Construction and Operation

CONSTRUCTION

Front Brake:

The front system consists of:
^ Four piston hydraulic caliper (2)
^ Ventilated brake disc (2)

Rear Brakes:

The rear system consists of:
^ Two piston hydraulic caliper (2)
^ Solid brake disc (2)

Tandem Hydraulic Braking:

OPERATION
On application of the brake pedal the servo unit, which is directly coupled to the master cylinder, transfers increased pedal pressure to the master cylinder primary piston 'A' causing the piston to move forward past the by-pass port 'P' to establish rear brake line pressure in chamber 'B'. Pressure from the primary cylinder return spring 'C' and rear brake line pressure force the secondary piston 'D' forward past the by-pass port 'P' to establish front brake line pressure in chamber 'E' -

Front and rear braking pressures enter the P.D.W.A. unit at ports 'F' and 'G', act on either end of the shuttle valve 'H' and travel to front and rear calipers via ports 'J' and 'K'. Should a fall in front or rear braking pressure occur the resultant pressure imbalance causes displacement of the shuttle valve, which in turn operates the switch 'L' and illuminates a warning light in the instrument panel. In order to reset the displaced shuttle valve the cause of fall in brake line pressure must first be established and rectified. During bleeding of the brake system which follows rectification the shuttle valve automatically resets, and extinguishes the warning light. Brake pressure entering the caliper 'M' forces the pistons 'T' out to act on the friction pads 'U' which in turn clamp the brake disc 'V' - On release of the brake pedal, brake line pressure collapses which allows the piston seals 'W' to retract the pistons into the caliper. Withdrawal of the pistons into the caliper is just sufficient for the friction pads to be in a relaxed position away from the disc. This sequence provides automatic adjustment for brake pad lining wear.


Should the brake servo unit become inoperative front and rear braking systems will still operate but at a greatly reduced brake line pressure. A divided brake fluid reservoir 'R' ensures that in the event of fluid loss to front or rear brake systems one pair of brake calipers will at all times be operative. The fluid level indicator 5' provides visual warning to the driver should the level of fluid in the reservoir fall to an unsatisfactory level.


1983 M.Y. SPECIFICATION

Brakes - All Models

The brake system pressure differential warning actuator (P.D.W.A.) unit has been deleted.

NOTE: This deletion in no way affects the performance of the braking system as the conventional split system is retained.

All steel brake pipes on 1983 model year cars will be plastic coated. This will improve the corrosion resistance of the pipe work.