Hydraulic System: Description and Operation

Hydraulic Brake Actuation

CAUTION: 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.

This vehicle is equipped with a feed or adjustable brake pedal actuated dual brake system.
The brake pedal is connected to the power brake booster by the brake master cylinder push rod.
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 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.

Adjustable Brake Pedal
The vehicle has an optional adjustable bake pedal to increase driver comfort. The bake pedal position is changed in phase with the accelerator pedal. The system is adjusted by pressing the dash mounted switch that powers the drive motor mounted on the accelerator pedal assembly. The two-way motor operates backward (away from the driver) or forward (toward the driver) to adjust the accelerator pedal directly and the brake pedal through the drive cable attached to the brake pedal assembly
The dual brake system is split front and rear with the front wheel brakes comprising of one circuit and the rear wheel brakes, the other circuit.

Brake Fluid

WARNING: Use of any other then approved DOT 3 or DOT 4 brake fluid 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 IS 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-19542-AB or equivalent meeting Ford specification ESA-M6C25A. If DOT 3 is not available, use DOT 4 brake fluid meeting Ford specification SAE-J-1704-DOT 4.
^ 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 use contaminated brake fluid.

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.
^ ABS brake master cylinder will not be overhauled, due to internal adjustments which require extensive special tools and fixtures. Service is made by replacement only.

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 Pressure Control Valve
The brake pressure control valve proportions the pressure to the rear brakes. Brake force proportioning is integrated into the Anti-Lock Brake System (ABS) Module.

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 correctly 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.
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.