GM Full Size Vans 1967-1986 Repair Guide

Master Cylinder

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REMOVAL & INSTALLATION



See Figures 1 and 2



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Fig. Fig. 1: Exploded view of the master cylinder and reservoir mounting



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Fig. Fig. 2: Exploded view of the master cylinder components

  1. Disconnect the negative battery cable.
  2.  
  3. Remove the lower steering column covers.
  4.  
  5. Remove the lower left side air conditioning duct (if necessary).
  6.  
  7. Remove the retainer clip and washer from the pushrod.
  8.  
  9. Disconnect the pushrod and remove the wave washer.
  10.  
  11. Disconnect the reservoir hose.
  12.  
  13. Disconnect the secondary cylinder hydraulic line from the master cylinder.
  14.  
  15. Remove the nuts that secure the master cylinder and remove the master cylinder.
  16.  
  17. Scrape all gasket material from the master cylinder and the cowl.
  18.  
  19. Remove the screws that secure the reservoir and remove the reservoir.
  20.  

OVERHAUL



  1. Remove the adapter and the seal from the master cylinder.
  2.  
  3. Pull the dust cover back and remove the snapring.
  4.  
  5. Shake the pushrod and the plunger out of the master cylinder and remove the following:

    The front seal
     
    The spring
     
    The support
     
    The rear seal and the shim.
     

  6.  

Clean all parts in clean brake fluid. Inspect the cylinder bore and the plunger for scratches, ridges and pitting. Inspect the dust cover for wear and cracking.

  1. Lubricate all seals with clean brake fluid.
  2.  
  3. Install the shim and a new seal with the flat against the shim.
  4.  
  5. Install the support and the spring.
  6.  
  7. Install a new seal.
  8.  
  9. Coat the cylinder boar with clean brake fluid and slide the plunger and the pushrod in.
  10.  
  11. Push the pushrod in and install the snapring.
  12.  
  13. Coat the inside of the dust cover with grease and slide it into place.
  14.  
  15. Install a new seal and the adapter, and install the master cylinder.
  16.  
  17. Installation is the reverse of the removal procedure.
  18.  

 
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