Checking the serviceability
1. A load-sensitive pressure control valve is embedded in the hydraulic line of each rear brake. The valve is attached to the bottom of the car and connected to the rear axle. The valve senses the load received by the rear axle by its displacement and prevents the rear brakes from locking during sudden braking.
2. To check the valve for proper operation, special equipment is required, so this work should be entrusted to a Renault service station. The valve cannot be repaired, and if it is faulty, it must be replaced.
Caution! On models equipped with ABS, before unscrewing the brake pipe couplings, disconnect the ground cable from the battery and do not reconnect it until the system has been bled. Failure to do so may result in air entering the hydraulic unit, which is very difficult to bleed (in some cases it is impossible) pump up.
Removal
1. Minimize fluid loss by placing a piece of polyethylene under the master cylinder reservoir cap.
2. Block the front wheels, then jack up the rear of the vehicle and place it on axle stands.
3. Wipe the area around the brake pipe connectors on the valve and place a rag under the connectors to catch any fluid that is released. To avoid mixing up the valve ports during installation, mark them relative to the pipes.
4. Loosen the union nuts and separate the brake pipes from the valve. Plug the ends of the pipes and the valve openings to minimize the loss of brake fluid and prevent dirt from entering the system. Wash off any spilled fluid with cold water.
5a. Loosen the mounting bolts.
5b. Then disconnect the valve linkage and remove the assembly from under the vehicle (refer to the illustrations).
Note: Do not loosen the rod clamp bolt - this will change the rod length and will require valve adjustment during installation.
Installation
1. Bring the valve assembly into working position and tighten the mounting bolts.
2. Install the brake pipes into the couplings on the valve and tighten the union nuts to the specifications shown Specifications effort.
3. Secure the valve linkage with brackets and lower the vehicle to the ground.
4. If a new valve assembly is installed, note that it is equipped with a special spacer shim designed to adjust the length of the rod. Achieve the rated rear axle load (the car rests on its wheels, the fuel tank is full and a person is sitting in the driver's seat), loosen the rod clamp bolt and allow the valve spring to set the rod length. Tighten the clamp bolt securely and remove the spacer from the rod.
5. Remove the polyethylene from under the master cylinder reservoir cap and bleed the entire brake system as described in Section Bleeding the brake hydraulic system.