Brake Proportioning/Combination Valve: Service and Repair

Removal Procedure

Important: Prior to replacement of the combination valve, note the identification code on the valve. It is necessary to have the proper code when replacing the valve.





1. Remove the combination valve electrical connector (10).
2. Remove the front and rear brake pipes.
3. Remove three alien bolts (11) securing combination valve (12) to the Brake Pressure Modulator Valve (BPMV) (4).
4. Remove the combination valve from the BPMV.

Important: Do not reuse the transfer tubes (13). Always install new transfer tubes with a new combination valve.

Important: Verify that the replacement combination valve has the same pin punched identification code as the code found on the old part.

5. Remove two transfer tubes (13).

Installation Procedure





1. Install two new transfer tubes (13) into the combination valve (12) until fully seated.
2. Install combination valve (12) to BPMV (4).

Notice: Refer to Fastener Notice in Service Precautions.

3. Install three combination valve Allen bolts (11).
Tighten bolts first to 8 Nm (6 ft. lbs.), then to 16 Nm (12 ft. lbs.).
4. Front and rear brake pipes to combination valve.
Tighten brake pipe fittings to 17 Nm (13 ft. lbs.).
5. Connect combination valve electrical connector (10).

Important: Verify that the combination valve metering rod is depressed during bleeding.

6. Bleed the brake system.