System PartsQuestion 10 of 60
In a dual air brake system, before driving you should let air pressure build to at least what level in both systems?
a.50 psi
b.75 psi
c.90 psi
d.100 psi
Explanation
You should wait until the air pressure builds to at least 100 psi in both the primary and secondary systems before driving. Building to the normal operating range ensures the brakes have enough air to function. Driving with too little pressure is unsafe because braking capacity is reduced.
Practice all 60 questions free — no signup required.
Related questions on this topic
- Spring brakes on a truck are held in the released position by what?
- What happens to the spring brakes when air pressure drops to a very low level (for example, 20 to 45 psi)?
- Why do heavy vehicles use a dual air brake system?
- What is the purpose of the supply pressure gauge in the cab?
- What does the application pressure gauge show?
- What does the brake pedal (foot valve) do in an air brake system?
Last reviewed: · editorial process
PrepPass Editorial Team · Verified against CDL Air Brakes Knowledge Test · How we review