BC Transit – Air Brake Course

Mechanical Release of the Park Brake (Caging the Spring)
On “piggy-back” park brake systems such as the ones we’ve
looked at, it may be necessary to release the park brake after an
emergency application due to some sort of air system failure. Here,
the caging bolt has been inserted into the park brake chamber
through the access hole previously described. The operator would
simply turn the bolt until the park brake spring . is compressed and
the brakes are released.
Caging Bolt inserted into
spring brake chamber
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