Home › CDL Practice Tests › Air Brakes Questions › Question 107
What is the danger of applying the parking (spring) brakes when the drums are extremely hot after a long descent?
- A.Hot drums make spring brakes permanently stronger
- B.Heat can damage the drums and related parts, and as parts cool and contract the hold can change; hot brakes should cool before parking brakes are set when possible
- C.There is no concern with heat and parking brakes
- D.The springs will melt instantly in all cases
Correct answer
B. Heat can damage the drums and related parts, and as parts cool and contract the hold can change; hot brakes should cool before parking brakes are set when possible
Why
Setting powerful spring force against overheated, expanded drums risks warping and cracking as the metal cools. Letting brakes cool first, and using chocks on grades, protects both the equipment and the hold.
Manual topic: Air Brakes - Spring Brakes and Parking Brakes · From the Air Brakes practice bank (AB-107).