GM Celebrity/Century/Ciera/6000 1982-1996 Repair Guide

Clutch Master and Slave Cylinder


The clutch hydraulic system is removed and serviced as a complete assembly.

The clutch driven disc may contain asbestos, which has been determined to be a cancer causing agent. Never clean clutch surfaces with compressed air! Avoid inhaling any dust from any clutch surface! When cleaning clutch surfaces, use a commercially available brake cleaning fluid.


See Figure 1

  1. Disconnect the negative battery cable.
  3. Remove the hush panel from inside the vehicle.
  5. Remove the clutch master cylinder retaining nuts at the front of the dash.
  7. Remove the slave cylinder retaining nuts at the transaxle.
  9. Remove the hydraulic system as a unit from the vehicle.

To install:
  1. Install the slave cylinder to the transaxle support bracket aligning the pushrod into the pocket on the clutch fork outer lever. Tighten the retaining nuts evenly to prevent damage to the slave cylinder. Tighten the nuts to 40 ft. lbs. (54 Nm).

Do not remove the plastic pushrod retainer from the slave cylinder. The straps will break on the first clutch pedal application.

  1. Position the clutch master cylinder to the front of the dash. Tighten the nuts evenly to 20 ft. lbs. (27 Nm).

Click image to see an enlarged view

Fig. Fig. 1: Clutch hydraulic system

  1. Remove the pedal restrictor from the pushrod. Lube the pushrod bushing on the clutch pedal. Connect the pushrod to the clutch pedal and install the retaining clip.
  3. If equipped with cruise control, check the switch adjustment at the clutch pedal bracket.

When adjusting the cruise control switch, do not exert an upward force on the clutch pedal pad of more than 20 lbs. or damage to the master cylinder pushrod retaining ring may result.

  1. Install the hush panel.
  3. Press the clutch pedal down several times. This will break the plastic retaining straps on the slave cylinder pushrod. Do not remove the plastic button on the end of the pushrod.
  5. Connect the negative battery cable.


This is a tedious, time consuming job. You can save yourself a lot of trouble by buying a rebuilt master cylinder from your dealer or parts supply house. The small difference in price between a rebuilding kit and a rebuilt part usually makes it more economical, in terms of time and work, to buy the rebuilt part.

  1. Remove the master cylinder.
  3. Remove the reservoir cover and drain the fluid.
  5. Remove the pushrod and the rubber boot on non-power models.
  7. Unbolt the proportioners and the failure warning switch from the side of the master cylinder body. Discard the O-rings found under the proportioners. Use new ones on installation. There may or may not be an O-ring under the original equipment failure warning switch. If there is, discard it. In either case, use a new O-ring upon assembly.
  9. Clamp the master cylinder body in a vise, taking care not to crush it. Depress the primary piston with a wooden dowel and remove the lock ring with a pair of snapring pliers.
  11. The primary and secondary pistons can be removed by applying compressed air into one of the outlets at the end of the cylinder and plugging the other three outlets. The primary piston must be replaced as an assembly if the seals are bad. The secondary piston seals are replaceable. Install these new seals with the lips facing outwards.
  13. Inspect the bore for corrosion. If any corrosion is evident, the master cylinder body must be replaced. Do not attempt to polish the bore with crocus cloth, sandpaper or anything else. The body is aluminum, polishing the bore won't work.
  15. To remove the failure warning switch piston assembly, remove the Allen head plug from the end of the bore and withdraw the assembly with a pair of needlenose pliers. The switch piston assembly seals are replaceable.
  17. The reservoir can be removed from the master cylinder if necessary. Clamp the body in a vise by its mounting flange. Use a pry bar to remove the reservoir. If the reservoir is removed, remove the reservoir grommets and discard them. The quick take-up valves under the grommets are accessible after the retaining snaprings are removed. Use snapring pliers, no other tool will work.
  19. Clean all parts in denatured alcohol and allow to air dry. Do not use anything else to clean and do not wipe dry with a rag, which will leaves bits of lint behind. Inspect all parts for corrosion or wear. Generally, it is best to replace all rubber parts whenever the master cylinder is disassembled and replace any metal part which shows any sign of wear or corrosion.
  21. Lubricate all parts with fresh brake fluid before assembly.
  23. Install the quick take-up valves into the master cylinder body and secure with the snaprings. Make sure the snaprings are properly seated in their grooves. Lubricate the new reservoir grommets with fresh brake fluid and press them into the master cylinder.
  25. Install the reservoir into the grommets by placing the reservoir on its lid and pressing the master cylinder body down onto it with a rocking motion.
  27. Lubricate the switch piston assembly. Install new O-rings and retainers on the piston. Install the piston assembly into the master cylinder and secure with the plug, using a new O-ring on the plug. Tighten to 40-140 inch lbs. (5-16 Nm).
  29. Assemble the new secondary piston seals onto the piston. Lubricate the parts, then install the spring, spring retainer and secondary piston into the cylinder. Install the primary piston, depress and install the lock ring.
  31. Install new O-rings on the proportioners and the failure warning switch. Install the proportioners and tighten to 18-30 ft. lbs. (25-40 Nm). Install the failure warning switch and tighten to 15-50 inch lbs. (2-6 Nm).
  33. Clamp the master cylinder body upright into a vise by one of the mounting flanges. Fill the reservoir with fresh fluid. Pump the piston with a dowel until fluid squirts from the outlet ports. Continue pumping until the expelled fluid is free of air bubbles.
  35. Install the master cylinder and bleed the clutch. Check the clutch system for proper operation.


Bleeding air from the system is necessary any time part of the system has been disconnected, or the fluid level in the reservoir has been allowed to fall so low that air has been drawn into the master cylinder.

Never under any circumstance use fluid that has been bled from the system as it could be contaminated with air or moisture.

  1. Clean the cap then remove the cap and diaphragm and fill the reservoir to the top with certified DOT 3 brake fluid.
  3. Fully loosen the bleed screw which is in the slave cylinder body next to the inlet connection. Fluid will now begin to move from the master cylinder down the tube to the slave. It is important that for efficient gravity fill, the reservoir must be filled at all times.
  5. At this point bubbles will be noticeable at the bleed screw outlet showing air is being expelled. When the slave is full, a steady stream of fluid will come from the slave outlet. At this point, tighten the bleed screw to 18 inch lbs. (2 Nm).
  7. Install the diaphragm and cap to the reservoir. The fluid in the reservoir should be level with the step.
  9. The hydraulic system should now be fully bled and should release the clutch. Check the vehicle by starting, then push the clutch pedal to the floor and selecting reverse gear. There should be no grinding of gears, if there is, the hydraulic system still contains air. If so, bleed the system again.