BC Transit – Air Brake Course

Park Brake Emergency Functions...
4. When operating a vehicle where there is no emergency release
reservoir (most tractor-trailers and trucks) never go under the
vehicle to wind off (cage) the spring brakes without first
verifying that the vehicle cannot roll away when the brakes
release. Block the vehicle!
5. The effectiveness of the spring brakes is entirely dependent upon
brake adjustment. If your brakes are not properly adjusted, your
park brake may be unreliable or even useless. Remember to
check for slack brakes and set them up... OFTEN!!!
6. Applying the service brake when the park brake is applied can
damage the brake components. (push rods, slack adjusters.)
Therefore, never make full service applications when the park
brake is applied. This is known as compounding the brakes.
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