Five free practice questions on brake, drivetrain, steering and chassis checks: content area D of the ASE T8 Preventive Maintenance Inspection (PMI) test, 22 of its 50 scored questions (44%). They are in the ASE format: four options, one best answer. Answer each one before opening the explanation. No account, no email.
01The questions
-
A truck's air dryer purges when the governor sends its unloader signal. During a PMI, the technician watches a test gauge as air pressure builds with the engine idling. Which event marks the governor's cut-out pressure on the gauge?
- The low-air warning lamp and buzzer going off
- The idle speed dipping as the compressor loads up
- The supply reservoir safety valve starting to hiss
- The air dryer's purge exhaust giving a burst
Show the answer
D. Correct. At cut-out the governor sends reservoir air to the compressor unloader, and on this truck the same signal opens the dryer's purge valve, so the purge blast marks the moment pressure stops rising. The gauge reading at that instant is recorded as cut-out.
Why not the others
A. The low-air warning clears at its own setting, far below governor cut-out, as pressure first builds. Cut-out comes much later, when the governor unloads the compressor and the dryer purges.
B. The compressor takes load when it starts pumping again, which happens at cut-in, not cut-out. At cut-out the compressor unloads and the dryer gives its purge blast.
C. The safety valve is set well above a working cut-out and opens only when pressure goes too high. Hearing it during build-up means the governor or unloader has failed to stop the compressor.
ID T8-D-004 · Task T8-D-2 (ASE task list)
-
A replacement spring brake chamber comes with every drain hole in its housing plugged. After it is mounted, which drain hole does its manufacturer have opened?
- The one at the top, so the chamber can breathe
- The one at the lowest point, facing down
- Every hole, so no water can collect anywhere
- None of them, since all must stay plugged
Show the answer
B. Correct. The drain hole at the bottom of the mounted chamber lets condensation drain out, while the plugs left in the other holes keep road spray and dirt out. Which hole that is depends on how the chamber is clocked on the axle, so it is checked on every installed chamber.
Why not the others
A. A hole at the top lets spray and wash water run in rather than out. The manufacturer opens the hole at the lowest point, facing down, so condensation drains.
C. Opening every hole lets road spray and dirt in through the upper holes. Only the hole at the lowest point is opened, so moisture drains while the rest of the housing stays sealed.
D. With every hole plugged, condensation trapped in the housing has no way out and corrodes the parts inside. The hole at the lowest point is opened.
ID T8-D-019 · Task T8-D-14 (ASE task list)
-
A truck's air-shifted PTO is engaged by a dash switch that powers a solenoid valve, which sends air to the PTO's shift cylinder. The PTO will not engage. Any of these could be the cause EXCEPT:
- a blown fuse in the PTO switch circuit.
- a worn U-joint on the PTO driveshaft.
- a kinked air line to the shift cylinder.
- a leaking seal in the PTO shift cylinder.
Show the answer
B. Correct. The PTO driveshaft is downstream of the PTO and plays no part in shifting it into gear; a worn U-joint there shows as noise, vibration or looseness during PMI. A dead switch circuit, a leaking shift cylinder or a blocked air line all stop the PTO engaging.
Why not the others
A. With the fuse blown the solenoid valve gets no power and never sends air to the shift cylinder. This could be the cause.
C. A kinked line blocks the air the solenoid valve sends, so the cylinder cannot shift the PTO. This could be the cause.
D. A leaking shift cylinder seal lets the air escape before it can move the shift fork. This could be the cause.
ID T8-D-038 · Task T8-D-45 (ASE task list)
-
Under 49 CFR 393.75, a truck may not be operated on a tire with any of these conditions EXCEPT:
- a cut that exposes the sidewall ply cords.
- a sidewall bulge from a ply separation.
- an audible leak from a nail in the tread.
- shallow weather checking on the sidewall.
Show the answer
D. Correct. Fine surface cracks from age and sunlight that expose no ply or belt material are not among the conditions the rule lists (exposed ply or belt, separation, flat or audible leak, a cut to the ply). They are recorded so the tire can be watched and replaced as it ages.
Why not the others
A. The rule bars operating on a tire with a cut deep enough to expose ply or belt material, so this tire must come off before the truck runs.
B. The rule bars operating on a tire with any tread or sidewall separation, and a bulge is how a separation shows, so this tire must come off.
C. The rule bars operating on a tire that is flat or has an audible leak, so this tire is repaired or replaced before the truck runs.
ID T8-D-057 · Task T8-D-59 (ASE task list) · 49 CFR 393.75
-
A straight truck has a fixed-caster, self-steering lift axle mounted ahead of its drive axle. What is done with that axle before the truck backs up?
- It is lowered so it carries part of the load in reverse
- It is raised, or its wheels are locked straight
- Its wheels are left free to steer, as they do going forward
- Its air springs are dumped so the drive axle takes the load
Show the answer
B. Correct. A self-steering axle's wheels trail behind their kingpins (caster) so they follow the truck going forward; in reverse that same caster swings them the wrong way, scrubbing tires and straining the axle and suspension. So it is lifted before backing, or locked straight on an axle built with a lock.
Why not the others
A. Lowering a self-steering axle with its steering free while backing lets its caster swing the wheels to the side. It is raised, or locked straight if it has a lock.
C. The caster that makes the wheels follow going forward turns them the wrong way in reverse. The axle is raised, or locked straight if it has a lock.
D. Dumping the load air springs alone may leave the wheels on the ground and free to swing. The axle is raised clear, or locked straight if it has a lock.
ID T8-D-071 · Task T8-D-70 (ASE task list)
02Answer key
| Question | Answer |
|---|---|
| Q1 | D |
| Q2 | B |
| Q3 | B |
| Q4 | D |
| Q5 | B |
03What area D covers
Everything below the cab falls in Area D. That means air and hydraulic brakes, from governor settings and leakage tests to linings, slack adjusters and calipers; the clutch, transmission, driveshafts, axles and PTO, with their fluid changes and oil samples; steering, wheel bearings, tires, wheels and studs; and the suspension, frame, fifth wheel, pintle hook, lift gate and rear impact guard.
The ASE test specification calls this content area “Frame and Chassis”. It carries 22 of the 50 scored questions, 44% of the test.
- Record governor settings, build-up time and air leakage
- Test low-air warnings, tractor protection and parking brakes
- Check linings, drums, rotors and slack adjuster stroke
- Inspect hydraulic brake lines, calipers, boosters and fluid
- Check clutch, transmission, driveshafts and axles; take oil samples
- Measure steering lash, kingpin wear and wheel bearing end play
- Inspect tires, wheels, studs and nuts; record tread and pressure
- Inspect suspension, frame, fifth wheel, pintle hook and rear guard
04What the questions turn on
Isolate what the check proves
A check proves only the part it isolates. Each low-air switch is proven by draining its reservoir with the other full, since a joint drop lets one switch hide a dead one. The parking brake hold test is made with the service pedal released.
Find where the motion is lost
Lost motion is where one part moves and the next waits. If the input shaft turns at once but the Pitman arm waits, the wear is inside the steering gear. A drag link end moving ahead of its steering arm is worn.
Temperature changes the reading
A hot tire reads above its cold pressure, so air is never let out to match; it is rechecked cold. A transmission dipstick is read on the band for the sump temperature, and a cold level already in the hot band shows an overfill.
Held until it is repaired
Some findings hold the vehicle until repaired. A crack from a disc wheel's hand hole means a new wheel. Paint marks showing a tire and rim turned together on a spoke wheel mean the rim slipped, so it is reseated and its clamps torqued.
05The other content areas
The T8 test has five content areas. Each has its own page of free questions:
The ASE T8 Preventive Maintenance Inspection (PMI) 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, not affiliated with or endorsed by ASE (the National Institute for Automotive Service Excellence). Our questions are original, written from ASE’s published test specifications and task lists and other public sources. They are not actual ASE test questions and not recalled or “brain dump” questions. ASE is a trademark of its owner, and we never use the ASE logo. Standards and service information are cited, not reproduced.