REMOVAL & INSTALLATION
Bendix ABX-4 System
See Figure 1
You do not have to remove the HCU when replacing the proportioning valves.
- Disconnect the negative battery cable.
- Disconnect the brake line fitting from the faulty proportioning valve in the HCU.
- Unscrew and remove the proportioning valve requiring replaced from the HCU.
- Lubricate the O-ring seal on the new proportioning valve with clean brake fluid, from a fresh sealed container.
- Install the proportioning valve in the HCU and hand-tighten it until it is fully installed and the O-ring seal is seated in the HCU. Then, tighten the valve to 30 ft. lbs. (40 Nm).
- Connect the brake line to the proportioning valve and tighten the line nut to 12.5 ft. lbs. (17 Nm).
- Bleed the base brake system in the usual fashion.
Teves Mark 20 System
See Figure 2
Never attempt to disassemble a proportioning valve.
- Raise and safely support the vehicle.
- Remove the chassis brake tube nuts from the proportioning valve controlling the rear wheel of the vehicle which has premature wheel skid.
- Remove the proportioning valve from the chassis brake tube.
- Install the proportioning valve in the chassis brake tube.
- Tighten the 2 chassis brake tube nuts to 12.5 ft. lbs. (17 Nm).
- Bleed the affected brake line, as outlined in this section.