Where Is the Master Cylinder Located?

The master cylinder is usually found on the driver side of the engine bay, fixed to the firewall near the brake pedal. It typically sits below the brake fluid reservoir. In cars with power-assisted brakes, the master cylinder might be connected to the brake booster.

The master cylinder is just about always mounted to the front side of a vacuum or hydraulic booster that applies pressure to the master cylinder’s piston. That booster is activated by a push rod connecting to the brake pedal.

The brake master cylinder turns the brake pedal’s force into hydraulic pressure that applies the brake linings, whether they be shoes or pads, generating friction that slows down your car. In a way, the cylinder is like the heart of the brakes.

Inside the brake cylinder are two separate chambers and a piston that moves through the chambers.

Tips on How to Access the Master Cylinder

Always wear protective gear when accessing the master cylinder. Put on work gloves to protect your bare skin from direct contact with brake fluid. Wear protective eyewear to keep your eyes safe from injury caused by exposure to brake fluid, fumes, and other hazards.

1. Using a tool of your choice, draw the fluid out of the master cylinder.
2. Disconnect the brake lines from the master cylinder using line wrenches.
3. Disconnect the fluid level sensor connector.
4. Remove the nuts at the flanges holding the master cylinder to the booster.
5. Remove the master cylinder.

Exert care when disconnecting the brake lines and working on the brake line clamps. The brake lines might crack if handled roughly, leading to a brake fluid leak. You’ll need to replace a damaged line before replacing the master cylinder.