Caging the brakes releases the brakes and prevents operation of the trailer
braking system. When the brakes have been caged, the trailer should only be
moved under emergency circumstances and then only with extreme caution
and at very low speeds.
The spring inside the brake chamber is under very high pressure. Do not loosen
or remove any nuts or bolts from the brake chamber except the caging bolt and
its associated hardware. Failure to follow this warning may result in serious
This procedure is used to manually release the brakes in the event that the
air supply to the trailer has been lost or interrupted. This procedure should
be performed only under extreme circumstances when the vehicle must be
Place blocks under trailer wheels to prevent trailer from rolling during procedure.
Remove the dust cover (3) from the caging bolt keyhole (2) in the center of the spring brake
If the inside of the spring brake chamber is clogged with mud, sand, or dirt, do not
proceed with the caging procedure unless the chamber can be cleared. Notify Unit
Maintenance if chamber cannot be cleared.
Visually inspect the inside of the spring brake chamber (4) for mud, sand, or dirt.
Remove nut (5) and washer (6) from the side of the spring brake chamber (4) and remove
caging bolt (1).