Get Operating Instructions Two Component Proportioning Valve Zkw-e

This type of valve is usually mounted to the frame or inner fender below the master cylinder.

Centering proportioning valve Next, have someone press the brake pedal while you are under the car, with a couple of fingers on the PV, so you can feel when the spool valve moves. Slowly open a bleeder to the front brake system, and in a little bit, you will hear a sharp "click" as the valve goes back on center.

The design of the proportioning valves allows air to become trapped around the proportioning valve return spring (see Figure 79.3). This air normally cannot be removed using conventional bleeding methods.

The proportioning valve doesn't have any way to bleed air, so you will have to bleed the front and rear brake lines in order to remove any air trapped in the valve.

When adjusting the proportioning valve, you increase or decrease preload on that spring pressing on the piston. More spring preload (screwing the knob or clicking the lever inward) allows more line pressure before the valve closes and proportioning begins.

When you experience uneven braking, such as your vehicle veering to one side while coming to a stop, it may be an indication that the proportioning valve in your brake system is not functioning properly. This can lead to challenges in controlling the vehicle and increase the danger during urgent braking situations.

Press the brake pedal three times, with even, gentle pressure, until the pedal is applied as far as it can go. That should recenter the valve and your proportioning valve reset will be complete. If the valve still does not reset, open one bleeder on the side of the valve that IS getting brake fluid.

Press the brake pedal three times, with even, gentle pressure, until the pedal is applied as far as it can go. That should recenter the valve and your proportioning valve reset will be complete. If the valve still does not reset, open one bleeder on the side of the valve that IS getting brake fluid.

Uneven Braking Performance and Vehicle Pull Problems with a brake proportioning valve might manifest through: A longer distance needed for stopping. The tendency of the vehicle to drift toward one direction when applying brakes.