GM Grand Am/Achieva/Calais/Skylark/Somerset 1985-98

Proportioning Valves

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REMOVAL & INSTALLATION



See Figures 1 and 2

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Fig. Fig. 1: Proportioning valve location-early models



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Fig. Fig. 2: Proportioning valve location-late models


CAUTION
On ABS-equipped models, A Tech Iscan tool (or equivalent) is required to relieve the gear tension in the hydraulic modulator to allow for system service. Attempting to remove the proportioning valves from the master cylinder without relieving the gear tension can cause personal injury, and can damage the system components.

  1. If the vehicle is equipped with an ABS system, relieve the gear tension in the hydraulic modulator with the Tech I scan tool (or equivalent).
  2.  
  3. Disconnect the negative battery cable.
  4.  

On some vehicles, it may be necessary to remove the master cylinder reservoir for access to the proportioning valves.

  1. If necessary, remove the fluid reservoir from the cylinder, and unfasten the retaining roll pins.
  2.  
  3. Detach the proportioning valve cap assemblies.
  4.  
  5. Remove the O-rings and the springs. Discard the O-rings.
  6.  
  7. Using needle-nosed pliers, carefully remove the proportioning valve pistons. Be careful not to scratch or damage the piston stems.
  8.  
  9. Remove the seals from the pistons.
  10.  

To install:
  1. Thoroughly clean and dry all parts.
  2.  
  3. Lubricate the new piston seals with the silicone grease included in the repair kit or brake assembly fluid. Install to the pistons with the seal lips facing upward toward the cap assembly.
  4.  
  5. Lubricate the stem of the pistons and install to their bores.
  6.  
  7. Install the springs.
  8.  
  9. Lubricate and install the new O-rings in their grooves in the cap assemblies.
  10.  
  11. Install the caps to the master cylinder and tighten to 20 ft. lbs. (27 Nm).
  12.  
  13. If removed, install the master cylinder reservoir.
  14.  
  15. Fill the reservoir with brake fluid.
  16.  
  17. Connect the negative battery cable. and check the brakes for proper operation.
  18.  
  19. Bleed the air from the brake system as necessary. Refer to the appropriate procedure in this section.
  20.  

 
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