axle, throwing off alignment and ride; re-adjust to the spec dimension.
- Air dryer (suspension air)
- Removes moisture from the truck's air supply feeding the suspension and brakes; a failed dryer lets water foul valves and bags.
- Leveling valve linkage
- The arm connecting the axle to the height-control valve. A bent or disconnected linkage gives wrong ride height.
- Shock absorber test
- Bounce the corner or inspect for leaks; a corner that keeps oscillating or a wet shock body means a worn shock.
- Brake dip / nose dive
- Excessive dip when braking points to worn shock absorbers (they control the load transfer), not the springs.
- Walking-beam center bushing
- The pivot bushing in the beam's center saddle. Wear causes axle misalignment, tire wear, and clunk noise.
- Walking-beam end bushings
- Bushings at the beam ends connecting to the axles; wear allows axle movement and uneven tandem loading.
- Frame cross-member
- A structural brace tying the two frame rails together; cracks or loose rivets reduce frame rigidity and cause flex.
- Frame crack inspection
- Inspect frame rails and brackets for cracks, especially at holes and welds; stop-drill and repair per the manufacturer.
- Frame fastener types
- Heavy-truck frames use Grade-8 bolts or huck/rivet fasteners; replace with the correct grade — never downgrade frame hardware.
- 5th-wheel lubrication
- The 5th-wheel plate must be greased; a dry plate causes hard steering, chatter, and uneven plate wear.
- 5th-wheel fore-and-aft play
- Excessive kingpin-to-jaw play means worn jaws or pivot bushings; an unsafe coupling — adjust or replace the lock.
- 5th-wheel slider
- A movable 5th wheel that adjusts the kingpin position to distribute axle load; the locking plungers must fully engage.
- 5th-wheel mounting
- The 5th wheel must be securely mounted to the frame; loose or cracked mounts are a serious safety defect.
- Pintle hook
- A coupling that hooks a trailer's drawbar eye for towing; inspect for wear, cracks, and proper latch engagement.
- Sway bar (stabilizer bar)
- A bar linking the two sides of an axle to resist body roll in turns; worn bushings or links cause clunk and lean.
- Spring sag diagnosis
- Measure ride height side-to-side; a sagged or broken spring lowers that corner, changing alignment and causing wear.
- Overloading effects
- Exceeding rated load sags springs, stresses the frame, overheats tires, and causes premature suspension and tire failure.
- Air suspension dump valve
- Exhausts air from the bags to lower the truck (e.g., for coupling/loading); must re-inflate to ride height before driving.
- Trailing arm (air suspension)
- The beam that locates the axle and pivots at the front bushing on many air-ride suspensions; worn bushings cause axle shift.
- Ride-height check importance
- Wrong ride height changes caster and pinion angle and skews alignment readings — always verify it before measuring angles.
- Axle seat / spring seat
- The pad where the spring sits on the axle; a shifted or worn seat changes pinion angle and axle position.
- Suspension bushing inspection
- Pry-check spring, beam, torque-rod, and sway-bar bushings for play; worn bushings cause noise, wander, and tire wear.
- Toe-in vs. toe-out
- Toe-in: fronts of the tires closer together; toe-out: fronts farther apart. Solid-axle trucks usually run a small toe-in.
- Positive vs. negative caster
- Positive caster tilts the steering axis rearward at the top (stable, self-centering). Negative caster reduces return and stability.
- Caster pull
- A truck pulls toward the side with less (more negative) caster. Unequal caster is a common cause of a steady pull.
- Camber pull
- A truck pulls toward the side with more positive camber. Excess camber also wears one tire edge.
- Included angle
- The sum of camber and SAI on a wheel; comparing side-to-side helps detect a bent spindle or knuckle.
- Scrub radius
- The distance between the tire centerline and the steering-axis contact point. Set by SAI and camber; affects steering feel and wear.
- Setback (axle)
- When one wheel of an axle is farther back than the other (axle not square). Causes a pull and crooked steering wheel.
- Thrust-angle alignment
- Squares the rear/tandem axle to the frame first, then sets front toe to the thrust line so the steering wheel is centered.
- Tandem axle alignment
- Both drive axles must be parallel and square to the frame; a shifted axle causes dog-tracking, pull, and tire wear.
- Off-center steering wheel
- A crooked steering wheel when driving straight usually means a thrust-angle error or toe set unevenly side-to-side.
- Alignment prerequisites
- Before aligning: correct tire pressure and matched tires, good linkage and bearings, correct ride height, and level equipment.
- Toe adjustment
- Set at the tie-rod sleeve/cross tube; center the steering wheel and set toe evenly on both sides, then road-test.
- Camber adjustment (truck)
- Camber on a solid axle is usually not adjustable; excess camber means a bent axle beam or spindle that must be corrected.
- Caster adjustment (truck)
- Where adjustable, caster is changed with shims or wedges between the spring and axle; otherwise a bent part is the cause.
- Diagnostic value of SAI
- SAI isn't adjustable, so an out-of-spec SAI (or unequal side-to-side) indicates a bent spindle, knuckle, or axle.
- Turning-radius error
- If the inner wheel doesn't turn sharper than the outer correctly, a steering arm is bent — replace it, don't adjust.
- Pull diagnosis: tire swap
- If a pull reverses when you swap front tires side-to-side, a tire (radial pull) is the cause, not alignment.
- Road crown vs. alignment pull
- Road crown causes a slight steady drift right; a true alignment pull is stronger and consistent regardless of the road.
- Feathered wear = toe
- A saw-tooth edge you feel by running a hand across the tread is the signature of incorrect toe.
- One-edge wear = camber
- Wear on the inner or outer shoulder of a tire points to excessive camber (or a bent axle).
- Toe set on solid axle
- On a solid front axle, toe is typically the only routinely adjusted alignment angle.
- Steering-wheel centering
- Center the steering wheel before final toe so the wheel sits straight when the truck tracks straight.
- Alignment & worn parts
- Never align over worn linkage or bearings — toe won't hold. Replace worn ends and set bearings first.
- Thrust line
- The line bisecting rear-axle toe; the front wheels are aligned to it so the truck tracks straight with a centered wheel.
- Camber wear (positive)
- Too much positive camber wears the outer tire edge; too much negative wears the inner edge.
- Caster and tire wear
- Caster mainly affects stability and return, not tire wear directly; a big caster error shows as poor return or pull.
- Alignment equipment leveling
- Alignment must be done on a level rack with the equipment calibrated; an un-level surface skews every reading.
- Front axle bend check
- Compare side-to-side camber, SAI, and included angle; mismatches reveal a bent axle beam, spindle, or knuckle.
- Pull toward lower-pressure tire
- A low front tire increases rolling resistance on that side and pulls the truck toward it — check pressure first.
- Dog-track cause
- A rear/tandem axle not square to the frame (shifted spring, broken center bolt, worn bushing) makes the truck crab.
- Tire inflation vs. load
- Inflation must match the actual axle load from the load/inflation table — not just the sidewall maximum.
- Under-inflation wear
- Too little air lets the shoulders carry the load — both edges wear and the tire overheats.
- Over-inflation wear
- Too much air makes the crown carry the load — the center of the tread wears.
- Dual tire matching
- Paired duals must match in pressure and diameter; a larger/harder tire overloads while the other scuffs, wearing the inner tires.
- Inner-tire wear (duals)
- Mismatched or under-inflated inner duals carry the load unevenly and wear early — match pressure and diameter.
- Tire cupping cause
- A bounce problem: worn shocks, loose/worn wheel bearings, imbalance, or a bent rim letting the tire hop.
- High-speed vibration
- A vibration that increases with road speed usually means imbalance, radial runout, or a bent rim — check the tire/wheel first.
- Wheel bearing adjustment
- Seat the bearing by torquing while rotating, back off, then re-torque to the light final spec to set a small end play.
- Wheel bearing end play
- The slight free movement of an adjusted tapered bearing (commonly about 0.001–0.005 in.); too tight runs hot, too loose wobbles.
- Hot hub diagnosis
- A hub running hotter than its mates means over-tight or dry bearings, or a dragging brake — investigate before it seizes.
- Preset (unitized) hub
- A sealed hub assembly torqued to a fixed spec instead of manually adjusted; replaced as a unit when worn.
- Hub oil seal
- Seals lubricant in the hub. A leaking seal lets oil onto the brake and bearing — replace the seal and clean the brake.
- Oil-bath vs. grease hub
- Some truck hubs run in an oil bath with a sight glass; others are grease-packed. Service to the correct lube and level.
- Wheel/rim inspection
- Inspect rims for cracks, bent flanges, and elongated bolt holes; a damaged rim causes runout, vibration, and air loss.
- Lug/wheel nut torque
- Torque wheel fasteners to spec in the correct cross pattern; under- or over-torque causes loose wheels or broken studs.
- Stud-piloted vs. hub-piloted wheels
- Hub-piloted wheels center on the hub and use flanged nuts; stud-piloted center on the studs and use inner/outer caps. Don't mix.
- Tire rotation (truck)
- Moving tires to even out wear; follow the truck's pattern and re-torque wheels after the specified mileage.
- Radial vs. bias tire
- Radial tires have plies running across the tread for cooler running and better wear; don't mix radial and bias on an axle.
- Tire balance methods
- Static balance corrects up-and-down hop; dynamic balance corrects side-to-side wobble. Heavy trucks usually need both.
- Lateral runout
- Side-to-side wobble of a tire/wheel assembly; excessive lateral runout causes a shimmy and must be corrected or replaced.
- Tire tread-depth limits
- Federal limits require deeper tread on steer tires than on other axles; measure with a gauge and replace worn tires.
- Steer-tire wear focus
- Steer tires show alignment problems first (feathered, one-edge, cupped) because they steer and carry front load.
- Bearing pre-load vs. end play
- Most truck wheel bearings are set to a slight end play, not pre-load; follow the spec — pre-loading runs them hot.
- Bearing cup and cone
- A tapered bearing has a cup (outer race) pressed in the hub and a cone (rollers); replace both as a matched set.
- Spindle nut and lock
- Retains and sets bearing adjustment; use the correct washer/lock and torque sequence so the setting can't change.
- Brake drag effect on tires
- A dragging brake heats the hub and can wear or overheat the tire; it also mimics a steering pull.
- Wheel weight loss
- A thrown balance weight causes a sudden vibration at the speed it was balanced for; re-balance the assembly.
- Out-of-round tire
- A tire with radial runout thumps and vibrates at speed even when balanced; correct runout or replace.
- Mismatched tire diameters
- Different rolling diameters on an axle (especially duals) scuff and wear tires and stress the drivetrain.
- Tire load/inflation table
- The chart that gives the correct cold inflation for a given axle load; the basis for setting truck tire pressure.
- Verify the concern (T5)
- Confirm and reproduce the complaint — pull, wander, hard steering, shimmy, bounce, or noise — before testing.
- Pry-bar inspection
- Using a pry bar to load joints and bushings while watching for movement to locate worn steering/suspension parts.
- Power-steering fluid foaming
- Aerated, foamy fluid means air is being drawn in — low fluid or a suction-side leak; bleed and repair the leak.
- Steering gear over-center adjustment
- Sets the gear's tightest point on-center; over-tightening causes binding and poor return, too loose causes free play.
- Steering linkage lubrication
- Grease zerk fittings on tie-rod and drag-link ends and kingpins per schedule; dry joints wear fast and bind.
- Steering effort one-way fault
- Easier in one direction, harder in the other usually means a steering-gear control-valve or torsion-bar fault.
- Steering wheel free-play spec
- Excess play at the wheel beyond the manufacturer's spec indicates worn linkage, a worn gear, or loose bearings.
- Air-bag ride-height re-inflate
- After a dump or service, the suspension must re-inflate to spec ride height before driving or aligning.
- Spring eye bushing
- The bushing at a leaf spring's eye; wear allows axle movement and clunk and affects alignment.
- Auxiliary (helper) spring
- An extra spring that engages under heavy load to add capacity; inspect for contact and wear at full load.
- Air leak isolation
- Soap-test bags, lines, and fittings to find a suspension air leak; a slow leak shows as a lean after parking.
- Shock mount / bushing
- The eyes and bushings mounting a shock; worn mounts let the shock clunk and reduce damping.
- Frame alignment (diamond/twist)
- Measuring frame rails diagonally for 'diamond' (out-of-square) and checking for twist after a collision or overload.
- 5th-wheel kingpin lock test
- Confirm the jaws fully close and lock around the trailer kingpin; a partial lock is a critical safety defect.
- 5th-wheel tilt/pivot
- The 5th wheel pivots fore-and-aft (and sometimes side-to-side) to follow the road; worn pivot bushings add play.
- Suspension noise diagnosis
- Clunks over bumps point to worn bushings, U-bolts, shackles, or shocks; isolate by location during a road test.
- Air-ride lean diagnosis
- A lean on air ride means a leaking bag or a stuck/misadjusted height-control valve — check ride height each corner.
- Broken spring leaf symptom
- A broken leaf lowers ride height, may shift the axle, and can cause a clunk and a pull on that side.
- Torque-rod bushing wear
- Worn torque (radius) rod bushings let the axle move fore-and-aft, causing vibration, pinion-angle change, and wear.
- Sway-bar link wear
- Worn stabilizer-bar links or bushings cause a rattle and increased body roll in turns.
- Pinion angle (suspension)
- The driveline angle set by axle position; a shifted axle or sagged spring changes it and causes driveline vibration.
- Frame rivet vs. bolt repair
- Replace loose frame rivets with the correct grade fasteners per the maker; never use ordinary bolts on the frame.
- Overload sag check
- Compare loaded and unloaded ride height; a corner that won't rise to spec indicates a weak spring or air-system fault.
- Air spring inspection
- Check bags for cracks, chafing, and proper inflation; a chafed bag against a frame member will fail early.
- 5th-wheel grease plate wear
- A dry plate scores and wears; it causes hard steering and chatter on turns — keep it greased and inspect the surface.
- Suspension ride-height spec
- Each suspension has a published ride-height dimension; set it before alignment and after any spring or air-bag service.
- Tandem axle parallelism
- The two drive axles must be parallel to each other and square to the frame; check both during a thrust alignment.
- Camber across an axle
- Compare left and right camber; a side that's far off (with matching SAI off) usually means a bent axle or spindle.
- Toe change over a bump
- If toe changes as the suspension moves (bump steer), suspect worn parts or incorrect ride height altering geometry.
- Alignment after part replacement
- Re-check alignment after replacing tie-rods, drag links, kingpins, springs, or shocks — geometry may have changed.
- Lead/pull troubleshooting order
- Check pressure, then tires (swap test), then brakes, then alignment angles — cheapest and most common causes first.
- Steering-wheel return after alignment
- Verify the wheel returns to center and sits straight after setting toe; if not, re-center or recheck caster and thrust angle.
- Spindle/knuckle bend check
- A bent spindle shows as abnormal camber and included angle on one wheel; replace the bent part rather than 'adjusting.'
- Cross-camber & cross-caster
- The side-to-side difference in camber or caster; too much difference causes a pull and must be brought within spec.
- Truck alignment vs. car alignment
- Heavy trucks emphasize axle squareness, ride height, and toe on solid axles; many car-style camber/caster adjustments aren't present.
- Wheel seal & bearing service
- When replacing a wheel seal, inspect and repack or replace the bearings and set adjustment — don't reuse a damaged seal.
- Tire spec matching on steer axle
- Steer tires should be matched and in good condition; a mismatched or worn steer tire causes pull and poor handling.
- Wheel bearing noise
- A growl or roar that changes with load or cornering points to a worn or improperly adjusted wheel bearing.
- Hub temperature check
- Feel or scan hub temperatures after a run; one hot hub warns of bearing or brake trouble before failure.
- Re-torque after wheel service
- Re-torque wheel fasteners after the first miles of driving following any wheel-off service to catch seating and loosening.