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

Rotational movement of the caliper lever is changed to linear movement by a 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 disc brake pads is maintained by operation of the foot brake. 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 ring.

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 takes 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.

Manual adjustment of the handbrake cables is effected via the adjusting nut on the threaded intermediate rod bearing upon the compensator. See Adjustments.