System PartsQuestion 16 of 60
What controls the parking brakes on a vehicle with air brakes?
a.The foot brake pedal
b.A separate parking brake control valve
c.The supply pressure gauge
d.The trailer hand valve only
Explanation
On air brake vehicles, the parking brakes are set with a separate control valve, often a yellow diamond-shaped knob. Pulling the knob out applies the spring parking brakes, and pushing it in releases them. The parking brakes are held on by spring force, not air pressure.
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Related questions on this topic
- What does the brake pedal (foot valve) do in an air brake system?
- What is the function of the brake chamber and pushrod?
- What is the purpose of the slack adjuster?
- Why should you NOT use the parking brakes if the brakes are very hot, such as after coming down a steep hill?
- What is the trailer hand valve (trolley valve) used for?
- Why should the trailer hand valve NOT be used for parking?
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