Hydraulic System: Description and Operation
Hydraulic Brake ActuationCAUTION: Blistering or swelling of rubber brake components may indicate contamination of the brake fluid by a petroleum based substance. Contaminated rubber components in the hydraulic brake system must be replaced and the entire hydraulic brake system must be flushed with clean brake fluid to prevent recontamination.
The vehicle is equipped with a brake pedal actuated dual brake system. The system consists of the following:
- brake pedal (fixed or adjustable)
- power brake booster
- brake master cylinder
- front disc brake calipers
- rear disc brake calipers
- brake tubes and hoses
- Anti-Lock Brake System (ABS) components (if so equipped)
The dual brake system is split front and rear with the front wheel brakes comprising one circuit and the rear wheel brakes, the other circuit.
Brake Fluid
WARNING: Use of any brake fluid other than approved DOT 3 will cause permanent damage to brake components and will render the brakes inoperative.
WARNING: Brake fluid contains polyglycol ethers and polyglycols. Avoid contact with eyes. Wash hands thoroughly after handling. If brake fluid contacts eyes, flush eyes with running water for 15 minutes. Get medical attention if irritation persists. If taken internally, drink water and induce vomiting. Get medical attention immediately.
CAUTION: Brake fluid is harmful to painted or plastic surfaces. If brake fluid is spilled onto a painted or plastic surface, immediately wash it with water.
Use clean, fresh Ford High Performance DOT 3 Motor Vehicle Brake Fluid C6AZ- 1 9542-AB or equivalent meeting Ford specification ESA-M6C25A.
- Do not reuse brake fluid drained or bled from the system.
- Do not use brake fluid that has been stored in an open container.
- Do not mix different types of brake fluid.
The brake pedal is connected to the power brake booster, which is connected to the brake master cylinder. When the brake pedal is depressed, brake fluid is pushed from the master cylinder through the metal tubing and flexible hoses to the rear disc brake calipers and the front disc brake calipers. The brake fluid enters the rear disc brake calipers, forcing the rear disc brake caliper pistons outward against the brake pads. The brake pads press against the braking surface on the brake discs. The front disc brake caliper pistons are forced outward against the brake pads, and contact the braking surface of the brake discs and hub. When the brake pedal is released, the pressure is relieved, returning the brake caliper pistons and the brake shoes and linings to the unapplied position.
The dual brake system is split front and rear with the front wheel brakes comprising one circuit and the rear wheel brakes, the other circuit.
The ability of a brake system to stop the vehicle is dependent on the available traction. Brake Master Cylinder
The brake master cylinder is a dual piston type. The brake master cylinder operates as follows:
- When the brake pedal is depressed, pressure is applied by mechanical linkage to the primary and secondary piston.
- Brake master cylinder pistons apply hydraulic pressure to the two hydraulic circuits.
The brake master cylinder consists of:
- brake master cylinder reservoir
- brake master cylinder body
Brake Master Cylinder Reservoir
NOTE: Whenever the brake master cylinder reservoir is removed from the brake master cylinder, new grommets must be installed.
The brake master cylinder reservoir:
- is mounted to the brake master cylinder.
- holds fluid supply for each brake master cylinder hydraulic piston.
- provides visual fluid level markings.
- contains the brake master cylinder fluid level sensor.
Brake Tubes and Hoses
CAUTION: Never use copper tubing. It is subject to fatigue, cracking and corrosion which could result in brake tube failure.
Steel tubing is used throughout the brake hydraulic system. All brake tube fittings must be properly double flared to provide strong leakproof connections. When bending the tubing to fit the underbody or rear axle contours, be careful not to kink or crack the tube, allow the tube to contact any other component, or come within 50.8 mm (2 inch) of the exhaust system.
If a section of brake tube is damaged, the entire section must be replaced with a tube of the same type, size, shape and length.
When replacing hydraulic brake tubing, hoses or connectors, tighten all connections securely. After replacement, bleed the brake system.