1991 Ford E-350 Econoline Brake Service (ONLINE REPAIR MANUALS)

The rear anti-lock brake system constantly monitors rear wheel speed. In the event of an impending rear brake lockup, the system regulates hydraulic pressure to the rear brakes, preventing total lockup when the brakes are applied and thereby reducing the possibility of skidding.

The system consists of a yellow warning light on the instrument panel, an electro-hydraulic rear anti-lock brake system (RABS) valve mounted on the frame rail behind the crossmember, a speed sensor mounted on the rear drive axle, an exciter ring mounted on the differential case and a comput...

When working on or around brake assemblies, care must be taken to prevent breathing asbestos dust, as many manufacturers incorporate asbestos fibers in the production of brake linings. During routine service operations precautions should be taken to minimize exposure. Do not sand or grind brake linings unless suitable local exhaust ventilation equipment is used to prevent excessive asbestos exposure.

• Wear a suitable respirator approved...

To check adjustment of pushrod, fabricate a gauge and position it against master cylinder mounting ...

BRAKE DRUMS

Any time brake drums are removed for brake service, braking surface diameter should be checked with a suitable micrometer at several points to determine if they are within the safe oversize limit stamped on the brake drum outer surface. If braking surface diameter exceeds specifications, the drum must be replaced. If braking surface diameter is within specifications, drums should be cleaned and inspected for cracks, scores, deep grooves, taper, out of round and heat spotting. If drums are cracked or heat spotted, they must be replaced. Minor scores should be remove...

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...

Bleed primary and secondary hydraulic brake systems separately, bleeding the longest line first on each system. Do not allow reservoir to run dry during bleeding operation. Never reuse fluid that has been drained from the hydraulic system.

• Loosen master cylinder to hydraulic line nuts and wrap shop cloths around tubing below fitting to absorb escaping brake fluid.
• Depress brake pedal slowly forcing air trapped in master cylinder out at fitting.
• Hold pedal down and tighten fittings, then release brake pedal. Releasing brake pedal before fittings are tightened will allow air to ...