GM: Electra/Park Avenue/Ninety-Eight 1990-1993

Master Cylinder

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Fig. Fig. 1 Removal or installation of master cylinder-1990 vehicles



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Fig. Fig. 2 Removal or installation of master cylinder-1991-93 vehicles



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Fig. Fig. 3 Exploded view of the 1990 diagonally split master cylinder

For 1990 vehicles equipped with abs, see the proper anti-lock brake section for replacing the Hydraulic Assembly (Teves ii high pressure system).

REMOVAL & INSTALLATION



  1. Disconnect the negative battery cable and, if equipped, the electrical connector from the level sensor unit.
  2.  

If equipped with Teves ii Anti-lock Brake System (abs), ensure that the hydraulic accumulator is fully depressurized before disconnecting any hydraulic lines, hoses or fittings. Read the Teves ii abs information first for safety.

  1. Using the proper flare nut wrench, disconnect and plug hydraulic lines from the master cylinder.
  2.  
  3. Remove the mounting bolts and the master cylinder assembly.
  4.  

To install:

  1. Install the master cylinder assembly and mounting bolts.
  2.  
  3. Connect the hydraulic lines to the master cylinder.
  4.  
  5. Connect the negative battery cable and, if equipped, the electrical connector to the level sensor unit.
  6.  
  7. Refill the master cylinder with new dot 3 brake fluid. Bleed the brake system.
  8.  

OVERHAUL



1990 Without ABS
  1. Do not remove the plastic reservoir unless there is damage to the reservoir or seals.
  2.  
  3. Remove the fluid sensor switch with the proper tool.
  4.  
  5. Remove the proportioner valve cap assembly, O-ring, spring, piston and seal.
  6.  
  7. Push the primary piston in and remove the snapring.
  8.  
  9. Apply low pressure compressed air to the upper outlet port at the blind end of the bore with all other ports plugged in order to remove the primary piston assembly, secondary piston, spring and spring retainer.
  10.  
  11. Inspect all parts for chipping, excessive wear or damage. When using a master cylinder repair kit, install all the parts supplied.
  12.  
  13. Be sure all recesses, openings and internal passages are open and clean. Check all rubber parts that can be reused for rips, swelling and other damage.
  14.  
  15. Inspect the master cylinder bore for signs of pitting, scoring or rust.
  16.  

Do not hone aluminum master cylinders. There is a special coating on the aluminum which will be removed if honed. This will damage the master cylinder and will cause it to fail.

To assemble:

  1. When assembling, dip all parts except the master cylinder body in clean brake fluid.
  2.  
  3. Assemble the secondary piston assembly with new seals.
  4.  
  5. Install the secondary piston assembly and spring into the master cylinder.
  6.  
  7. Install the primary piston assembly into the master cylinder.
  8.  
  9. Install the snapring.
  10.  
  11. Install the proportioner valve assemblies with new O-rings.
  12.  
  13. Install the fluid level switch.
  14.  
  15. Install the reservoir, if removed, with new seals and install the cap(s).
  16.  
  17. If equipped with a fluid level switch, remove the plug and remove the switch assembly. If any corrosion is present in the bore, the master cylinder must be replaced. Otherwise, remove the O-rings and retainers from the piston. Install new O-rings and retainers and install the piston in it's bore. Install the Allen® head plug with a new O-ring.
  18.  

 
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