Brake Master Cylinder: Description and Operation

The master cylinder is a dual circuit unit designed for use in diagonally split hydraulic systems. With a diagonally split system, the left front and right rear brake are on one hydraulic circuit, while the right front and left rear are on the other.

Threaded into the rear brake lines are integral brake proportioning valves, which limit fluid pressure to the rear brakes after a predetermined rear brake pressure has been reached. These valves are used to minimize the occurrence of rear wheel lock-up when brakes are applied and vehicle is lightly loaded in the rear.

A brake fluid level switch, located in the brake fluid reservoir (attached to the master cylinder), is also provided. The switch will activate the RED BRAKE telltale lamp (located on instrument panel) should the brake fluid level become low. After the brake fluid level is corrected and a moderately high brake pedal force is applied, the RED BRAKE telltale lamp should go off.