Home › CDL Practice Tests › Air Brakes Questions › Question 125
When parking a bobtail tractor (no trailer) on a grade, what secures it?
- A.Its own spring (parking) brakes, set by pulling the yellow knob, plus chocks as added security on a grade
- B.The trailer supply knob alone
- C.Only the transmission gear with brakes released
- D.The steering wheel lock
Correct answer
A. Its own spring (parking) brakes, set by pulling the yellow knob, plus chocks as added security on a grade
Why
Bobtailing removes the trailer system but the tractor's spring brakes work the same way. Setting them, and chocking on grades, is the complete parking routine for the tractor alone.
Manual topic: Air Brakes - Spring Brakes and Parking Brakes · From the Air Brakes practice bank (AB-125).