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Automotix DIY provides automotive consumers and do it yourselfers; the most comprehensive repair information about 1991 GMC S15 Jimmy car and truck
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BRAKE SERVICE PROCEDURES FOR 1991 GMC S15 Jimmy AUTOMOBILES
Includes anti-lock brakes, disc, drum, power and hydraulic brake services diagnostics and procedures for domestic and imported 1991 GMC S15 Jimmy cars and light trucks from 1990+.
POWER BRAKE UNITS, GENERAL MOTORS -> Bendix Brake Boosters -> TROUBLESHOOTING -> ACCUMULATOR LEAK-DOWN, SYSTEM DOES NOT HOLD CHARGE -> GRABBY BRAKES OR BOOSTER CHATTERS/PEDAL VIBRATES -> SLOW BRAKE PEDAL RETURN
Vehicle: 1991 GMC S15 Jimmy 4.3 V6 GAS
SLOW BRAKE PEDAL RETURN
- Excessive seal friction in booster.
- Faulty spool action.
- Restriction in return line from booster to pump reservoir.
- Damaged input rod end.
GRABBY BRAKES OR BOOSTER CHATTERS/PEDAL VIBRATES
- Faulty spool action caused by contamination in ...
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BRAKE SERVICE PROCEDURES FOR 1991 GMC S15 Jimmy AUTOMOBILES
Includes anti-lock brakes, disc, drum, power and hydraulic brake services diagnostics and procedures for domestic and imported 1991 GMC S15 Jimmy cars and light trucks from 1990+.
DISC BRAKES, GENERAL MOTORS -> Bendix Single Piston Sliding Caliper -> CALIPER SERVICE -> ASSEMBLE -> DISASSEMBLE -> INSTALLATION -> REMOVAL
Vehicle: 1991 GMC S15 Jimmy 4.3 V6 GAS
REMOVAL
- Siphon two-thirds of brake fluid from master cylinder reservoir serving front disc brakes.
- Raise vehicle, support on jack stands and remove front wheels.
- Bottom the caliper piston in bore. Insert a screwdriver between inboard shoe and piston, then pry piston back into bore. The piston can also be bottomed in the bore with a large C-clamp, Fig. .
- Remove support key retaining screw.
- Drive caliper support key and spring from steering knuckle with a suitable drift and hammer, Fig. .
- Lift caliper from anchor plate and off rotor, Fig. . Hang caliper from coil spring with wire. Do n...
CLICK HERE TO GET FULL ACCESS TO 1991 GMC S15 Jimmy BRAKE SERVICE PROCEDURES
BRAKE SERVICE PROCEDURES FOR 1991 GMC S15 Jimmy AUTOMOBILES
Includes anti-lock brakes, disc, drum, power and hydraulic brake services diagnostics and procedures for domestic and imported 1991 GMC S15 Jimmy cars and light trucks from 1990+.
ANTI-LOCK BRAKES, GENERAL MOTORS -> Four Wheel Anti-Lock Brake System -> DESCRIPTION
Vehicle: 1991 GMC S15 Jimmy 4.3 V6 GAS
This braking system Fig. is designed to reduce the occurrence of wheel lock-up during severe braking conditions. To accomplish this function, the system regulates hydraulic brake line pressure by using an Electronic Hydraulic Control Unit (EHCU) module. This control module has two types of valves. Isolation valves which maintain pressure to each front wheel separately and rear wheels combined. Dump valves which dump pressure to each front wheel separately and rear wheels combined. These valves are controlled by a microcomputer which is part of the EHCU module. During a severe brak...
CLICK HERE TO GET FULL ACCESS TO 1991 GMC S15 Jimmy BRAKE SERVICE PROCEDURES
BRAKE SERVICE PROCEDURES FOR 1991 GMC S15 Jimmy AUTOMOBILES
Includes anti-lock brakes, disc, drum, power and hydraulic brake services diagnostics and procedures for domestic and imported 1991 GMC S15 Jimmy cars and light trucks from 1990+.
POWER BRAKE UNITS, GENERAL MOTORS -> Bendix Brake Boosters -> HYDRO-BOOST II -> BLEEDING BOOSTER -> CLEANING & INSPECTION -> DESCRIPTION -> DISASSEMBLE & ASSEMBLE
Vehicle: 1991 GMC S15 Jimmy 4.3 V6 GAS
DESCRIPTION
Hydro-Boost II is an hydraulically operated power brake booster. The hydraulic brake booster consists of an open center spool valve and an hydraulic cylinder combined into a single housing. The power steering pump provides the hydraulic fluid pressure to operate both the power brake booster and the power steering gear.
A dual master cylinder is bolted to the brake booster and is operated by a pushrod projecting from the booster cylinder bore.
The Hydro-Boost II also has an accumulator system which stores sufficient fluid under pressure to provide one power assisted brake...
CLICK HERE TO GET FULL ACCESS TO 1991 GMC S15 Jimmy BRAKE SERVICE PROCEDURES
BRAKE SERVICE PROCEDURES FOR 1991 GMC S15 Jimmy AUTOMOBILES
Includes anti-lock brakes, disc, drum, power and hydraulic brake services diagnostics and procedures for domestic and imported 1991 GMC S15 Jimmy cars and light trucks from 1990+.
DRUM BRAKES, GENERAL MOTORS -> Drum Brake Service -> Adjustments -> 1990-91 CHEVROLET & GMC C & K SERIES -> AUTOMATIC APPLY PARKING BRAKES -> CABALLERO & EL CAMINO -> CHEVROLET & GMC FULL SIZE TRUCKS & VANS EXCEPT 1990-91 C & K SERIES -> CHEVROLET ASTRO VAN & GMC SAFARI VAN -> CHEVROLET S/T 10 & GMC S/T 15, OLDSMOBILE BRAVADA -> CONTROL ROD, ADJUST -> Duo-Servo Brakes -> Lever Type -> LUMINA (APV), SILHOUETTE & TRANS SPORT -> MANUAL PARKING BRAKES -> Non-Servo Brakes -> Pedal Type -> Propeller Shaft Type -> SERIES 10-30/1500-3500 -> SERVICE BRAKES -> TRACKER
Vehicle: 1991 GMC S15 Jimmy 4.3 V6 GAS
SERVICE BRAKES
These brakes have self-adjusting shoe mechanisms that assure correct lining-to-drum clearances at all times. The automatic adjusters operate only when the brakes are applied as the vehicle is moving rearward or when the car comes to an uphill stop.
Although the brakes are self-adjusting, an initial adjustment is necessary after the brake shoes have been relined or replaced, or when the length of the adjusting screw has been changed during some other service operation. Refer to "Installation" for this procedure.
Frequent usage of an automatic transmission forward range to h...
CLICK HERE TO GET FULL ACCESS TO 1991 GMC S15 Jimmy BRAKE SERVICE PROCEDURES
BRAKE SERVICE PROCEDURES FOR 1991 GMC S15 Jimmy AUTOMOBILES
Includes anti-lock brakes, disc, drum, power and hydraulic brake services diagnostics and procedures for domestic and imported 1991 GMC S15 Jimmy cars and light trucks from 1990+.
POWER BRAKE UNITS, GENERAL MOTORS -> Delco-Moraine Brake Boosters -> POWER BRAKE UNIT, Replace -> 1990-91 C & K SERIES -> ASTRO & SAFARI VAN -> CABALLERO & EL CAMINO -> FULL SIZE EXCEPT 1990-91 C & K SERIES -> LUMINA APV, SILHOUTTE & TRANS SPORT -> S/T 10 & 15 & BRAVADA
Vehicle: 1991 GMC S15 Jimmy 4.3 V6 GAS
CABALLERO & EL CAMINO
- Remove vacuum hose from check valve and master cylinder retaining nuts.
- Pull master cylinder forward so it clears mounting studs and move to one side. Support cylinder to avoid stress on hydraulic lines.
- Remove power unit to dash nuts.
- Remove brake pedal pushrod retainer and disconnect pushrod from pin.
- Remove power brake unit from vehicle.
- Reverse procedure to install.
ASTRO & SAFARI VAN
- Disconnect master cylinder from power brake unit.
- Disconnect power brake unit pushrod from brake pedal.
- Remove power brake unit retaining nuts and the power brake unit.
- Rev...
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