Brakes (Handbrake operation): Description and operation (page 2 of 2)

The handbrake operates on both rear discs via two rear cables, a compensator and an intermediate cable which connects to the handbrake lever.

As the handbrake lever is applied, movement is transmitted through the intermediate cable to the compensator which, in turn, transmits movement to the two rear cables. Each rear cable pulls on a lever on a rear caliper. Rotational movement of the lever is changed to linear movement by the plunger which is forced out of its location by its inclined seating. The plunger contacts the push rod which, in turn, pushes the piston down its bore and forces the brake pads into contact with the disc.

Automatic adjustment of the pads is carried out by operation of the footbrake. With the brake pedal released, the piston is stationary in its bore and the adjuster nut is held against a cone seating inside the piston by the compression spring.

When the brake pedal is pressed, fluid pressure forces the piston down its bore and the compression spring causes the adjuster nut to follow. Initially the nut remains against its cone seating and just takes up the clearance between the push rod and its own thread and if piston movement is within this tolerance no automatic adjustment needs to take place.

Further movement of the piston moves the cone seating away from the adjuster nut. This allows the compression spring to rotate the adjuster nut along the push rod thread until it again contacts the cone seating.

This extending action of the push rod assembly maintains adjustment of the handbrake mechanism.

When fluid pressure is released, the piston moves back and re- establishes the clearance between the push rod thread and the adjuster nut thread.