Disc Brake System & Drum Brake System GMC Jimmy Typhoon

MODEL IDENTIFICATION

Vehicle model can be identified by fifth character of Vehicle Identification Number (VIN), stamped on metal pad on top of left end of instrument panel, near windshield. See MODEL IDENTIFICATION table.

MODEL IDENTIFICATION

DESCRIPTION & OPERATION

Note. On vehicles with full-floating axle, axle shaft and hub must be removed to remove brake disc or drum. (Scheme 10)and (Scheme 11). On vehicles with semi-floating axle, brake drum can be removed without removing axle shaft.

Note. For information on Bendix Hydro-Boost see BENDIX HYDRAULIC BRAKE BOOSTER article in the BRAKES Section.

Note. Information in this article also applies to vehicles equipped with Anti-Lock Brake System (ABS); however, not all information on ABS is included in this article. See ANTI-LOCK BRAKE SYSTEM - REAR WHEEL or ANTI-LOCK BRAKE SYSTEM 4-WHEEL article in the BRAKES Section.

"P" Series Motorhome

On the automatic apply parking brake system, when shift lever is in Park, engine running, and manual parking brake foot lever in released position, fluid flows from steering gear to port SR on relay valve and out to port TW to the control valve supply port SC. (Scheme 1) Once the system is charged, pressure should range between 130-150 psi (9.1-10.5 kg/cm 2 ). Any excess fluid will be discharged through port "R" and back to the pump. The supply port or charge port SC is blocked off due to control valve position in Park mode.

Any previously pressure built-up in control valve flows through control valve out port EC back through the relay valve, triggering release of pressure from port "D" of relay valve through port ER to reservoir. (Scheme 1) This allows the spring controlled actuator to apply parking brake. The spring will apply brake by travelling as far as the brake adjustment demand requires to balance brake apply and spring force.

When valve is released from Park position, fluid charge at shift control valve port SC is diverted to port DC. The shift control port EC is blocked off. Fluid charge at relay valve port SR is diverted to port "D", pressurizing parking brake system and actuator. (Scheme 1) Fluid pressure working against the spring pressure in actuator releases parking brake.

The manual foot lever should still be applied whenever vehicle is shifted into Park. This will alert operator of need for adjustment in the parking brake system.

Note. All figures in this article are Courtesy of General Motors.

Schematic Of Automatic Parking Brake System ("P" Series Motorhome). Scheme 1

BRAKE SHOE ASSEMBLY

Some "C" and "K" Series vehicles are equipped with leading/trailing brakes, identified by adjuster screw hole in backing plate, located above horizontal centerline of rear axle. All other "C" and "K" Series vehicles and all other models are equipped with dual-servo brakes, identified by adjuster screw hole at bottom of backing plate.

Brake assembly consists of backing plate, brake shoes, return springs, automatic adjusting assembly and a wheel cylinder.

Automatic adjusting assembly consists of an actuator lever, return spring, actuator link, adjusting screw and spring. Automatic adjustment is accomplished through movement of actuating lever and secondary shoe.

Lumina APV, Silhouette & Trans Sport

Brake warning light is energized when ignition is on and parking brake is applied or when master cylinder fluid level is low. Brake warning light is not energized if hydraulic pressure is lost; system is not equipped with pressure differential switch.

Except Lumina APV, Silhouette & Trans Sport

Pressure differential warning switch in combination valve energizes brake warning light on instrument panel when front or rear brakes lose hydraulic pressure. After repairing failed side of hydraulic system, depress brake pedal with moderate to heavy pressure to hydraulically center the piston. This will turn off brake warning light.

CALIPERS

Front brakes are floating caliper or sliding caliper design. (Scheme 14)and (Scheme 15). Rear brakes are sliding caliper design. Caliper is attached to caliper mount. Caliper is mounted to steering knuckle or caliper adapter, depending on application. Caliper assembly slides back and forth in machined cut-outs.

Combination Valve (Except Lumina APV, Silhouette & Trans Sport)

System uses a combination valve to regulate brake system hydraulic pressure. Combination valve, located in brake lines between master cylinder and wheels, has 3 pressure control functions

1. Metering (or hold-off) section of valve limits pressure to front brakes until pressure of rear brake shoe retractor springs is overcome, then allows pressure to front brakes.
2. Proportioning section of valve allows input pressure to rise to predetermined level before allowing output pressure to rear brakes. This prevents rear wheel lock-up on vehicles with light rear wheel loads.
3. By-Pass section of valve ensures full system pressure is applied to rear brakes if front brakes loses hydraulic pressure (or if rear brakes lose hydraulic pressure, full pressure is applied to front brakes).

Combination valve also contains a pressure differential warning switch. See BRAKE WARNING LIGHT under DESCRIPTION & OPERATION .

Height-Sensing Proportioning Valve ("C" & "K" Series & "P" Series)

Valve senses vehicle load conditions through relative movement between rear axle and body. (Scheme 4)and (Scheme 5). As vehicle load increases (resulting in decreased vehicle height), valve allows higher pressure to rear brakes, resulting in optimum front-to-rear brake pressure balance.

Proportioning Valves (Lumina APV, Silhouette & Trans Sport)

System uses 2 proportioning valves, threaded into master cylinder, to regulate brake system hydraulic pressure. (Scheme 23)

Valves allow input pressure to rise to predetermined level before allowing output pressure to rear brakes. This prevents rear wheel lock-up on vehicles with light rear wheel loads. Valves also incorporate a by-pass feature which ensures full system pressure is applied to rear brakes if front brakes lose hydraulic pressure (or if rear brakes lose hydraulic pressure, full pressure is applied to front brakes).

BLEEDING BRAKE SYSTEM

Note. On vehicles with ABS, wait 15 seconds between pedal strokes when bleeding brake system. On vehicles with Hydro-Boost, check for air bubbles in power steering fluid reservoir. If air bubbles are present, bleed Hydro-Boost system before bleeding brake system. See BLEEDING HYDRO-BOOST SYSTEM in BENDIX HYDRAULIC BRAKE BOOSTER article in the BRAKES Section.

BLEEDING SEQUENCE

BLEEDING SEQUENCE

MASTER CYLINDER BLEEDING

Note. To prevent air from entering brake system, bench bleed master cylinder before installing.

1. Place master cylinder in soft-jawed vise. DO NOT overtighten vise. Install bleeder tubes in both outlets of master cylinder. (Scheme 2) Fill master cylinder reservoir. Ensure ends of bleeder tubes are submerged in brake fluid.
2. Using screwdriver or drift punch at end of master cylinder bore, press and release piston assembly until air bubbles are no longer present in fluid flow. Leave bleeder tubes installed on master cylinder. Install master cylinder.
3. Remove bleeder tubes. Connect brake lines at master cylinder. DO NOT fully tighten brake lines at this time. Slowly press brake pedal to floor and hold. Tighten brake lines. Release brake pedal. Bleed brake system. See «MANUAL BLEEDING»(/gmc/jimmy-typhoon/1992-1993/remont/mechanical-hydraulic/#disc-brake-system-drum-brake-system__manual-bleeding), «PRESSURE BLEEDING»(/gmc/jimmy-typhoon/1992-1993/remont/mechanical-hydraulic/#disc-brake-system-drum-brake-system__pressure-bleeding) or «VACUUM BLEEDING»(/gmc/jimmy-typhoon/1992-1993/remont/mechanical-hydraulic/#disc-brake-system-drum-brake-system__vacuum-bleeding).

Scheme 2

MANUAL BLEEDING

Note. Air tends to cling to caliper walls. When bleeding vehicles with disc brakes, lightly tap caliper to help remove air.

1. Fill master cylinder. Install bleeder hose to bleeder screw at first wheel to be serviced. See BLEEDING SEQUENCE under «BLEEDING BRAKE SYSTEM»(/gmc/jimmy-typhoon/1992-1993/remont/mechanical-hydraulic/#disc-brake-system-drum-brake-system__bleeding-brake-system) . Submerge other end of hose in glass jar partially filled with brake fluid.
2. Open bleeder screw 3/4 - 1 turn. Slowly press brake pedal to floor. Note fluid flow. Close bleeder screw. Release pedal. Repeat procedure until air bubbles are no longer present in fluid flow.

PRESSURE BLEEDING

Note. Air tends to cling to caliper walls. When bleeding vehicles with disc brakes, lightly tap caliper to help remove air. DO NOT use rigid clamp to position hold-off valve stem. This may damage valve assembly, causing brake failure.

1. Retain hold-off valve stem of combination valve using Valve Retainer (J-23709). (Scheme 3) This allows brake fluid to flow through combination valve and entire system during bleeding.
2. Clean master cylinder cap and surrounding area. Remove cap. With pressure tank at least 1/2 full, connect pressure bleeder to master cylinder with adapters. Attach bleeder hose to first bleeder valve to be serviced. See BLEEDING SEQUENCE under «BLEEDING BRAKE SYSTEM»(/gmc/jimmy-typhoon/1992-1993/remont/mechanical-hydraulic/#disc-brake-system-drum-brake-system__bleeding-brake-system).
3. Place other end of hose in glass jar partially filled with brake fluid so end of hose is submerged in fluid. Open release valve on pressure bleeder. Set pressure bleeder to 20-25 psi (1.4-1.8 kg/cm 2 ) or pressure specified by equipment manufacturer.
4. Open bleeder screw 3/4 - 1 turn and note fluid flow. Close bleeder screw when no air bubbles are present in fluid flow. Repeat procedure on remaining wheels in proper sequence.
5. Check brake pedal operation. Remove pressure bleeder. Remove valve retainer from hold-off valve. Refill master cylinder reservoir, if necessary.

Scheme 3

VACUUM BLEEDING

Note. Air tends to cling to caliper walls. When bleeding vehicles with disc brakes, lightly tap caliper to help remove air.

1. Fill master cylinder reservoir. Install vacuum bleed equipment to first bleeder valve to be serviced. See BLEEDING SEQUENCE under «BLEEDING BRAKE SYSTEM»(/gmc/jimmy-typhoon/1992-1993/remont/mechanical-hydraulic/#disc-brake-system-drum-brake-system__bleeding-brake-system) .
2. Open bleeder valve 3/4 - 1 turn. Press vacuum pump to draw fluid into reservoir jar until no air bubbles are present in fluid flow. Close bleeder screw. Repeat procedure on remaining wheels in sequence.

HEIGHT-SENSING PROPORTIONING VALVE

Note. If front wheel lock-up is experienced during braking when vehicle is near maximum GVWR, adjust height-sensing proportioning valve.

"C" & "K" Series

Ensure rear axle is hanging free and valve is securely bolted to frame when lever is attached to valve before height-sensing proportioning valve is adjusted. (Scheme 4)

"P" Series

1. Raise vehicle at frame rails, allowing rear axle to hang free. Remove nut and lever from valve shaft. (Scheme 5) Select appropriate adjustment gauge (available from manufacturer). Rotate valve shaft to permit installation of gauge.
2. Install gauge with flat on valve shaft indexed to flat on gauge, and tang on gauge inserted in valve mounting hole. Install lever (DO NOT pull lever onto shaft using nut). Install nut. Break off tang on gauge. Lower and test-drive vehicle.

Scheme 4

Scheme 5

PARKING BRAKE

Note. On all models except "C" and "K" Series with leading/trailing brakes, ensure rear brake shoes are adjusted before adjusting parking brake. See REAR BRAKE SHOES under ADJUSTMENTS .

Astro & Safari

1. Raise and support vehicle. Loosen parking brake cable adjusting nut. Apply parking brake pedal 2 notches from fully released position.
2. Tighten adjusting nut until left rear wheel can be turned rearward using 2 hands, but not forward. Release parking brake and ensure wheels rotate freely. Lower vehicle.

Apply parking brake pedal 3 notches from fully released position. Raise and support vehicle. Tighten parking brake cable adjusting nut until right rear wheel can be turned rearward but not forward. Release parking brake and ensure wheels rotate freely. Lower vehicle.

"C" & "K" Series With Leading/Trailing Brakes

1. Raise and support rear of vehicle. Remove rear wheels. Remove brake drums. Rotate parking brake adjusting screw until clearance between brake drum and shoes is .010-.020" (.25-.51 mm). Use brake drum diameter gauge to determine clearance.
2. Ensure stop on parking brake lever is in contact with edge of brake shoe web. If parking brake cable is holding stops off of shoe web, loosen cable adjusting nut. Tighten cable adjusting nut until lever stop begins to move off of shoe web.
3. Loosen cable adjusting nut until lever stop moves back toward lever stop and barely contacts the stop. Clearance should be no more than .020" (.51 mm) between lever stop and shoe web.
4. Install brake drums and wheels. Apply and release service brake pedal 30-35 times with normal pedal force, pausing about one second between pedal applications. Apply parking brake pedal 6 notches from fully released position.
5. Rear wheels should not be able to be rotated. Release parking brake and ensure wheels rotate freely. Lower vehicle.

"C" Series with Transmission-Mounted Parking Brake

1. Remove clevis pin from lever assembly. (Scheme 6) Apply parking brake pedal 4 notches from fully released position.
2. Using small length of cable or chain and a turnbuckle, install Spring Scale (J-35999) between lever assembly and vehicle frame. Tighten turnbuckle until spring scale indicates 50 lbs. (22.7 kg).
3. Loosen clevis nut (at cable end). Turn clevis until clevis pin slides freely into lever assembly with all slack removed from cable. Install clevis pin and retain with a cotter pin. Tighten clevis nut. Remove spring scale. Release parking brake.

Installing Spring Scale On Transmission-Mounted Parking Brake Assembly ("C" Series). Scheme 6

"C" & "K" Series With Dual-Servo Brakes, "G" Series & "P"

Series With Foot Pedal

Raise and support vehicle. Loosen parking brake cable adjusting nut. Apply parking brake pedal 4 notches from fully released position. Tighten adjusting nut until wheels rotate forward with moderate drag. Release parking brake and ensure wheels rotate freely. Lower vehicle.

"P" Series With Hand Lever

1. Raise and support rear of vehicle. Rotate adjusting knob on parking brake lever counterclockwise until it stops. Apply parking brake. Loosen parking brake cable adjusting nut.
2. Tighten adjusting nut until slight drag is felt when rotating rear wheels forward. Tighten adjusting knob on parking brake lever until definite snap-over-center pressure is felt when parking brake lever is applied. Release parking brake. Ensure wheels rotate freely. Lower vehicle.

"P" Series With Transmission-Mounted Parking Brake

1. Raise and support rear of vehicle. For preferred method of adjustment, perform steps 2) and 3). For alternate method of adjustment, perform step 4).
2. Remove drive shaft. Install parking brake drum over first rivet section of brake shoes. Insert .010" (.25 mm) shims between both shoes and drum, spaced 140-180 degrees apart.
3. Rotate adjuster screw until no clearance exists. Remove shims. Install drum and drive shaft. Drum should rotate freely with light drag.
4. Rotate adjuster screw through hole in backing plate until brake drum just locks up. Back off adjuster screw until drum spins freely with light drag. Lower vehicle.

"S" & "T" Series

1. Raise and support vehicle. Loosen parking brake cable adjusting nut. Apply parking brake pedal 2 notches (2WD) or 3 notches (Bravada and 4WD) from fully released position.
2. Tighten adjusting nut until wheels will not rotate forward without excessive force. Back off adjusting nut until slight drag exists when wheels are rotated forward. Release parking brake and ensure wheels rotate freely. Lower vehicle.

1. Disconnect parking brake control rod from control valve lever and transmission control equalizer. (Scheme 7) Place control valve lever in park position. Place transmission selector in Park.
2. Connect parking brake control rod to control valve lever. Loosen parking brake control rod jam nuts. Rotate rod as necessary to align hole at end of rod with hole in transmission control equalizer lever. Install and tighten bolt.

Adjusting Automatic Parking Brake Control Rod ("P" Series Motorhome). Scheme 7

1. Ensure parking brake is released. Raise and support vehicle. Remove rear wheels. Rotate adjusting screw until clearance between brake drum and shoes is .050" (1.27 mm). Use brake drum diameter gauge to determine clearance.
2. Install brake drum. Install wheels. Operate vehicle for several forward and reverse stops while firmly applying brakes. Repeat procedure until ample brake pedal reserve is obtained.

Brake shoe adjustment is accomplished by adjusting parking brake. See PARKING BRAKE under ADJUSTMENTS .

Except "C" & "K" Series With Leading/Trailing Brakes

1. Ensure parking brake is released. Raise and support vehicle. Knock out lanced area in backing plate with a punch (if not already removed) and remove from brake assembly.
2. Working through hole in backing plate, rotate adjusting screw until brake shoes expand and brake drums can just be turned by hand. Ensure drag is equal at both wheels. Back off adjusting screw 24 notches (Astro, Safari and "S" & "T" Series) or 33 notches (all others) at each wheel.
3. If heavy drag is present after adjusting screw is backed off 12 notches (Astro, Safari and "S" & "T" Series) or 15 notches (all others), check parking brake adjustment. See PARKING BRAKE under «ADJUSTMENTS»(/gmc/jimmy-typhoon/1992-1993/remont/mechanical-hydraulic/#disc-brake-system-drum-brake-system) . To complete procedure, install plug in backing plate. Check parking brake adjustment.

"C" & "K" Series With Cruise Control

Depress and hold brake pedal. Pull lever on stoplight switch back to its stop. (Scheme 8) Pull brake pedal against pedal stop. Release brake pedal. Switch is adjusted if brake lights do not come on with pedal released.

Except "C" & "K" Series With Cruise Control

Depress and hold brake pedal. Push switch forward until firmly seated in retaining clip. Pull brake pedal rearward against pedal stop (clicks can be heard as switch ratchets through retaining clip). Release brake pedal. Switch is adjusted if brake lights do not come on with pedal released.

Scheme 8

Electrical Circuit

Disconnect wire from switch terminal on combination valve. Connect wire to ground. Turn ignition on. If brake warning light does not come on, repair brake warning light bulb or wiring circuit. If light operates, brake warning light electrical circuit is okay.

Note. On Astro and Safari, system is not equipped with pressure differential switch.

Warning Light Switch

1. Fill master cylinder reservoir. Attach bleeder hose to bleeder screw at either rear wheel. Immerse other end of hose in container of brake fluid. Turn ignition on.
2. While depressing brake pedal, open bleeder screw (close bleeder screw before releasing pedal). On all models except Astro and Safari, if light comes on, go to step 3). If light does not come on, switch is defective; replace combination valve.
3. Close bleeder screw. Depress brake pedal with moderate to heavy pressure. If light goes out, switch is okay. If light stays on, switch is defective, replace combination valve. Repeat test on front brake system. System should function in same manner as rear.

AUTOMATIC PARKING BRAKE ("P" SERIES MOTORHOME)

Note. Adjust parking brake control rod after removing and installing control valve. See PARKING BRAKE CONTROL ROD under ADJUSTMENTS . Adjust parking brake after removing and installing actuator. See PARKING BRAKE under ADJUSTMENTS . If any parking brake system fluid lines are disconnected, bleed parking brake system.

System Bleeding

1. Place transmission in Park to set control valve in Park mode. Start engine. Turn steering wheel from stop to stop to bleed power steering system. Place transmission in Neutral.
2. Open bleed screw on actuator until fluid flow is free of air, then close bleed screw (bleed screw is near fluid hose connection, on top of actuator). Loosen exhaust line fitting (port EC) at control valve. (Scheme 1) Place transmission in Park. Allow small amount of fluid to bleed from fitting, then tighten fitting.
3. Cycle the system. If noisy, repeat bleeding procedure. Check power steering fluid level with transmission in Neutral and parking brake applied manually. Fluid level should be 7.12" (180.9 mm) from top of reservoir.

FRONT BRAKE CALIPER

Note. For front disc pad removal and installation, perform FRONT BRAKE CALIPER removal and installation procedures but do not disconnect brake hose from caliper (hang caliper out of way with wire). Replace all pads on an axle if wear indicator on any pad contacts rotor or if pad is worn to within 1/32" (.8 mm) of pad backing.

Removal (Floating Caliper)

1. Remove two-thirds of brake fluid from master cylinder. Raise and support vehicle. Remove wheel. Using "C" clamp or large pliers, compress caliper piston until it bottoms in its bore.
2. Disconnect brake hose from caliper. Remove caliper guide pins. (Scheme 14) Remove caliper. Remove pads from caliper. Note retainer spring on inner pad (some models) and remove if replacing pads. MD11Installation
3. Remove caliper sleeves from caliper. (Scheme 14) Apply silicone grease to outer diameter of caliper sleeves and inner diameter of bushings. Insert caliper sleeves into bushings.
4. Install retainer spring on inner pad (if removed). Install pads in caliper. Install caliper. Install guide pins and tighten to specification. See «TORQUE SPECIFICATIONS»(/gmc/jimmy-typhoon/1992-1993/remont/mechanical-hydraulic/#disc-brake-system-drum-brake-system) table at end of article.
5. Connect brake hose to caliper and tighten hose bolt to 32 ft. lbs. (43 N.m). Bleed brake system. See MANUAL BLEEDING, PRESSURE BLEEDING or VACUUM BLEEDING under «BLEEDING BRAKE SYSTEM»(/gmc/jimmy-typhoon/1992-1993/remont/mechanical-hydraulic/#disc-brake-system-drum-brake-system__bleeding-brake-system).
6. If outer pads are equipped with locking ears, bend ears toward caliper until ears touch caliper. This prevents movement of outer pad in caliper. (Scheme 9) Install wheel.

Scheme 9

Removal (Sliding Caliper)

1. Remove two-thirds of brake fluid from master cylinder. Raise and support vehicle. Remove wheel. Using "C" clamp or large pliers, compress caliper piston until it bottoms in its bore.
2. Disconnect brake hose from caliper. Remove caliper support key bolt. (Scheme 15) Using hammer and brass punch, drive out caliper support key and spring. Remove caliper. Remove inner and outer pads.

Installation

1. Using wire brush, clean corrosion from machined ways on caliper and caliper mount. Apply silicone grease to these surfaces. Install inner pad and anti-rattle spring on caliper mount. (Scheme 15) Install outer pad in caliper. Place caliper on caliper mount.
2. Using a hammer and brass punch, install caliper support key and spring. Install caliper support key bolt, ensuring bolt boss fits into circular cutout on caliper support key. Tighten bolt to 15 ft. lbs. (20 N.m).
3. Connect brake hose to caliper and tighten hose bolt to specification. See «TORQUE SPECIFICATIONS»(/gmc/jimmy-typhoon/1992-1993/remont/mechanical-hydraulic/#disc-brake-system-drum-brake-system) table at end of article. Bleed brake system. See MANUAL BLEEDING, PRESSURE BLEEDING or VACUUM BLEEDING under «BLEEDING BRAKE SYSTEM»(/gmc/jimmy-typhoon/1992-1993/remont/mechanical-hydraulic/#disc-brake-system-drum-brake-system__bleeding-brake-system). Install wheel.

Removal (All 2WD Vehicles Except Lumina APV, Silhouette & Trans Sport)

Remove brake caliper (DO NOT disconnect brake hose). See FRONT BRAKE CALIPER under REMOVAL & INSTALLATION . Remove grease cap from end of hub. Remove cotter pin, nut, washer and outer bearing. Remove rotor and hub assembly.

1. Clean and pack wheel bearings. Install rotor and hub assembly. Install outer bearing, washer and nut. Tighten nut to 12 ft. lbs. (16 N.m) while rotating rotor and hub assembly. This seats bearings.
2. Back off nut until it just begins to loosen. Finger-tighten nut. Back off nut until hole in spindle aligns with hole in nut (DO NOT back off more than 1/2 of a flat). Install new cotter pin, bend ends over and ensure ends will not contact grease cap when installed. To complete installation, reverse removal procedure.

Removal & Installation (AWD Astro & Safari, Bravada, Lumina APV, Silhouette, Trans Sport & All 4WD Vehicles)

Remove brake caliper (DO NOT disconnect brake hose). See FRONT BRAKE CALIPER under REMOVAL & INSTALLATION . Remove rotor. To install, reverse removal procedure.

Removal & Installation (4WD & AWD Except Astro & Safari, Bravada, Lumina)

For front rotor removal and installation for 4WD applicaitons and listed AWD applicaitons, see WHEEL HUB & BEARINGS under REMOVAL & INSTALLATION in FRONT SUSPENSION article.

REAR BRAKE CALIPER

Note. For rear disc pad removal and installation, perform REAR BRAKE CALIPER removal and installation procedures but DO NOT disconnect brake hose from caliper (hang caliper out of way with wire). Replace all pads on an axle if wear indicator on any pad contacts rotor or if pad is worn to within 1/32" (.8 mm) of pad backing.

Removal

1. Remove two-thirds of brake fluid from master cylinder. Raise and support vehicle. Remove wheel. Using "C" clamp or large pliers, compress caliper piston until it bottoms in its bore.
2. Disconnect brake hose from caliper. Remove caliper support key bolt. (Scheme 15) Using hammer and brass punch, drive out caliper support key and spring. Remove caliper. Remove inner and outer pads.

1. Using wire brush, clean corrosion from machined ways on caliper and caliper mount. Apply silicone grease to these surfaces. Install inner pad and anti-rattle spring on caliper mount. Install outer pad in caliper. Install caliper.
2. Using hammer and brass punch, install caliper support key and spring. Install caliper support key bolt, ensuring bolt boss fits into circular cutout on caliper support key. Tighten bolt to 15 ft. lbs. (20 N.m).
3. Connect brake hose to caliper and tighten hose bolt to specification. See «TORQUE SPECIFICATIONS»(/gmc/jimmy-typhoon/1992-1993/remont/mechanical-hydraulic/#disc-brake-system-drum-brake-system) table at end of article. Bleed brake system. See MANUAL BLEEDING, PRESSURE BLEEDING or VACUUM BLEEDING under «BLEEDING BRAKE SYSTEM»(/gmc/jimmy-typhoon/1992-1993/remont/mechanical-hydraulic/#disc-brake-system-drum-brake-system__bleeding-brake-system) . Install wheel.

Removal (9 3/4" & 10 1/2" Full-Floating Axle)

1. Raise and support vehicle. Remove brake caliper (DO NOT disconnect brake hose). See REAR BRAKE CALIPER under «REMOVAL & INSTALLATION»(/gmc/jimmy-typhoon/1992-1993/remont/mechanical-hydraulic/#disc-brake-system-drum-brake-system__removal-installation) . Remove bolts from end of axle shaft.
2. Lightly tap axle shaft flange with soft hammer to loosen shaft. Grip rib on axle shaft flange with locking pliers. Twist axle shaft to start shaft removal. Pull axle shaft from axle housing.
3. Bend lock washer tab away from lock nut. Using Wheel Bearing Nut Wrench (J-2222-C), remove lock nut. Remove lock washer. Remove adjusting nut and washer. Remove hub and rotor assembly.

1. Install hub and rotor assembly. Install washer and adjusting nut. Using Wheel Bearing Nut Wrench (J-2222-C), tighten adjusting nut to 50 ft. lbs. (68 N.m) while turning hub and rotor assembly.
2. Back off adjusting nut and tighten to 30-40 ft. lbs. (41-54 N.m) while turning hub and rotor assembly. Back off adjusting nut 135-150 degrees. Install lock washer and lock nut finger tight. Bend lock washer tab over adjusting nut flat at a minimum angle of 30 degrees.
3. Tighten lock nut to 65 ft. lbs. (88 N.m) minimum. Bend lock washer tab over lock nut flat at a minimum angle of 60 degrees. To install remaining components, reverse removal procedure.

Removal (12" Full-Floating Axle)

1. Raise and support vehicle. Remove brake caliper (DO NOT disconnect brake hose). See REAR BRAKE CALIPER under «REMOVAL & INSTALLATION»(/gmc/jimmy-typhoon/1992-1993/remont/mechanical-hydraulic/#disc-brake-system-drum-brake-system__removal-installation). Remove hub cap and gasket from hub. (Scheme 10) Install Adapter (J-2619-01) in tapped hole on axle shaft flange.
2. Using slide hammer and adapter, remove axle shaft. Bend lock washer tab away from lock nut. Using Wheel Bearing Nut Wrench(J-25510), remove lock nut. Remove lock washer, adjusting nut and washer. Remove hub and rotor assembly.

1. Install hub and rotor assembly. Install washer and adjusting nut. (Scheme 10) Using Wheel Bearing Nut Wrench (J-25510), tighten adjusting nut to 50 ft. lbs. (68 N.m) while turning hub and rotor assembly. Back off adjusting nut 1/8 turn.
2. Install lock washer and lock nut finger tight. Bend lock washer tab over adjusting nut flat. Tighten lock nut to 250 ft. lbs. (339 N.m). Bend lock washer long tab over lock nut flat. To install remaining components, reverse removal procedure.

Exploded View Of Rear Axle Shaft, Hub & Rotor Assembly (12" Full-Floating Axle). Scheme 10

Removal & Installation (Semi-Floating Axle)

Ensure parking brake is released. Raise and support rear of vehicle. Remove wheel. Remove brake drum (if necessary, back off adjuster wheel before removing brake drum). To install, reverse removal procedure. Adjust rear brake shoes. See REAR BRAKE SHOES under ADJUSTMENTS .

Scheme 11

1. Ensure parking brake is released. Raise and support rear of vehicle. Remove wheel. Remove bolts from end of axle shaft. (Scheme 11) (Scheme 11): Exploded View Of Rear Axle Shaft, Hub & Brake Drum Assembly (Full-Floating Axle)
2. Lightly tap axle shaft flange with soft hammer to loosen shaft. Grip rib on axle shaft flange with locking pliers. Twist axle shaft to start shaft removal. Pull axle shaft from axle housing.
3. Remove retaining ring and key. Using Wheel Bearing Nut Wrench (J-2222-C), remove adjusting nut. Remove washer. Remove hub and brake drum assembly (if necessary, back off adjuster wheel before removing brake drum).

1. Apply light coat of bearing lubricant to axle tube. Install hub and brake drum assembly. Install washer and adjusting nut. Using Wheel Bearing Nut Wrench (J-2222-C), tighten adjusting nut 50 ft. lbs. (68 N.m), while turning hub and rotor assembly.
2. Back off adjusting nut until just loose, then tighten until nut's inboard face contacts outer bearing cone shoulder (torque on nut MUST be zero or finger-tight).
3. Insert key into adjusting nut slot. If slot is in alignment with axle spindle keyway, loosen nut slightly but not more than one slot to align key. Install retaining ring. Install axle shaft and wheel. Lower vehicle.

REAR BRAKE SHOES

Note. For rear brake shoe removal/installation (Scheme 16)-18. DO NOT interchange left & right adjusting screw assemblies as one side is right-hand thread & other is left-hand thread.

Removal & Installation

Remove rear brake shoes. See REAR BRAKE SHOES under REMOVAL & INSTALLATION . Disconnect brake line from wheel cylinder. Remove brake cylinder retaining bolts and brake cylinder. To install, reverse removal procedure. Bleed brake system. See MANUAL BLEEDING, PRESSURE BLEEDING or VACUUM BLEEDING under BLEEDING BRAKE SYSTEM .

1. With engine off, press brake pedal several times to release vacuum in power brake unit. Clean dirt and grease from master cylinder brake line fittings. Disconnect brake lines from master cylinder and plug line ends.
2. On vehicles with combination valve and bracket attached to master cylinder mounting studs, remove combination valve and bracket. On vehicles without power brake unit, disconnect brake pedal push rod at brake pedal. On all vehicles, remove master cylinder retaining nuts and master cylinder.

1. Bench bleed master cylinder before installing. See MASTER CYLINDER BLEEDING under «BLEEDING BRAKE SYSTEM»(/gmc/jimmy-typhoon/1992-1993/remont/mechanical-hydraulic/#disc-brake-system-drum-brake-system__bleeding-brake-system) . Position master cylinder on mounting studs. Position combination valve and bracket on mounting studs (if applicable). Loosely install master cylinder retaining nuts. Connect brake lines to master cylinder but DO NOT tighten.
2. Tighten master cylinder retaining nuts. Tighten brake lines. Connect brake pedal push rod (if disconnected). Fill fluid reservoir. Bleed brake system. See MANUAL BLEEDING, PRESSURE BLEEDING or VACUUM BLEEDING under «BLEEDING BRAKE SYSTEM»(/gmc/jimmy-typhoon/1992-1993/remont/mechanical-hydraulic/#disc-brake-system-drum-brake-system__bleeding-brake-system) .

POWER BRAKE BOOSTER

Note. For Hydro-Boost removal and installation, see BENDIX HYDRAULIC BRAKE BOOSTER article in the BRAKES Section.

1. Remove master cylinder. See MASTER CYLINDER under «REMOVAL & INSTALLATION»(/gmc/jimmy-typhoon/1992-1993/remont/mechanical-hydraulic/#disc-brake-system-drum-brake-system__removal-installation) . Ensure no brake fluid contacts ABS control unit (if equipped) or related electrical connectors and wiring.
2. Disconnect vacuum hose from booster. Disconnect booster push rod from brake pedal. Remove booster mounting nuts from inside vehicle. Remove booster and gasket.
3. To install, reverse removal procedure. Bleed brake system if lines were disconnected from master cylinder. See MANUAL BLEEDING, PRESSURE BLEEDING or VACUUM BLEEDING under «BLEEDING BRAKE SYSTEM»(/gmc/jimmy-typhoon/1992-1993/remont/mechanical-hydraulic/#disc-brake-system-drum-brake-system__bleeding-brake-system) .

Removal & Installation ("C" & "K" Series)

1. Raise vehicle by frame, allowing rear axle to hang free. Remove bracket that covers valve. Remove nut and lever from valve shaft. (Scheme 4) Clean area around brake line fittings at valve. Disconnect brake lines from valve. Remove valve-to-frame bolts and valve.
2. To install, reverse removal procedure, ensuring rear axle is hanging free and valve is securely bolted to frame when lever is attached to valve (this ensures correct valve adjustment). Bleed brake system. See MANUAL BLEEDING, PRESSURE BLEEDING or VACUUM BLEEDING under «BLEEDING BRAKE SYSTEM»(/gmc/jimmy-typhoon/1992-1993/remont/mechanical-hydraulic/#disc-brake-system-drum-brake-system__bleeding-brake-system).

Removal & Installation ("P" Series)

1. Raise vehicle by frame, allowing rear axle to hang free. Clean area around brake line fittings at valve. (Scheme 5) Disconnect brake lines from valve. Remove nut and lever from valve shaft. Remove valve-to-frame bolts and valve.
2. To install, reverse removal procedure. If installing new valve, adjust the new valve. See HEIGHT-SENSING PROPORTIONING VALVE under «ADJUSTMENTS»(/gmc/jimmy-typhoon/1992-1993/remont/mechanical-hydraulic/#disc-brake-system-drum-brake-system). Bleed brake system. See MANUAL BLEEDING, PRESSURE BLEEDING or VACUUM BLEEDING under «BLEEDING BRAKE SYSTEM»(/gmc/jimmy-typhoon/1992-1993/remont/mechanical-hydraulic/#disc-brake-system-drum-brake-system__bleeding-brake-system).

Disconnect brake warning light electrical connector from combination valve switch. Disconnect brake lines from valve. Cap brake line ends. Remove valve mounting bolts. Remove valve.

To install, reverse removal procedure. Bleed brake system. See MANUAL BLEEDING, PRESSURE BLEEDING or VACUUM BLEEDING under BLEEDING BRAKE SYSTEM . Center the brake warning light switch piston by applying moderate to heavy force on brake pedal.

Scheme 12

1. Raise and support vehicle. Remove wheels and brake drums. Loosen differential cover plate and drain lubricant from axle. Remove cover plate.
2. Remove pinion shaft lock bolt. (Scheme 12)and (Scheme 13). Remove pinion shaft. Push axle shaft toward center of vehicle and remove "C" lock from end of axle shaft. Remove axle shaft. (Scheme 12): Locating "C" Lock & Pinion Shaft Lock Bolt (Astro, Safari & "S" & "T" Series Shown; Others Similar)
3. Pry seal from axle housing. Using Slide Hammer (J-2619-01) and Axle Bearing Puller (J-22813-01), remove bearing from axle housing.

1. Lubricate bearing with axle lubricant. Using Handle (J-8092) and Bearing Installer (J-23765), install bearing in axle housing until bearing installer bottoms against shoulder of axle housing.
2. Using Seal Installer (J-23771), install seal until even with surface of axle housing. Lubricate seal lips with axle lubricant. Install axle shaft and "C" lock. (Scheme 12)and (Scheme 13). Pull axle shaft outward to ensure "C" lock seats in side gear.
3. Install pinion shaft. Install NEW pinion shaft lock bolt. Tighten lock bolt to 25 ft. lbs. (34 N.m). Install differential cover and new gasket. Fill drive axle with axle lubricant.

Removing & Installing "C" Lock & Pinion Shaft On Locking Differential (Typical). Scheme 13

Removal (Except Astro, Safari & "S" & "T" Series)

1. Raise and support vehicle. Remove wheel and brake drum. Loosen differential cover plate and drain lubricant from axle. Remove cover plate. Remove pinion shaft lock bolt. (Scheme 12)and (Scheme 13).
2. On locking differential models, remove pinion shaft part way. Rotate differential case until pinion shaft contacts axle housing. Using screwdriver, rotate "C" lock until it aligns with thrust block. On all models, push axle shaft toward center of vehicle and remove "C" lock from end of axle shaft.
3. Remove axle shaft from axle housing. Using Seal Remover(J-23689), remove seal from axle housing. Remove bearing using Slide Hammer (J-2619-01) and Bearing Puller (J-23689) on 8 1/2" ring gear, or (J-29712) on 9 1/2" ring gear.

1. Lubricate bearing and seal lips with wheel bearing grease. Fill axle cavity between seal and axle with wheel bearing grease.
2. Using Bearing Installer (J-23690) on 8 1/2" ring gear or (J-29709) on 9 1/2" ring gear, install bearing until installer contacts axle housing. Using Seal Installer (J-21128) on 8 1/2" ring gear or (J-29713) on9 1/2" ring gear, install seal until even with axle housing.
3. Install axle shaft. Use care not to damage seal. Ensure splines on axle shaft engage with splines on side gear. To install remaining components, reverse removal procedure. Ensure "C" lock is fully seated or positioned in thrust block. (Scheme 12)and (Scheme 13).
4. Install pinion shaft. Install NEW pinion shaft lock bolt and tighten to 25 ft. lbs. (34 N.m). Install differential cover and new gasket. Fill axle with gear lubricant.

REAR AXLE HUB BEARINGS & OIL SEAL (FULL-FLOATING AXLE)

Note. Outer bearing race is seated against a retaining ring inside hub, on inboard side of race. Remove retaining ring from inside of hub before driving out race.

Removal (9 3/4" & 10 1/2" Axle With Disc Brakes)

1. Remove rear hub and rotor assembly. See REAR BRAKE ROTOR under «REMOVAL & INSTALLATION»(/gmc/jimmy-typhoon/1992-1993/remont/mechanical-hydraulic/#disc-brake-system-drum-brake-system__removal-installation) . Using a long drift and hammer, drive out inner bearing race, inner bearing and oil seal from outboard to inboard side of hub.
2. Remove retaining ring from inside of hub, inboard of outer bearing. Using Handle (J-8092) and Outer Bearing Race Remover/Installer(J-24426), drive out outer bearing race from outboard to inboard side of hub.

1. Clean and pack bearings with Wheel Bearing Lubricant (1051344). Using handle and Bearing Race Installer (J-8608), drive outer wheel bearing race into hub from inboard side of hub (ensure chamfered edge of bearing race installer is facing upward so that it does not contact bearing race).
2. Install retaining ring on inboard side of outer bearing race. Turn hub and rotor assembly inboard side down. Using Outer Bearing Race Remover/Installer (J-24426), seat outer bearing race against retaining ring.
3. Using Inner Bearing Race Remover/Installer (J-24427), drive inner bearing race into hub from inboard side of hub. Install inner bearing. Install new oil seal using Axle Shaft Seal Installer (J-24428).
4. To complete installation, reverse removal procedure. To adjust wheel bearings, follow REAR BRAKE ROTOR installation procedure under «REMOVAL & INSTALLATION»(/gmc/jimmy-typhoon/1992-1993/remont/mechanical-hydraulic/#disc-brake-system-drum-brake-system__removal-installation) .

Removal (9 3/4" & 10 1/2" Axle With Drum Brakes)

1. Remove rear hub and drum assembly. See REAR BRAKE DRUM under «REMOVAL & INSTALLATION»(/gmc/jimmy-typhoon/1992-1993/remont/mechanical-hydraulic/#disc-brake-system-drum-brake-system__removal-installation). Using a long drift and hammer, drive out inner bearing race, inner bearing and oil seal from outboard to inboard side of hub. (Scheme 11)
2. Remove retaining ring from inside of hub, inboard of outer bearing. Using Handle (J-8092) and Outer Bearing Race Remover/Installer(J-24426), drive out outer bearing race from outboard to inboard side of hub.

1. Clean and pack bearings with Wheel Bearing Lubricant (1051344). Using handle and Bearing Race Installer (J-8608), drive outer wheel bearing race into hub from inboard side of hub (ensure chamfered edge of bearing race installer is facing upward so it does not contact bearing race). (Scheme 11)
2. Install retaining ring on inboard side of outer bearing race. Turn hub and rotor assembly inboard side down. Using Outer Bearing Race Remover/Installer (J-24426), seat outer bearing race against retaining ring.
3. Using Inner Bearing Race Remover/Installer (J-24427), drive inner bearing race into hub from inboard side of hub. Install inner bearing. Install new oil seal using Axle Shaft Seal Installer (J-24428).
4. To complete installation, reverse removal procedure. To adjust wheel bearing, follow REAR BRAKE DRUM installation procedure under «REMOVAL & INSTALLATION»(/gmc/jimmy-typhoon/1992-1993/remont/mechanical-hydraulic/#disc-brake-system-drum-brake-system__removal-installation).

Removal & Installation (12" Axle)

Remove rear hub and rotor assembly. See REAR BRAKE ROTOR under REMOVAL & INSTALLATION. Note how outer bearing race is seated against retaining ring inside hub, on inboard side of race. (Scheme 10) Hub bearing removal and installation procedure is not available from manufacturer.

OVERHAUL

Note. For overhaul of brake assemblies (Scheme 14)DO NOT hone composite master cylinder bore. Honing destroys hardened surface, causing premature piston seal failure. If bore surface is rough or pitted, replace master cylinder.

Scheme 14

Exploded View Of Rear Brake Shoe Assembly (Lumina APV, Silhouette & Trans Sport). Scheme 15

Scheme 16

Exploded View Of Rear Brake Shoe Assembly ("C" & "K" Series With Leading/Trailing Brakes). Scheme 17

Exploded View Of Rear Brake Shoe Assembly (Exc. "C" & "K" Series-Leading/Trailing Brakes, Lumina APV, Silhouette & Trans Sport). Scheme 18

Scheme 19

Scheme 20

Scheme 21

Exploded View Of Composite Master Cylinder (Except Lumina APV, Silhouette & Trans Sport). Scheme 22

Exploded View Of Composite Master Cylinder (Lumina APV, Silhouette & Trans Sport). Scheme 23

TORQUE SPECIFICATIONS

TORQUE SPECIFICATIONS

DRUM BRAKE SPECIFICATIONS

DRUM BRAKE SPECIFICATIONS

DISC BRAKE SPECIFICATIONS

DISC BRAKE SPECIFICATIONS

See also:
• ANTI-LOCK BRAKE SYSTEM - REAR WHEEL
• ANTI-LOCK BRAKE SYSTEM 4-WHEEL
• WHEEL HUB & BEARINGS
• DESCRIPTION & OPERATION
• MANUAL BLEEDING
• PRESSURE BLEEDING
• VACUUM BLEEDING
• BLEEDING BRAKE SYSTEM
• ADJUSTMENTS
• REMOVAL & INSTALLATION