GM Firebird 1982-1992 Repair Guide

Master Cylinder


Before removing the hydraulic components for repair, remove the clutch housing dust cover to verify the malfunction. Measure the movement of the slave cylinder push rod by pushing the clutch pedal to the floor; the minimum movement should be 14mm. Do not replace the cylinder if its movement exceeds the minimum.


See Figure 1

The clutch master cylinder is located in the engine compartment, on the left side of the firewall, above the steering column.

  1. Disconnect negative battery terminal from the battery.
  3. Remove hush panel from under the dash.
  5. Disconnect push rod from clutch pedal.
  7. Disconnect hydraulic line from the clutch master cylinder.

Click image to see an enlarged view

Fig. Fig. 1: Hydraulic clutch system

  1. Remove the master cylinder-to-cowl brace nuts. Remove master cylinder and overhaul (if necessary).
  3. Using a putty knife, clean the master cylinder and cowl mounting surfaces.
  5. To install, reverse the removal procedures. Torque the master cylinder-to-cowl brace nuts to 10-15 ft. lbs. (14-20 Nm). Fill master cylinder with new hydraulic fluid conforming to DOT 3 specifications. Bleed and check the hydraulic clutch system for leaks.


  1. Remove the filler cap and drain fluid from the master cylinder.
  3. Remove the reservoir and seal from the master cylinder. Pull back the dust cover and remove the snapring.
  5. Remove the push rod assembly. Using a block of wood, tap the master cylinder on it to eject the plunger assembly from the cylinder bore.
  7. Remove the seal (carefully) from the front of the plunger assembly, ensuring no damage occurs to the plunger surfaces.
  9. From the rear of the plunger assembly, remove the spring, the support, the seal and the shim.
  11. Using clean brake fluid, clean all of the parts.
  13. Inspect the cylinder bore and the plunger for ridges, pitting and/or scratches, the dust cover for wear and cracking; replace the parts if any of the conditions exist.

To assemble:
  1. Use new seals, lubricate all of the parts in clean brake fluid, fit the plunger seal to the plunger and reverse the disassembly procedures.
  3. Insert the plunger assembly, valve end leading into the cylinder bore (easing the entrance of the plunger seal).
  5. Position the push rod assembly into the cylinder bore, then install a new snapring to retain the push rod. Install dust cover onto the master cylinder. Lubricate the inside of the dust cover with Girling® Rubber Grease or equivalent.

Be careful not to use any lubricant that will deteriorate rubber dust covers or seals.