Clutches GMC S15 Pickup

DESCRIPTION

The hydraulic clutch consists of a clutch plate, pressure plate and a release bearing. Hydraulic clutch has a master cylinder with a separate reservoir. Clutch pedal moves master cylinder push rod and a secondary cylinder at the clutch housing moves clutch fork and release bearing.

TRANSMISSION APPLICATION

BLEEDING HYDRAULIC CLUTCH SYSTEM

Note. Never use fluid which has been used or bled from the system to fill reservoir.

1. Fill reservoir with clean DOT 3 brake fluid. Disconnect slave cylinder from bellhousing, leaving line attached. Hold slave cylinder at a 45 degree angle with bleeder screw facing upward.
2. Have an assistant depress clutch pedal while opening bleeder screw. Close bleeder screw and release pedal. Repeat sequence until all air is removed from system. Ensure master cylinder reservoir stays full during bleeding process.

CHECKING HYDRAULIC CLUTCH SYSTEM

Check hoses for cracks, wear or other damage. Check hydraulic cylinders for loose mounting and signs of leakage. Clutch pedal travel should be at least 8" (203 mm). Secondary push rod travel, at clutch fork, should be at least 1" (25 mm). If necessary, bleed hydraulic system.

Removal ("C", "K", "R" & "V" Series)

1. Disconnect negative battery cable. On 2WD models, remove shift lever boot attaching screws and slide boot up shift lever. Place transmission in Neutral and remove lever.
2. On 4WD models, remove center console, shift boot, boot bridge, and selector switch. On all models, raise and support vehicle. Remove skid plate and disconnect vacuum harness.
3. On all models, remove drive shaft(s). Disconnect speedometer cable and wiring from transmission. Remove clutch slave cylinder. Support transmission and remove transmission mount bolts.
4. Remove exhaust pipes, crossmember and any other components needed for clearance. Remove dust cover bolts. Remove transmission mount bolts. Carefully remove transmission and transfer case (if equipped).

Installation

To install, reverse removal procedure. Lightly coat input shaft splines with high-temperature grease.

Removal ("M, "S" & "T" Series)

1. Disconnect negative battery cable. Remove shift lever boot. Shift transmission in Neutral. Disconnect shift control rods (if equipped). Remove shift lever.
2. Raise and support vehicle. Remove brake cable for clearance. Mark drive shaft for reassembly reference. Remove drive shaft.
3. Disconnect speedometer cable and wiring from transmission. Disconnect exhaust pipe. Support transmission. Remove support braces and skid plate (if equipped). Remove other components, as needed, for clearance.
4. Remove clutch slave cylinder from transmission. Remove crossmember. Remove bolts holding transmission to engine. Remove transmission from vehicle.

1. To install, reverse removal procedure. Lightly coat input shaft splines with high-temperature grease to aid in reassembly.
2. Shift transmission into high gear. Install support braces. Tighten braces to clutch housing before tightening to transmission. Install new seal on speedometer cable. Adjust shift linkage. Add transmission lubricant.

Removal

1. Remove transmission. Remove slave cylinder from bellhousing. Remove screws and flywheel cover. Remove bellhousing. Remove clutch fork and release bearing. Remove ball stud or clutch fork retainer if worn or damaged.
2. Install clutch pilot in clutch disc during removal. Mark flywheel and pressure plate for reassembly reference. Evenly loosen pressure plate bolts one or 2 turns at a time until clutch plate spring tension is released. Remove clutch pilot, pressure plate and clutch disc.

1. Support clutch disc and pressure plate on flywheel with clutch pilot. Ensure reference marks are aligned. Tighten bolts evenly to avoid distortion.
2. Remove pilot. Lubricate ball stud and fork fingers with high-temperature grease. Lubricate O.D. groove and pack grease into I.D. recess of release bearing.
3. If clutch fork retainer is being replaced, install retainer so that fingers and tabs fit into release bearing groove and retainer wraps around flat side of ball stud. (Scheme 1) Reverse removal procedure to complete installation.

Scheme 1

1. Disconnect negative battery cable. Remove steering column covers or panel. On "C", "K", and "S" series, remove A/C duct from lower left side of instrument panel.
2. On all models, disconnect push rod from clutch pedal. Disconnect reservoir hose at master cylinder. Remove master cylinder retaining nuts. Remove master cylinder.

To install, reverse removal procedure. Bleed system. See BLEEDING HYDRAULIC CLUTCH SYSTEM under SERVICE (IN VEHICLE) in this article.

Scheme 2

Removal & Installation

Raise and support vehicle. Disconnect and cap the hydraulic line at the slave cylinder. Remove the slave cylinder. To install, reverse removal procedure. Bleed the hydraulic system. Refer to BLEEDING HYDRAULIC CLUTCH SYSTEM under SERVICE (IN VEHICLE) in this article.

Scheme 3

Disassembly & Inspection

1. Pull back dust cover and remove snap ring from cylinder. Extract push rod. Remove plunger and spring assembly. Pull out reservoir adapter and adapter seal. (Scheme 2)
2. Remove spring from front of plunger. Remove seal support, front seal, and shim from plunger. Be careful not to damage plunger surface. Clean all parts with clean brake fluid.
3. Ensure cylinder bore is smooth. Inspect bore for visible ridges or scores. Master cylinder must be replaced if scored or damaged.

Reassembly

1. Lubricate seals and cylinder bore with clean brake fluid. Fit back seal into groove in plunger. Install front seal on plunger with flat side against shim. Install seal support and spring.
2. Carefully install plunger assembly into bore. Depress plunger with push rod and seat snap ring in groove. Lightly grease inside of dust boot and install. Put reservoir seal into master cylinder and press reservoir into place.

1. Remove push rod and dust cover. Remove snap ring. Remove plunger and spring assembly from cylinder. Remove seal from plunger. DO NOT damage plunger surface. (Scheme 3)
2. Clean all parts in clean brake fluid. Inspect cylinder bore for ridges or scratches. Bore must be smooth. Replace cylinder if damaged.

Place seal in groove on plunger. Lubricate bore and seal with clean brake fluid. Slide spring and plunger assembly into cylinder bore. Depress plunger far enough to install snap ring in groove. Lightly grease inside of dust boot and install boot. Install push rod.

ADJUSTMENTS

The hydraulic clutch system is nonadjustable.

TORQUE SPECIFICATIONS

TORQUE SPECIFICATIONS

See also:
• BLEEDING HYDRAULIC CLUTCH SYSTEM