GM Cadillac Deville_Fleetwood_ELD_Seville 1990-1998

Proportioning Valve

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The brake proportioning valves improve front-to-rear brake balance under severe brake application. Severe brake application transfers part of the vehicle rear weight to the front wheels. The resulting decrease in weight at the rear wheels can cause reduced braking efficiency and rear wheel lockup. The valves limit the pressure to the rear brakes to reduce the tendency for reduced brake efficiency.

REMOVAL & INSTALLATION



Without Anti-Lock brakes
1990 Vehicles
  1. Disconnect the negative battery cable.
  2.  
  3. Disconnect the brake lines from the proportioning valves. Plug the lines to prevent fluid loss.
  4.  
  5. Remove the proportioning valve and O-rings from the master cylinder.
  6.  

To install:

  1. Lubricate new O-rings and the external proportioning valve threads with clean brake fluid. Install the new O-rings on the proportioning valves.
  2.  
  3. Install the proportioning valves on the master cylinder and tighten to 24 ft. lbs. (31 Nm).
  4.  
  5. Connect the brake lines to the proportioning valves and tighten the fittings to 11 ft. lbs. (15 Nm).
  6.  
  7. Connect the negative battery cable. Bleed the brake system.
  8.  



Click image to see an enlarged view

Fig. Proportioning valve installation-1990 vehicles without anti-lock brakes

1991-93 Deville And Fleetwood
  1. Remove the master cylinder from the vehicle.
  2.  
  3. Clamp the mounting flange on the master cylinder body in a vise. Do not clamp on the master cylinder body.
  4.  
  5. Tap back the spring pins until they are clear of the master cylinder reservoir. Be careful not to damage the reservoir or master cylinder.
  6.  
  7. Remove the reservoir and the reservoir seals. Inspect the reservoir for cracks or deformities and replace as necessary.
  8.  
  9. Remove the proportioning valve caps, O-rings, and springs.
  10.  
  11. Using needle nose pliers, remove the proportioning valve pistons.
  12.  
  13. Remove the seals from the pistons. Inspect the proportioning valve pistons for corrosion and deformities and replace as necessary.
  14.  
  15. Clean all parts in clean denatured alcohol and dry with unlubricated compressed air.
  16.  

To install:

  1. Lubricate new O-rings and proportioning valve seals as well as the stems of the proportioning valve pistons with silicone grease.
  2.  
  3. Install the new seals (seal lips facing upward toward the cap) on the proportioning valve pistons.
  4.  
  5. Install the proportioning valve pistons, seals, and springs into the master cylinder body.
  6.  
  7. Install the new O-rings in the grooves in the proportioning valve caps. Install the proportioning valve caps in the master cylinder and tighten to 20 ft. lbs. (27 Nm).
  8.  
  9. Lubricate new O-rings and the master cylinder reservoir bayonets with clean brake fluid.
  10.  
  11. Install the O-rings on the master cylinder, making sure they are fully seated.
  12.  
  13. Install the reservoir onto the master cylinder by pressing straight down by hand until the pinholes are aligned.
  14.  
  15. Tap in the pins to retain the reservoir, being careful not to damage the reservoir or master cylinder.
  16.  
  17. Install the master cylinder on the vehicle and bleed the brake system.
  18.  

With Anti-Lock brakes
1990 Models

CAUTION
The hydraulic system contains brake fluid at extremely high pressure. It is mandatory that the system be depressurized before disconnecting any hoses, lines or fittings, or personal injury may result.

  1. Depressurize the hydraulic accumulator. The following procedure should be used:
  2.  
  3. With the ignition OFF , pressure switch disconnected, pump motor disconnected or the negative battery cable disconnected, pump the brake pedal a minimum of 25 times using at least 50 lbs. of pedal force each time. A definite change in pedal feel will occur when the accumulator is discharged.
  4.  
  5. When a definite increase in pedal effort is felt, stroke the pedal a few additional times to remove hydraulic pressure from the system.
  6.  
  7. Raise and safely support the vehicle.
  8.  
  9. Disconnect the brake lines from the proportioning valve. Plug the lines to prevent fluid loss.
  10.  
  11. Remove the proportioning valve.
  12.  

To install:

  1. Install the proportioning valve and connect the brake lines.
  2.  
  3. Tighten the brake line fittings to 11 ft. lbs. (15 Nm).
  4.  
  5. Lower the vehicle.
  6.  
  7. Fill the fluid reservoir and bleed the brake system.
  8.  

1991-98 Models
  1. Raise and safely support the vehicle.
  2.  
  3. Clean the proportioning valve and brake line connections to make sure the system will not be contaminated during servicing.
  4.  
  5. Disconnect the brake lines from the proportioning valve. Plug the lines to prevent fluid loss.
  6.  
  7. Remove the proportioning valve.
  8.  

To install:

  1. Install the proportioning valve and connect the brake lines. Tighten the brake line fittings to 11 ft. lbs. (15 Nm).
  2.  
  3. Lower the vehicle.
  4.  
  5. Fill the fluid reservoir and bleed the brake system.
  6.  



Click image to see an enlarged view

Fig. Proportioning valve-Deville and Fleetwood with anti-lock brakes, Eldorado and Seville with anti-lock brakes similar



Click image to see an enlarged view

Fig. Proportioner valve and brake line connections-1991-93 Deville and Fleetwood with anti-lock brakes

 
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