Home › CDL Practice Tests › Combination Vehicles Questions › Question 131
Why is using only the trailer hand valve for routine slowing and stopping a bad practice?
- A.The hand valve uses no air, so the trailer tanks will overfill
- B.The hand valve locks the steering axle whenever it is used
- C.Braking with the trailer alone can overheat and wear the trailer brakes, upset the balance of the combination, and help start a trailer skid
- D.Routine hand valve use disconnects the fifth wheel locking jaws
Correct answer
C. Braking with the trailer alone can overheat and wear the trailer brakes, upset the balance of the combination, and help start a trailer skid
Why
The hand valve is meant for testing trailer brakes and for limited, careful use, not as the main brake. Relying on it makes the trailer do all the work of holding back the whole combination, which wears its brakes and can pull it out of line.
Manual topic: Combination Vehicles - Skids and Jackknifing · From the Combination Vehicles practice bank (CV-131).