1990 Ford E-350 Econoline Brake Service (ONLINE REPAIR MANUALS)

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...

Make sure booster rubber reaction disc is properly installed as shown in Fig. , if the master cylinder pushrod is removed or accidentally pulled out. A dislodged disc may cause excessive pedal travel and extreme operation sensitivity. The disc is black compared to the silver colored valve plunger that will be exposed after pushrod and front seal are removed. The booster unit is serviced as an assembly and must be replaced if the reaction disc cannot be properly installed and aligned, or if it cannot be located within the unit itself.

• Disconnect battery ground cable.
• Disconn...

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...

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...

REMOVAL

• Raise and support vehicle.
• Remove hub cap, then wheel and tire assembly.
• On vehicles with full-floating axles, remove brake drums 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 drums as follows:
• Remove brake drum retaining nuts.
• Remove brake drum. If brake lining is d...