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CDL Pre-Trip Inspection Practice Test 2026: 30 Pass/Fail Questions

Skills & Training Jan 11, 2026
CDL Pre-Trip Inspection Practice Test 2026: 30 Pass/Fail Questions
Verified Updated for 2026 Exams

Don't just read the guide. Test yourself with the actual questions likely to appear on your CDL test.

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You've memorized the Checklist. You know the names of the parts. But can you answer the examiner's specific questions about defects?

The Pre-Trip Inspection isn't just about pointing; it's about knowing what constitutes a failure. If a belt has 1 inch of play, is it good or bad? If a tire has 3/32" tread, is it legal?

Take this quiz to find out if you are ready for the real thing.

1. Engine & Under the Hood

1. You are checking the serpentine belt. You push on it and it deflects 1 inch. Is this acceptable?
A. Yes, up to 1 inch is fine.
B. No.
Correct Answer: B (No).
The Standard: Belts should have no more than 3/4 inch of play. 1 inch is too loose and indicates a defect. It could slip and cause the water pump or alternator to fail.
2. When checking the coolant level, you should:
A. Remove the radiator cap immediately.
B. Inspect the reservoir sight glass or remove the cap only when the engine is cool.
C. Wait for the engine to overheat.
Correct Answer: B.
Never remove a radiator cap on a hot engine; pressurized steam can burn you. Use the sight glass if available.

2. Wheels & Tires (High Failure Rate)

3. You are inspecting a front steer tire. The tread depth measures 3/32 of an inch. Is this legal?
A. Yes, the minimum is 2/32.
B. No, the minimum is 4/32.
C. Yes, as long as the sidewalls are good.
Correct Answer: B (No).
Steer tires require a minimum of **4/32 inch** tread depth in every major groove. Drive and trailer tires only require **2/32 inch**. You would be placed Out-of-Service for this.
4. Can you use re-grooved or re-treaded tires on the steer axle?
A. Yes.
B. No.
Correct Answer: B (No).
Bus drivers and truck drivers are prohibited from using regrooved, recapped, or retreaded tires on the front wheels (steer axle) for safety reasons.

3. Brakes & Suspension

5. Brake linings (pads) must not be worn dangerously thin. What is the typical minimum thickness?
A. 1/2 inch.
B. 1/4 inch.
C. 1 inch.
Correct Answer: B (1/4 inch).
Generally, brake shoes should not be worn thinner than 1/4 inch at the center. Any thinner, and you risk metal-on-metal contact, which leads to brake failure.

4. Coupling System

6. After coupling, there should be how much space between the upper and lower fifth wheel?
A. 1 inch.
B. No space.
C. 2 inches.
Correct Answer: B (No space).
There must be **no daylight** between the apron (trailer bottom) and the skid plate (5th wheel). If there is space, the trailer is not sitting flat and could disconnect or damage the kingpin.

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The #1 starting point. Covers vehicle inspections & basic road safety rules.

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Conclusion

If you missed any of these, you are not ready for the road test. The examiner will ask you specifics. Go back to the Checklist and memorize the numbers: 4/32, 2/32, 3/4 inch play, no daylight.

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