Manual release for parking brake in automatic transmission has a manually operated hydraulic pump to provide hydraulic pressure to release the brake

摘要

A parking brake (1) for an automatic transmission is held in the blocking position by a spring. It is released by hydraulic pressure from the hydraulic control system for the transmission. If the hydraulics fails, or if the vehicle is to be towed, a pump lever (16) is pressed to operate a hydraulic pump (3) to provide sufficient hydraulic pressure to release the brake. This can require several operation of the lever. The hydraulic hoses from the manual pump are flexible to isolate the manual pump from pressure variations in the system hydraulic when operating normally.