Brake Master Cylinder: Description and Operation

Brake Master Cylinder
The brake master cylinder is a dual piston type. The brake master cylinder operates as follows:
- When the brake pedal is pressed, pressure is applied by mechanical linkage to the primary and secondary piston.
- Brake master cylinder pistons apply hydraulic pressure to the 2 diagonal hydraulic circuits.
- The anti-lock brake system (ABS) brake master cylinder cannot be overhauled, due to internal adjustments which require extensive special tools and fixtures. The repair is made by installing a new master cylinder only.

The brake master cylinder consists of:
- brake master cylinder fluid reservoir
- brake master cylinder body

Brake Master Cylinder Reservoir

NOTE: The brake master cylinder and brake master cylinder reservoir are replaced as an assembly. The reservoir cannot be replaced separately form the brake master cylinder.

The brake master cylinder reservoir:
- is mounted to the brake master cylinder.
- holds fluid supply for each brake master cylinder hydraulic piston.
- provides visual maximum and minimum fluid level markings.
- contains the brake master cylinder fluid level indicator switch.

The brake master cylinder fluid level indicator switch can be checked by putting a magnetic probe against the inside of the reservoir to activate the indicator switch.