Five free practice questions on suspension systems: content area B of the ASE A4 Suspension & Steering test, 12 of its 40 scored questions (30%). They are in the ASE format: four options, one best answer. Answer each one before opening the explanation. No account, no email.
01The questions
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A replacement lower control arm bushing has open voids molded through its rubber on two opposite sides. Why does the manufacturer specify which way the voids must face when it is pressed in?
- The rubber is softer toward the voids than across them
- The voids drain water out of the bushing's outer sleeve
- The voids leave room for the rubber to swell as it heats up
- The voids must face the press to keep the rubber from tearing
Show the answer
A. Correct. The voids make the bushing soft in their direction and firm across them, so the arm can give fore and aft for a smoother ride while staying stiff side to side for steering response. Pressed in at the wrong angle, the arm moves the wrong way under load.
Why not the others
B. The voids are not drainage passages; the rubber is bonded to its sleeves. They tune how stiff the bushing is in each direction, which is why they must face the specified way.
C. The rubber needs no relief pockets for heat. The voids make the bushing softer in one direction than the other, and the arm's handling depends on where they point.
D. The installation tool bears on the bushing's sleeve, so the voids' position has nothing to do with tearing during pressing. They set the bushing's directional stiffness.
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A customer asks for the front of a car to be lowered by modifying the original coil springs. Technician A says cutting a coil off each spring makes the springs softer. Technician B says heating the springs with a torch to lower the car ruins the spring steel's temper. Who is right?
- A only
- B only
- Both A and B
- Neither A nor B
Show the answer
B. Correct. Technician B is right: heat destroys the heat treatment that gives spring steel its strength, so a heated spring sags and can break. Technician A is wrong, because removing a coil leaves fewer active coils, which makes the spring stiffer, and it also changes how the end seats. Springs built for the lower height are the proper repair.
Why not the others
A. Technician A is wrong: fewer active coils make a spring stiffer, not softer. Technician B is right, because torch heat ruins the spring steel's temper and the spring can sag or break.
C. Only Technician B is right. Torch heat ruins spring temper, but Technician A has the effect backwards: cutting a coil off leaves fewer active coils and raises the spring rate.
D. Technician B is right, because torch heat destroys the temper of spring steel. Technician A is wrong, since a spring with fewer active coils is stiffer, not softer.
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On a vehicle with electronic air suspension, the left front corner stays low after the engine starts while the other three corners rise to normal height. Any of these could be the cause EXCEPT:
- a kinked air line feeding the left front corner's air spring.
- an open circuit to the left front air spring valve.
- a left front air spring leaking faster than the compressor can restore its height.
- a left front height sensor that reads lower than actual.
Show the answer
D. Correct. A sensor that reports the corner lower than it is makes the module add more air, so the corner would rise, likely above normal height, rather than stay low. The other faults each keep air from building up in that spring.
Why not the others
A. This could cause it: air from the compressor cannot pass the kink, so that spring cannot fill while the others rise normally.
B. This could cause it: with no power reaching the corner's valve, it stays closed and the module cannot route air into that spring.
C. This could cause it: a leak larger than the compressor's output lets the air escape as fast as it arrives, so the corner never comes up.
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A rear coil spring sits on a rubber insulator in its lower seat and has another under its upper end. What is the main job of these insulators?
- Locating the axle from side to side in turns
- Controlling how fast the spring rebounds after bumps
- Raising the spring rate as the load on it grows
- Keeping road noise and vibration from the body
Show the answer
D. Correct. The insulators keep the steel coil ends off the steel seats, so road noise and vibration are not carried into the body and the coil ends cannot grind or creak on their seats. A missing insulator also lowers that corner by its thickness.
Why not the others
A. Side-to-side location comes from the track bar or lateral links. The insulators only cushion the spring ends in their seats to keep noise and vibration out of the body.
B. Rebound speed is controlled by the shock absorber's valving. The insulators are thin rubber pads that isolate the spring from its seats.
C. An insulator is a thin rubber pad and does not set or raise the spring's rate. Its job is to keep the steel spring off the steel seats so noise and vibration stay out of the body.
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Many rear shock absorbers carry a charge of pressurized nitrogen gas along with their hydraulic oil. What does the gas charge mainly do?
- It keeps the oil from foaming in use
- It carries part of the weight at ride height
- It stops the rod at full extension
- It cools the oil as it passes the valves
Show the answer
A. Correct. Pressurizing the oil keeps bubbles from forming in it as the piston moves fast over rough roads, so oil keeps flowing through the valves at the designed rate and damping does not fade.
Why not the others
B. The gas pushes the rod out with a small force, but the springs carry the vehicle's weight. The charge is there mainly to keep the oil from foaming so damping stays steady.
C. Full-extension travel is limited by the shock's internal rebound stop or a separate rebound bumper. The gas keeps the oil free of bubbles so damping stays steady.
D. Heat leaves through the shock's body to the air. The gas charge pressurizes the oil so it does not foam and lose damping.
02Answer key
| Question | Answer |
|---|---|
| Q1 | A |
| Q2 | B |
| Q3 | D |
| Q4 | D |
| Q5 | A |
03What area B covers
This content area covers the front and rear suspension and what holds it to the vehicle. Questions deal with ride height and ride quality, control arms, bushings and ball joints, coil springs, leaf springs and torsion bars, struts, shocks and their mounts, stabilizer bars and links, track bars and trailing arms, wheel bearings and hubs, electronic and air suspension, and subframe mounts.
The ASE test specification calls this content area “Suspension Systems Diagnosis and Repair”. It carries 12 of the 40 scored questions, 30% of the test.
- Diagnose suspension noise, handling and ride height
- Replace control arms, bushings and ball joints
- Service coil springs, leaf springs and torsion bars
- Replace struts, shocks, mounts and bump stops
- Inspect stabilizer bars, track bars and trailing arms
- Replace wheel bearings and hub assemblies
- Diagnose electronic and air suspension systems
- Inspect subframe mounts, bushings and bolts
04What the questions turn on
Unload the joint to check it
Ball joint play is checked with the joint unloaded. On a short-long arm suspension with the spring on the lower arm, the jack goes under the lower arm close to the ball joint, so the jack takes the spring's force and play can be measured.
No heat and no cutting
Heat destroys the heat treatment that gives spring steel its strength, and removing a coil leaves fewer active coils, which makes the spring stiffer. A chip in a spring's coating can rust and start a fatigue crack, so compressor jaws are padded or placed carefully.
Shock force follows piston speed
A hydraulic shock forces oil through valved orifices, so its resistance rises with piston speed and it adds little force while the suspension is still. It controls bouncing but does not hold the vehicle up; worn dampers let the body keep bouncing after bumps.
Follow the air
A compressor that runs steadily without raising the vehicle points to air escaping, such as through a stuck-open exhaust valve. A compressor that has full voltage and a good ground while commanded on, yet still will not run, has an internal fault.
05The other content areas
The A4 test has four content areas. Each has its own page of free questions:
The ASE A4 Suspension & Steering practice test page describes the full question bank. How these questions are written and checked: how our questions are made. Found a mistake? Tell us and we will fix it.
ToolboxPrep is an independent study site. It is not affiliated with or endorsed by ASE (the National Institute for Automotive Service Excellence). Our questions are original practice questions written to the published ASE test specifications; they are not actual test questions.