158. How do you test the hydraulic brakes for leaks?
Detailed Explanation
While stationary, pump three times, then hold firm pedal pressure for five seconds. Pedal movement indicates a possible leak or other problem; repair before driving.
Official reference: Oregon Commercial Driver Manual, Section 2.1.5: Hydraulic LeaksCorrect Answer: Pump the brake pedal three times, then apply firm pressure to the pedal and hold for five seconds. The pedal should not move.
Why This Matters on the CDL Test
Separate leak testing from stopping-action testing.
How to Remember It
Three pumps, five-second hold.
Answer Review
Sustained pressure checks whether the pedal holds.
Why the other answers are weaker
- Drive 20 mph and slam on the brakes.Not the stationary leak test.
- Drive slowly and pump the brake pedal. Make sure it doesn't hit the floor.Omits the required sustained hold.
Test-Day Checklist
- Read the question once for the topic, then read it again for the exact CDL action being tested in General Knowledge.
- Eliminate answers that sound convenient but skip an inspection, warning sign, or safety step.
- Say the correct rule out loud before moving on so you can recognize it when the exam changes the wording.
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255. Your vehicle has hydraulic brakes. When traveling on a level road, you press the brake pedal and find that it goes to the floor. Which of these statements is true?
95. You are testing the stopping action of service brakes on a hydraulic system. Which of these can mean there is a problem?
How can you check for a leak in hydraulic brakes?
How should hydraulic brakes be tested for leaks?
130. You are checking your brakes and suspension system for a pre-trip inspection. Which of these statements is true?
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