1991 Ford Mustang Brake Service (ONLINE REPAIR MANUALS)

• Inspect components for damage and unusual wear. Replace as necessary.
• Inspect wheel cylinders. Boots which are torn, cut, or heat damaged indicate need for wheel cylinder replacement. Fluid spilling from boot center hole, or wetness around wheel cylinder ends indicates cup leakage and need for wheel cylinder replacement.A small amount of fluid is always present and is considered normal, acting as a lubricant for the cylinder pistons.
• Inspect backing ...

DESCRIPTION

The proportioning valve (when used),Fig. , provides balanced braking action between front and rear brakes under a wide range of braking conditions. The valve regulates the hydraulic pressure applied to the rear wheel cylinders, thus limiting rear braking action when high pressures are required at the front brakes. In this manner, premature rear wheel skid is prevented.

TESTING

When a premature rear wheel slide is obtained on a brake application, it usually is an indication that the fluid pressure to the rear wheels is above the 50% reduction ratio for the rear line ...

Complaints about power brake operation should be handled as if two separate systems exist. Check for faults in the hydraulic system first. If it is satisfactory, start inspecting the power brake circuit. For a quick check of proper power unit operation, press the brake pedal firmly and then start the engine. The pedal should fall away slightly and less pressure should be needed to maintain the pedal in any position.

Another check begins with installation of a suitable pressure gauge in the brake hydraulic system. Take a reading with the engine off and the power unit not opera...

FRONT & REAR SPLIT SYSTEMS

When the brake pedal is depressed, both the primary (front brake) and the secondary (rear brake) master cylinder pistons are moved simultaneously to exert hydraulic fluid pressure on their respective independent hydraulic systems. The fluid displacement of the two master cylinders is proportioned to fulfill the requirements of each of the two independent hydraulic brake systems,Figs. and .

If a failure of a rear (secondary) brake system should occur, initial brake pedal movement causes the unrestricted secondary piston to bottom in the mas...

• Inspect components for damage and unusual wear. Replace as necessary.
• Inspect wheel cylinders. Boots which are torn, cut, or heat damaged indicate need for wheel cylinder replacement. Fluid spilling from boot center hole, or wetness around wheel cylinder ends indicates cup leakage and need for wheel cylinder replacement.A small amount of fluid is always present and is considered normal, acting as a lubricant for the cylinder pistons.
• Inspect backing ...

The caliper assembly consists of a pin slider caliper housing, inner and outer shoe and lining assemblies and a single piston,Figs. and . The caliper slides on two pins which also act as attaching bolts between caliper and the combination anchor plate and spindle. The outer brake shoe and lining assembly is longer than the inner brake shoe and lining assembly. Inner and outer shoe and lining assemblies are attached to the caliper by spring clips riveted to the shoe surfaces. The inner shoe is attached to the caliper by installing the spring clip to the inside of the caliper piston. T...