1991 Ford Explorer Brake Service (ONLINE REPAIR MANUALS)

This brake booster is a hydraulically operated booster, receiving its power from the power steering system, Fig. . The power steering pump provides fluid pressure to operate both the brake booster and the power steering gear. This fluid pressure provides a variable power assist that is regulated by brake pedal applic...

RAIL SLIDER CALIPER

Removal

• Drain a small amount of brake fluid from master cylinder reservoir.
• Raise and support vehicle, then remove wheel and tire assembly.
• Install an eight inch C-clamp on caliper housing and tighten clamp to bottom piston(s) in cylinder bore(s), then remove clamp. Do not use screwdriver or other edged tool to pry piston(s) from rotor.
• Remove key retaining screw, then using a hammer and drift, drive out caliper support key and spring.
• On single piston calipers, push caliper downward against spindle, then rotate upper end upward and out of spindle assembly.
• On dua...

EXCESSIVE PEDAL TRAVEL

• Worn brake lining.
• Shoe and lining knock back after cornering or rough road travel.
• Piston and shoe and lining assembly not properly seated or positioned.
• Air leak or insufficient fluid in system or caliper.
• Loose wheel bearing adjustment.
• Damaged or worn caliper piston seal.
• Improper booster pushrod adjustment.
• Shoe out of flat more than .005 inch.
• Rear brake automatic adjusters inoperative.
• Improperly ground rear brake shoe and lining assemblies.

BRAKE ROUGHNESS OR CHATTER; PEDAL PUMPING

• Excessive lateral runout of rotor.
• Rotor excessively out of parallel.

EXCESSIVE P...

MASTER CYLINDER

The master cylinder consists primarily of a hydraulic cylinder, primary and secondary hydraulic pistons and a single or dual chamber fluid reservoir. The front brakes are connected to the primary outlet port(s) and are actuated by the primary piston assembly. The rear brakes are connected to the secondary outlet port and are actuated by the secondary piston assembly.

HYDRAULIC CONTROL VALVES

Combination Valve

This multi-function hydraulic control unit consists primarily of a pressure differential valve, brake lamp warning switch and a proportioning valve. A pressure diff...

BRAKE LININGS

Remove both front wheels and inspect the brake discs, calipers and linings. (Wheel bearings should be inspected at this time and repacked if necessary).

Do not get any oil or grease on the linings. It is recommended that both front wheel sets be replaced whenever a respective shoe and lining is worn or damaged. Inspect and, if necessary, replace rear brake linings also.

If the caliper is cracked or fluid leakage through the casting is evident, it must be replaced as a unit.

BRAKE ROUGHNESS

The most common cause of brake chatter on disc brakes is a variation in thick...

REMOVAL

• Raise and support vehicle.
• Remove wheel and tire assembly.
• On vehicles with full-floating axles, remove brake drum as follows:
• Loosen brake shoe adjustment screw.
• Remove rear axle retaining bolts and lock washers, axle shaft, and gasket.
• Remove wheel bearing locknut, lock washer, and adjusting nut.
• Remove hub and drum from axle.
• Remove brake drum to hub retaining screws, bolts, or bolts and nuts, then remove brake drum from hub.
• On vehicles with semi-floating axles, remove brake drum as follows:
• Remove brake drum retaining nuts.
• Remove brake drum. If brake lining is dragging on brake...