CDL Combination Vehicles TestCombination Vehicle Air BrakesEasy
A driver is inspecting the air brake system on a combination vehicle. They notice that the brake chambers on the trailer are operating correctly, and the pushrod travel is within limits. What is the maximum allowable pushrod travel for a Type 30 brake chamber?
- A1 inch
- B2.5 inches
- C2 inches
- D1.5 inches
Show answer & explanationAnswer & explanation
Correct answer: C. 2 inches
Proper pushrod travel is crucial for effective braking. Exceeding the maximum allowable travel indicates that the brakes are out of adjustment and need to be serviced immediately to prevent brake failure.
Why the other options are wrong
- A. This is too little travel for a Type 30 brake chamber, suggesting the brake might be over-adjusted or incorrectly measured.
- B. This amount of pushrod travel is excessive for a Type 30 brake chamber, indicating a significant brake adjustment issue.
- D. This is also less than the maximum allowable travel for a Type 30 brake chamber, which would still be considered acceptable if the actual limit is higher.
Pushrod Travel Limit (Type 30)
The maximum allowable extension of the pushrod from a Type 30 brake chamber is 2 inches before the brake is considered out of adjustment.
- Indicates brake adjustment status
- Excessive travel reduces braking power
- Must be checked during pre-trip inspection
Memory trick: Remember 'Two for Type 30' to keep your brakes fine and dandy.