Proportioning valves on Isuzu vehicles are mounted in two locations: (1) On the master cylinder, inline with the rear brake lines. (2) On the frame rail below the master cylinder.
- Disconnect the negative battery cable.
- Disconnect and plug the brake lines at the master cylinder (proportioning valve).
- Remove the proportioning valve(s).
- Installation is the reverse of the removal procedure. Torque the proportioning valves attached to the master cylinder to 30 ft. lbs. Torque brake lines to 12 ft. lbs.
- Bleed the brake system.