Your FREE ASE A4 Flashcards 2026 – 200+ Cards

The ASE Suspension & Steering certification test in the Automobile (A-series) program; covers steering, suspension, wheel alignment, and tire service.

A steering gear where a pinion on the steering shaft moves a toothed rack side to side; the rack ends connect through tie rods to the knuckles. Standard on most cars.

A steering gearbox where a worm gear turns a sector shaft through ball bearings, moving a pitman arm and linkage. Common on trucks and older rear-drive cars.

The small gear on the steering shaft that meshes with the rack to convert the steering wheel's rotation into side-to-side rack motion.

The toothed bar in a rack-and-pinion gear that moves left and right; its ends connect to the inner tie rods.

An arm splined to a recirculating-ball gearbox's sector shaft that turns the gear's motion into side-to-side movement of the steering linkage.

A pivoting support opposite the pitman arm in a parallelogram linkage; keeps the center link level. When worn, it causes steering play and wander.

The bar in a parallelogram linkage connecting the pitman arm and idler arm, to which the inner tie rods attach.

A link connecting the steering gear or center link to the steering knuckle; transmits steering motion to the wheel.

The ball-and-socket joint that connects the tie rod to the steering knuckle; wear causes play and erratic toe.

The joint connecting the tie rod to the steering rack or center link; on a rack it is protected by the bellows boot.

The threaded sleeve between the inner and outer tie-rod ends that is turned to set front toe.

The part that holds the wheel hub/bearing and pivots on the ball joints (or strut) so the wheel can steer.

A belt-driven pump that supplies pressurized fluid to a hydraulic steering gear to reduce steering effort. A failing pump causes hard steering or a whine.

Hydraulic fluid that transmits pressure and lubricates the steering gear. Low fluid or air causes hard steering, whining, or groaning.

Power assist from an electric motor instead of a hydraulic pump; more efficient and enables features like lane keeping.

Power assist using a belt-driven pump, pressurized fluid, and a control valve in the steering gear.

The assembly that multiplies the driver's effort and converts steering-wheel rotation into the motion that steers the wheels.

A shock absorber mounted in the steering linkage (common on trucks/4x4s) that dampens road shock and reduces steering shimmy.

The shaft assembly connecting the steering wheel to the steering gear, usually with a collapsible feature for crash safety.

A flexible coupling in the steering shaft that lets the column change angle while still transmitting rotation.

Increased steering effort in both directions; causes include low power-steering fluid, a worn pump, a loose belt, or low tire pressure.

The vehicle drifting and needing constant correction; causes include worn linkage, low caster, or unequal tire pressure.

Free play in the steering wheel before the wheels move; usually worn tie-rod ends, idler/pitman arm, or gearbox wear.

The vehicle holding a steered direction after a turn instead of returning; often a binding strut mount or upper bearing.

A whine that rises and falls with steering effort; classically a low fluid level, air in the system, or a failing pump.

The amount the steering wheel turns before the road wheels move; excessive play means wear in the gear or linkage.

A coiled ribbon connector in the steering column that keeps the airbag and steering-wheel controls connected as the wheel turns.

Power steering that provides more assist at low speed (parking) and less at high speed for road feel.

Setting the sector-shaft (over-center) preload in a recirculating-ball gearbox to remove excess play without binding.

A flexible rubber boot that protects the inner tie-rod end and rack from dirt and moisture; a torn boot leads to wear.

Measuring the force needed to turn the wheel (often with a spring scale) to confirm proper power-assist operation.

The belt that drives the power-steering pump; a loose or glazed belt causes hard steering and a squeal.

The valve in a hydraulic gear that directs pressurized fluid to assist in the direction the driver is turning.

Bushings that secure the steering rack to the body/subframe; worn bushings cause a clunk and vague steering.

On both rack-and-pinion and recirculating-ball systems, front toe is adjusted at the tie-rod sleeves.

The output shaft of a recirculating-ball gearbox that the pitman arm is splined to.

The input gear in a recirculating-ball box that the steering shaft turns; ball bearings recirculate along its threads.

A side-to-side oscillation felt in the steering wheel, usually from tire imbalance, a bent wheel, or worn linkage.

An adjustable steering column that changes wheel angle and reach for driver fit.

Using a gauge to verify the pump produces specified pressure and the system holds it, diagnosing a weak pump or restriction.

A pull constantly tugs one direction (alignment/tire); wander drifts both ways and needs constant correction (worn linkage/low caster).

The lower steering shaft linking the column to the gear; worn U-joints in it cause a clunk or notchy steering feel.

Greasing serviceable tie-rod ends, ball joints, and idler arms (where fittings exist) to extend joint life.

Resistance or catching in the steering travel; can come from a tight gear adjustment, a seized joint, or a damaged column.

The tank that holds power-steering fluid and lets the system draw and return fluid; a low level causes a whine and hard steering.

Removing trapped air after service by cycling the steering lock-to-lock so the pump stops whining and assist is consistent.

Shaking each joint with the wheels supported to feel for play in tie-rod ends, idler arm, and pitman arm.

A recirculating-ball layout with a pitman arm, idler arm, center link, and two adjustable tie rods forming a parallelogram.

Bolts and bushings securing the gear to the frame/subframe; loose mounts cause clunks and vague steering.

The tendency of the steering to return to center after a turn, provided largely by positive caster.

Checking for play and a torn boot; a loose outer end causes toe change, wander, and uneven tire wear.

A clunk when turning or over bumps can be a worn U-joint, loose rack mount, or worn linkage joint.

The signature ASE format: judge each technician's statement separately as true or false, then choose A only, B only, both, or neither.

A suspension unit combining the shock absorber and a structural member, with the coil spring around it; the upper mount often carries the steering pivot bearing.

A hydraulic damper that controls spring oscillation so the tire stays on the road. Worn shocks cause float, nose dive, and cupped tire wear.

A spring that supports vehicle weight and absorbs bumps. A sagging or broken coil lowers ride height and changes alignment angles.

A stack of curved steel plates, mainly on truck rear axles, that supports load and locates the axle.

A spring that resists twisting; used on some front suspensions, with ride height adjusted by an anchor bolt.

A suspension arm (upper and/or lower) that locates the wheel and connects it to the frame through bushings and a ball joint.

A pivoting connection between the control arm and steering knuckle that lets the wheel move up/down and steer. A worn one clunks, wanders, and wears tires.

A ball joint that carries vehicle weight; checked with a dial indicator against the wear spec, with the load supported correctly.

A ball joint that does not carry weight; checked for any play by feeling for movement.

A built-in feature (such as a grease-fitting boss that recedes) showing when a ball joint is worn beyond spec.

A rubber or polyurethane bushing cushioning the control-arm pivot; worn bushings cause clunks, alignment drift, and wander.

A bar connecting left and right suspension that twists in turns to resist body roll. Worn links or bushings cause a clunk over bumps.

The link connecting the sway bar to the suspension; a worn or broken link causes a rattle/clunk and more body roll.

The upper mounting that secures the strut to the body and often houses the bearing the strut pivots on for steering.

The bearing in the upper strut mount that lets the strut rotate as the wheel steers; binding causes memory steer or a creak.

The seat and rubber isolator that locate the coil spring and quiet it; a damaged isolator causes a creak or clunk.

A rubber/foam stop that limits suspension travel and prevents metal-to-metal bottoming during a hard compression.

A rod that locates the lower control arm fore-and-aft; a worn strut-rod bushing causes a clunk under braking and caster change.

Pushing down hard on a corner and releasing; a good shock stops the body after about one rebound, a worn one bounces two or more times.

Excessive front-end dip during braking, a classic sign of worn front shocks or struts.

A continuing up-and-down motion after a bump, indicating worn dampers that no longer control the spring.

The designed distance between the body/frame and the ground; incorrect ride height (sagged springs) throws off camber and caster.

The vehicle's measured height at normal load; measured before alignment because it affects the angles.

A suspension using air springs (bags) and a compressor to support load and, on some systems, adjust ride height automatically.

Dampers whose firmness the vehicle adjusts electronically for ride and handling, often with a selectable mode.

A replaceable damping unit inside a serviceable strut housing, replacing the worn internals without the whole strut.

A tool that safely compresses a coil spring to remove or install it on a strut; required because the spring stores dangerous energy.

The bearing that lets the wheel hub spin freely; a worn bearing causes a growling noise that changes with speed and play at the wheel.

A sealed, pre-set hub-and-bearing unit replaced as a whole; common on modern vehicles in place of serviceable bearings.

Rocking the tire top-to-bottom (12 and 6 o'clock) to feel for looseness that points to a worn bearing.

A shock or strut with the coil spring mounted over it as one assembly, allowing ride-height/preload adjustment on some designs.

The upper locating arm in a short-long arm (SLA) suspension; works with the lower arm to control camber through travel.

The main lower locating arm that carries much of the suspension load and the lower ball joint.

An independent design with unequal-length upper and lower control arms, giving good camber control in travel.

A spring that has weakened and lost height, lowering ride height and altering camber/caster; replace as a pair.

The component holding the wheel bearing/hub that pivots to steer; a bent spindle shows as unequal included angle.

A clunk over bumps usually traces to a worn ball joint, control-arm bushing, sway-bar link, or strut mount.

Often a dry or worn bushing, strut bearing, or ball joint; lubrication or replacement is the fix.

The structure that mounts the engine, lower control arms, and steering rack; a shifted cradle changes alignment.

A lateral link that locates a solid axle side-to-side; a worn track-bar bushing lets the axle shift and causes wander.

The rubber bushing that mounts the sway bar to the frame; when worn it rattles and lets the bar move.

Oil running down the shock/strut body condemns the unit; the seals have failed and damping is lost.

A design where each wheel moves independently, improving ride and tire contact compared with a solid axle.

A single beam connecting both wheels; simple and strong, common on truck rear axles, but one wheel's motion affects the other.

Unwanted toe change as the suspension moves up and down, from worn parts or improper geometry, causing darting over bumps.

Replacing a strut changes camber/caster on many designs, so a wheel alignment is required afterward.

A shock only damps motion; a strut also structurally locates the wheel and carries the spring and steering pivot.

A growl or hum that changes with speed and may change when turning; worn bearings also create play at the wheel.

Replacing the whole pre-set hub-bearing assembly rather than repacking; common on modern vehicles.

Clunks, alignment drift, wander, and uneven tire wear; cracked or collapsed rubber confirms it.

The geometry that makes the inside wheel turn more sharply than the outside in a turn so both track without scrubbing.

Jounce is upward compression, rebound is downward extension; bump stops and dampers control the limits.

Suspension geometry that resists nose-dive under braking and rear squat under acceleration for a more level ride.

The inward or outward tilt of the wheel viewed from the front. Excess positive wears the outer tire edge; excess negative wears the inner edge.

The top of the wheel tilts outward. Too much positive camber wears the outer edge of the tire.

The top of the wheel tilts inward. Too much negative camber wears the inner edge of the tire.

The forward or rearward tilt of the steering axis viewed from the side. Positive caster aids straight-line stability and steering return; no direct tire wear.

The steering axis tilts rearward at the top. Improves high-speed stability and self-centering, at the cost of slightly heavier steering.

The steering axis tilts forward at the top. Lightens steering but reduces stability and return, allowing wander.

Whether the front edges of the wheels point inward (toe-in) or outward (toe-out) viewed from above. The most wear-sensitive angle; set last.

The front edges of the wheels point toward each other. A small amount compensates for forces that try to spread the wheels while driving.

The front edges of the wheels point away from each other; used as toe-out-on-turns for cornering geometry, but static toe-out causes instability.

A saw-tooth wear pattern across the tread caused by incorrect toe dragging the tire sideways as it rolls.

The direction the rear axle actually points relative to the vehicle centerline. A non-zero angle makes the steering wheel off-center and the vehicle dog-track.

The line bisecting the rear toe; a four-wheel alignment sets front toe to this line to keep the steering wheel centered.

When the rear wheels don't follow the fronts because of a thrust-angle error, so the vehicle moves slightly sideways.

The inward tilt of the steering axis viewed from the front; a built-in, non-adjustable angle used with the included angle to find bent parts.

The sum of SAI and camber. If camber differs side-to-side but the included angle is equal, a part is bent (spindle or strut).

The distance between where the steering axis and the tire centerline meet the road; affects steering feel and the pull from a low tire.

A condition where one front wheel sits farther back than the other, usually from collision damage or worn parts.

The geometry (Ackermann) that makes the inside wheel turn sharper than the outside in a corner; a wrong reading suggests a bent steering arm.

A steady pull goes toward the side with more positive camber or less positive caster; a tire can also cause a pull.

Swap the front tires side-to-side; if the pull moves with the tire, it's a tire (radial) pull, not the alignment.

An alignment that measures all four wheels and sets front toe to the rear thrust line; needed when the rear toe is off.

Adjusting only the front wheels; acceptable when the rear is non-adjustable and the thrust angle is within spec.

Caster first, then camber, then toe last — because changing caster or camber changes toe.

Setting front toe with the steering wheel held straight so the wheel is centered when the vehicle tracks straight.

Checking tire condition/pressure, ride height, and all steering/suspension joints before measuring — a worn part fails an alignment.

The manufacturer's target angles (and tolerances) for camber, caster, and toe that the technician aligns to.

Eccentric cams, shims, slotted mounts, or moving the strut/control arm — depends on the suspension design.

Shims, eccentric cams, or moving the strut rod/control arm fore-and-aft, depending on the suspension.

Turning the tie-rod sleeves to bring toe to spec; equal length on each side keeps the steering wheel centered.

The alignment-machine sensor head mounted to the wheel that reads camber and caster against the targets.

The maximum the wheels can turn; turntables (turn plates) measure it during the alignment.

The side-to-side difference in camber or caster; too much cross value causes a pull.

The lift and rotating plates that let the wheels move freely while the heads measure the angles.

Driving the vehicle to confirm it tracks straight, returns to center, and the steering wheel is level.

Using SAI and included angle: equal SAI but unequal camber/included angle means a bent strut or spindle, not an adjustment.

Caster is a directional-stability angle, so it affects pull and return but not tread wear directly the way camber and toe do.

Wandering, light steering, and poor return to center; the vehicle feels darty and unstable at speed.

Sagged springs change camber and caster, so ride height must be correct before aligning.

Even a small toe error drags the tire sideways every mile, making toe the biggest single cause of fast tire wear.

Memory steer = vehicle holds a turned direction (binding part); torque steer = pull under acceleration on FWD from unequal driveshaft forces.

Camber affects how the tread contacts the road; large camber tilts the contact patch and wears one edge.

Caster is not direct-read; the alignment machine calculates it by turning the wheels a set amount and reading camber change.

Toe at the rear axle; unequal rear toe creates a thrust-angle error, an off-center steering wheel, and rear tire wear.

Camber at the rear wheels; excess wears the rear tire edges and, if adjustable, is corrected with shims or cams.

Toe — because adjusting caster or camber changes toe, so toe is always set after them.

Feathered tire wear with the sharp edges pointing outward, plus a slight loss of cornering bite.

Feathered wear pointing inward and a darty, unstable straight-line feel.

With a side-to-side camber difference, the vehicle pulls toward the wheel with the more positive (outward-leaning) camber.

With a caster difference, the vehicle pulls toward the side with the less positive (lower) caster.

Brake pull appears only while braking (a brake fault); alignment/tire pull is constant.

A built-in radial-tire defect that makes the tire pull like a cone; swapping the tire side-to-side moves the pull.

Alignment specs give a preferred target and an acceptable range; aim for preferred and keep side-to-side differences small.

The flexible rubber component that grips the road, supports load, and cushions bumps; the only contact between vehicle and road.

Wear on both outer edges with a good center indicates under-inflation — low pressure lets the shoulders carry the load.

Wear in the center with good shoulders indicates over-inflation — high pressure bulges the center to carry the load.

Scalloped dips around the tread from the tire bouncing — a sign of worn shocks/struts, a bent wheel, or severe imbalance.

Adding weights so the assembly spins without vibration. An out-of-balance front tire causes a steering-wheel shimmy at highway speed.

A heavy spot causing an up-and-down (tramp) vibration; corrected by balancing in a single plane.

A heavy spot off the centerline causing a side-to-side shimmy; corrected by balancing in two planes.

Moving tires to different positions in a recommended pattern to even out wear and extend tire life.

A tire with reinforced sidewalls that lets the vehicle be driven a limited distance and speed after losing air pressure.

Tire Pressure Monitoring System — sensors that warn the driver when a tire's pressure drops significantly below the recommended value.

Direct uses a pressure sensor in each wheel; indirect infers low pressure from wheel-speed (ABS) data differences.

The molded info giving size, load index, speed rating, and construction (such as P215/65R15) used to select the correct tire.

A number on the sidewall indicating the maximum weight a tire can safely carry at its rated pressure.

A letter on the sidewall indicating the maximum sustained speed a tire is designed to handle.

A tire whose body plies run radially (across the tread) with stabilizing belts; the standard modern construction for ride and tread life.

Raised bars in the tread grooves; when the tread is worn level with them (about 2/32 inch), the tire is legally worn out.

Installing a tire on a wheel with a tire machine, lubricating the bead and seating it without exceeding the bead-seat pressure limit.

Inflating a mounted tire so its beads snap onto the rim's bead seats; never exceed the recommended seating pressure.

Tightening wheel lug nuts to the specified value in a star (crisscross) pattern to seat the wheel evenly and avoid warped rotors.

The pattern for tightening lug nuts so clamping force is even across the wheel and the wheel/rotor doesn't distort.

Pressure is set when the tires are cold; driving heats the air and raises pressure, so check before driving.

The vehicle's recommended tire pressure on the door-jamb sticker — use this, not the max pressure on the tire sidewall.

Shaving a small amount of rubber to make a tire perfectly round, correcting a vibration from an out-of-round tire (rarely done today).

How much a tire or wheel wobbles (radial = up/down, lateral = side-to-side); excess runout causes a vibration balancing can't fix.

Balancing that also presses a roller on the tire to find stiffness variation, curing vibrations simple balancing misses.

A wheel with excess runout (often from a pothole) that causes a vibration or wobble; it cannot be balanced out and must be repaired or replaced.

Recommended schemes (such as forward-cross or rearward-cross) that move tires to equalize wear based on drive type and tire directionality.

A tire designed to roll one way (arrow on the sidewall); it can only be rotated front-to-back on the same side, not crossed.

The spare's inflation should be checked regularly (when checking the other tires) so it is usable in an emergency.

Both shoulders = under-inflation; center = over-inflation; one edge = camber; feathered = toe; cupping = worn shocks/bent wheel.

A vibration that rises smoothly with speed and smooths out is usually tire balance or runout, not the engine.

Repairs are allowed only in the tread area within size limits; sidewall and shoulder punctures are not repairable.

The DOT date code gives the week/year of manufacture; tires age and should be inspected/replaced regardless of tread after several years.

Measuring tread depth (or using a tread-depth gauge); about 2/32 inch remaining means the tire is worn out.

Clip-on weights go on the rim flange and adhesive weights inside the barrel; placement comes from the balancer.

Aligning the tire's high spot to the wheel's low spot (often paint dots) to minimize runout and vibration.

Over-tightening lug nuts can warp brake rotors and stretch studs; always torque to spec.

Checking lug-nut torque again after a short drive, because seating can let them relax, especially on alloy wheels.

A full-size spare matches the road tires; a compact (temporary) spare is for limited distance and reduced speed.

A tire with a softer compound and aggressive sipes for grip in cold and snow; identified by a mountain-snowflake symbol.

Pressure must match the load; under-inflation overheats and wears the shoulders, raising the risk of a blowout.