1990 Ford E-250 Econoline Brake Service (ONLINE REPAIR MANUALS)

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...

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...

Normal hydro-boost units will produce certain noises that current technology cannot correct. These noises occur when brake pedal is manipulated in a manner not associated with everyday braking habits. Normal operating noise can be a hissing, clunk, click or a chatter.

If above normal pedal efforts are applied, the hydra-boost unit will emit hissing noises. These noises will be particularly noticeable with the vehicle motionless and will increase in intensity as pedal efforts increase and system operating temperatures increase. Loud hissing noises at or below normal pedal effo...

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...

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...

Normal hydro-boost units will produce certain noises that current technology cannot correct. These noises occur when brake pedal is manipulated in a manner not associated with everyday braking habits. Normal operating noise can be a hissing, clunk, click or a chatter.

If above normal pedal efforts are applied, the hydra-boost unit will emit hissing noises. These noises will be particularly noticeable with the vehicle motionless and will increase in intensity as pedal efforts increase and system operating temperatures increase. Loud hissing noises at or below normal pedal effo...