Brake Proportioning/Combination Valve: Service and Repair

Proportioning valves should never be disassembled.

1. Raise and support vehicle, then disconnect and remove battery cables.
2. Remove battery heat shield, hold-down clamp and battery from tray, then lift access cover off tray.
3. Remove speed control vacuum reservoir from battery tray without disconnecting vacuum lines, then remove battery tray from vehicle.

Fig 53 Proportioning Valve Replacement:

4. Remove battery acid shield from modulator assembly, then remove brake tube from proportioning valve.
5. Remove proportioning valve from modulator assembly.
6. Reverse procedure to install, noting the following:
a. Prior to installing proportioning valve, moisten sealing O-ring with clean brake fluid.
b. Torque proportioning valve to 26 ft. lbs. and brake tube nut to 13 ft. lbs.