GM S10/S15/Sonoma Pick-Ups 1982-1993 Repair Manual

Master Cylinder and Reservoir

Print

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

REMOVAL & INSTALLATION



See Figure 1

  1. Disconnect the negative battery cable.
  2.  
  3. Remove hush panel or lower filler panel from under the dash.
  4.  
  5. If necessary, remove the lower left A/C duct.
  6.  
  7. Remove the push rod retainer, then disconnect push rod from clutch pedal.
  8.  
  9. Either disconnect the reservoir hose (if the reservoir is not being removed or if there is no clearance for reservoir removal with the hose installed) or remove the reservoir retainers.
  10.  



Click image to see an enlarged view

Fig. Fig. 1: Exploded view of a common master cylinder and reservoir assembly mounting

  1. Disconnect slave cylinder hydraulic line from the clutch master cylinder. Immediately plug all openings to prevent system contamination or excessive fluid loss.
  2.  
  3. Remove the master cylinder-to-cowl brace nuts. Remove master cylinder and overhaul (if necessary).
  4.  

To install:
  1. Using a putty knife, carefully clean all old gasket material from the master cylinder and cowl mounting surfaces.
  2.  
  3. Install the master cylinder to the cowl using a new gasket. Tighten the retainers to 13 ft. lbs. (18 Nm).
  4.  
  5. Remove the caps, then connect the slave cylinder hydraulic line to the master cylinder assembly.
  6.  
  7. Either connect the reservoir hose or install the reservoir and secure using the retainers.
  8.  
  9. Connect the push rod to the pedal and secure using the retainer.
  10.  
  11. If removed, install the lower left A/C duct.
  12.  
  13. Install the hush/filler panel.
  14.  
  15. Connect the negative battery cable.
  16.  
  17. Properly refill the master cylinder reservoir, then bleed the system of air and check for fluid leaks.
  18.  

OVERHAUL



See Figure 2

Most vehicles covered by this manual utilize an easily rebuilt clutch master cylinder assembly. The below procedure may be used for most hydraulic clutch master cylinders. Of course, the price of a replacement should be compared to the price of a rebuild kit and the time involved to service the old component.

  1. Remove the filler cap and drain fluid from the master cylinder.
  2.  
  3. Remove the reservoir adapter and seal from the master cylinder.
  4.  
  5. On the end of the assembly, pull back the dust cover and remove the snapring.
  6.  
  7. Remove the push rod assembly. Shake the push rod and plunger out of the cylinder body. If difficulty is encountered, gently tap the master cylinder assembly on a block of wood to help eject the plunger assembly from the cylinder bore.
  8.  
  9. Remove the seal (carefully) from the front of the plunger assembly, ensuring no damage occurs to the plunger surfaces.
  10.  
  11. From the rear of the plunger assembly, remove the spring, the support, the seal and the shim.
  12.  



Click image to see an enlarged view

Fig. Fig. 2: Exploded view of the clutch master cylinder assembly

  1. Using clean brake fluid, clean all of the parts.
  2.  
  3. 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.
  4.  

To assemble:
  1. Use new seals, lubricate all of the parts in clean brake fluid (DOT 3), fit the plunger seal to the plunger and reverse the removal procedures.
  2.  
  3. Insert the plunger assembly, valve end leading into the cylinder bore (easing the entrance of the plunger seal).
  4.  
  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.
  6.  

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

 
label.common.footer.alt.autozoneLogo