Examkin

Question

Difficulty: EasyBrake System Components Inspection

At an en-route inspection stop, a driver checks the pushrod travel on a vehicle fitted with manual slack adjusters. After securing the vehicle with wheel chocks and releasing the parking brakes, what is the maximum distance the pushrod should move when pulled firmly by hand?

  1. A
    It should move at least 2 inches2\text{ inches} to ensure proper drum clearance
  2. It should not move more than about 1 inch1\text{ inch}Answer
  3. C
    It should move no more than 14 inch\frac{1}{4}\text{ inch} with the parking brakes fully applied
  4. D
    It must not move at all when pulled by hand

Answer

It should not move more than about 1 inch1\text{ inch}
On a commercial motor vehicle equipped with manual slack adjusters, pushrod free play should not exceed approximately 1 inch when pulled firmly by hand with the parking brakes released and wheels safely chocked. Excessive movement indicates the brake is out of adjustment and may fail to stop the vehicle effectively.

Step-by-Step Solution

1
Chock the wheels and release the parking brakes to remove spring tension from the foundation brakes.
The brake pushrod and slack adjuster mechanism are freed for manual movement.
Pushrod free play cannot be measured while spring brakes are actively engaged.
2
Grasp the slack adjuster and pull firmly by hand to check pushrod stroke distance.
The pushrod moves outward until the brake shoes contact the drum.
Commercial vehicle safety standards specify that pushrod free play must not exceed approximately 1 inch on manual slack adjusters.

Key Concept

Manual slack adjuster pushrod travel limit during manual inspection
Estimated Time:45s
Rate this question

Topics

Brake System Components Inspection

More questions from this topic