What is the purpose of a metering valve in brakes?

What is the purpose of a metering valve in brakes?

For your disc / drum brake system, a metering valve is essential for proper balance. A metering valve will control fluid flow from the master cylinder causing the rear drum brakes to engage just before the front disc brakes. This allows the car to settle evenly under braking instead of nose diving.

What is the difference between a proportioning valve and a metering valve?

The metering valve works with a front disc/rear drum setup to hold off pressure to the front brakes until pressure has been applied to the rear brakes. The proportion valve works in a panic situation to hold off rear brake pressure and prevent rear brake lock-up.

Does the metering valve delays front brake action?

The metering valve delays the flow of brake fluid to the front calipers until the pressure in the system rises to a point where the wheel cylinder can overcome the tension of the brake shoe return springs. This prevents the front brakesfrom locking up during light brake applications.

How do you unblock a brake proportioning valve?

Bleed the front brake lines on the proportioning valve in the same fashion. This reversal of pressure will eventually break the spool loose inside the proportioning valve, equalizing the pressure between the front and rear brakes. The dash light will go off.

What are the symptoms of a bad metering valve?

Metering Valve Cause: 1 – Valve stuck OPEN: If the valve is stuck open, the vehicle will have instant-on front brakes (See figure 48.1). The front brakes will apply instantly, while the rear brakes will have to “play catch up.” The long-term symptom of instant-on front brakes is premature front pad wear on all pads.

How do I know if my metering valve is bad?

Since the proportioning valve decreases the pressure sent to the rear brakes, the main symptom the valve is going bad is the rear wheels locking up when the brakes are applied. Furthermore, the wheels will lock up more easily on wet surfaces. The rear brakes may feel touchy when applied even gently.

Do drum brakes need a proportioning valve?

A Proportioning valve is required on vehicles that have disc brakes on the front wheels and drum brakes on the rear wheels. Disc brake pads are normally in contact with the disc, while the drum brake shoes are normally not in contact with the drum.

Is a brake proportioning valve necessary?

Yes. The addition of a proportioning valve is a must. Without it your braking system will not operate properly.

Does the proportioning valve controls pressure to the front brakes?

The proportioning valve reduces the pressure to the rear brakes. Whichever type of brakes your vehicle has, the rear brakes require less pressure than the front brakes. If equal braking force were applied to all four wheels during a stop, the rear wheels would lock-up before the front wheels.

How do I know if my proportioning valve is bad?

First, you might notice your car is taking a nose dive when you suddenly apply the brakes. Then your car may not stop fast enough. If your rear wheels lock up easily, especially when you drive on wet surfaces, it is a good sign your proportioning valve is going bad.