Load Sensing Proportioning Valve

* Due to the need for special equipment to accurately check and adjust brake fluid pressure after installing (or connecting) the valve, it is recommended that this work be performed by qualified specialists. The removal and installation procedures for the valve are described in case it is absolutely necessary to perform this work. However, after the valve is installed, contact a specialist to accurately check and adjust the brake fluid pressure.

* If brake fluid pressure is not checked and correctly adjusted, braking effectiveness may be significantly reduced.

Removal

PROCEDURE
1. Position the vehicle over a service pit or raise it on a hoist. The vehicle may also be placed on ramps, but it must be kept level on its wheels.
2. To reduce brake fluid loss, remove the master cylinder reservoir cap and place a polyethylene film over the reservoir opening. Secure the film with a rubber band so that air cannot enter under the film.
3. Loosen the brake line fittings where they connect to the load sensing proportioning valve. To avoid rounding the fitting flats, use a flare nut wrench when loosening them.
4. Disconnect the brake lines from the valve and cap their ends to prevent dirt or moisture from entering.
5. Loosen the lock nut and adjusting nut, and remove the spring bracket from the crossmember.
6. Remove the three bolts and remove the valve together with its mounting bracket.

Installation

PROCEDURE
1. Install the valve and tighten the three bolts.

2. Install the spring bracket and temporarily tighten the lock nut below the adjusting nut. Turn the adjusting nut and lock nut to set the initial spring length A to approximately 4-1/8 in. (101.6 - 3.175 mm). Tighten the lock nut while holding the adjusting nut.
3. Connect the brake lines and bleed the brake system (refer to Subsection 9.12).
4. Lower the vehicle to the ground and have a specialist check and adjust the brake fluid pressure.