BMW Coupes and Sedans 1970-1988 Repair Guide

Proportioning Valve

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Models equipped with anti-lock brakes require expensive and specialized equipment to bleed the brake system. If you do not own or have access to this equipment, it is best to have a properly equipped professional perform this procedure.

REMOVAL & INSTALLATION



2500, 2800, Bavaria, 3000 and 3.0 Models

When removing or installing brake line or hoses, always use a backup wrench on the fitting to prevent twisting. Avoid bending the lines or damaging the coating.

  1. Remove as much brake fluid from the reservoir as possible.
  2.  
  3. Unscrew the left rear brake hose at the control arm and brake pressure regulator. Unscrew the brake lines at the pressure regulator limiter.
  4.  
  5. Remove the regulator mounting bolts at the underside of the body and remove the regulator.
  6.  
  7. Install the regulator and reconnect the lines. Fill the reservoir with clean brake fluid and bleed the system.
  8.  

318i, 325, 325e, 325i, 325iS, 325iX and M3 Models

Models equipped with anti-lock brakes require expensive and specialized equipment to bleed the brake system. If you do not own or have access to this equipment, it is best to have a properly equipped professional perform this procedure.

  1. Draw off hydraulic fluid from the master cylinder.
  2.  
  3. Disconnect the brake lines at the top and bottom of the proportioning valve. place a container under the lines to catch any brake fluid which may drip out.
  4.  
  5. Remove the clamp from the valve and unfasten the pressure connection at the union.
  6.  

To install:
  1. Check the day/year codes, reduction factor, and switch-over pressure on the replacement valve is identical.
  2.  
  3. Install the valve and reconnect the brake lines.
  4.  
  5. Fill the reservoir and bleed the brake system.
  6.  

320i Models

When removing or installing brake line or hoses, always use a backup wrench on the fitting to prevent twisting. Avoid bending the lines or damaging the coating.

  1. Remove as much brake fluid as possible from the reservoir.
  2.  
  3. Tag for identification, then disconnect the four brake lines at the proportioning valve.
  4.  
  5. Unscrew the two mounting bolts from the inner front left wheel well and remove the valve.
  6.  

To install:
  1. If replacing the valve, replace with a valve bearing the code 25 and an 18mm piston diameter.
  2.  
  3. Install the valve to the fender wall using the mounting bolts.
  4.  
  5. Connect the brake lines. Fill the reservoir with clean brake fluid and bleed the system.
  6.  

 
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