How To Unstick A Brake Proportioning Valve: An Easy Guide

When you are driving, safety should always be prioritized. The brake proportioning valve is one of the first defense lines in any vehicle, ensuring control while on the road.

However, this valve can become stuck or malfunction over time, affecting the balance of braking power. It’s a common problem but can pose significant risks.

Luckily, I have some easy tips to get your brakes flowing smoothly again in no time.

Keep reading to learn more about how to unstick a brake proportioning valve and get back on the road with confidence!

What Is A Brake Proportioning Valve? 

how to unstick a brake proportioning valve

Brake proportioning valves play an essential role in the braking system. Their main job is to distribute the braking force between the front and rear wheels.

When you press the brake pedal, the car’s weight shifts forward, putting more pressure on the front wheels.

The proportioning valve regulates the hydraulic pressure going to the brakes based on the weight distribution of the vehicle.

It limits the amount of pressure sent to the rear drum brakes, allowing them to brake slightly less forcefully than the front brakes.

Thanks to this part, the vehicle’s stability and control are maintained. Like every mechanical system, though, the valve can wear out and get stuck at any time.

Depending on the specific situation, a stuck proportioning brake valve may cause some problems: 

  • Uneven braking: The proportioning valve may get stuck in a position that restricts or reduces the hydraulic pressure going to the front or rear brakes.
  • This can result in uneven braking force distribution, causing the vehicle to pull to one side during braking. It may lead to longer stopping distances and compromised control.
  • Rear wheel lock-up: Suppose the proportioning valve gets stuck in a position that limits the hydraulic pressure to the front brakes but allows the excessive pressure to the rear brakes.

It can force the rear wheels to lock up prematurely during braking. This can lead to skidding, loss of control, and potentially dangerous situations.

  • Front wheel lock-up: In some cases, a stuck proportioning valve may restrict brake pressure to the rear brakes while allowing excess pressure to the front brakes.

This can cause the front wheels to lock up before the rear wheels, resulting in a loss of steering control and increased stopping distances.

All of the scenarios above pose significant risks, and it is better to be safe than sorry.

You should perform a thorough check on your car as soon as you see signs of brake proportioning valve problems.

How To Unstick A Brake Proportioning Valve: A Step-By-Step Guide

brake proportioning valve location

The proportioning valve often gets stuck due to debris and corrosion. In most cases, you can unstick the brake proportioning valve by cleaning and lubricating the valve.

If this doesn’t solve the problem, a standard brake bleed procedure is required.

Read on and let me guide you through each step: 

Step 1: Safety First

Before attempting any repairs or maintenance on your vehicle, it is crucial to prioritize safety. Park your vehicle on a level surface, engage the parking brake, and chock the wheels to prevent any movement.

Wear appropriate safety gear, such as gloves and safety glasses, throughout the process.

After parking the car, open the hood and fill the master cylinder with the right type of brake fluid for your car.

Step 2: Inspect The Brake System 

Press the pedal and check the brake light on the dashboard to see if it is flashing.

If you didn’t have to repair a leak from the cylinders or calipers recently, the brake proportioning valve might have stuck, causing the brake light to turn on.

In case your brake system has leaked before, you’ll need to conduct a brake bleed procedure.

Step 3: Locate The Proportioning Valve

The next step in how to unstick a proportioning valve is to locate this component. It is typically mounted on the brake lines near the master cylinder or the rear axle.

Consult your vehicle’s auto repair manual to identify the specific brake proportioning valve location in your car.

Step 4: Clean And Lubricate The Valve

Visually inspect the valve for any signs of damage or leakage. Ensure the valve is free from debris, rust, or any other obstructions.

Use a clean cloth or a small brush to gently wipe away any dirt or grime accumulated on the valve.

Stuck valves are often the result of rust or corrosion. Apply a suitable lubricant, such as penetrating oil, to the valve’s moving parts.

Allow the lubricant to penetrate for a few minutes to loosen any stuck components.

Step 5: Bleed The Brake Fluid 

If the step above doesn’t release the valve, a brake bleed procedure is required. Get someone to be in the driving seat and put a container to collect the fluid beneath the right rear wheel.

Use a piping wrench to loosen the brake bleeder screw. Instruct the other person to press the brake pedal several times and maintain pressure on it.

Let the brake fluid flow out by loosening the brake bleeder screw. Repeat if there are air bubbles until clear fluid comes out.

Step 6: Work The Valve

Using the right tool, like pliers or a wrench, carefully turn the valve’s adjustment bolt counterclockwise to release any tension.

Be cautious not to force the valve, as excessive pressure can damage it further.

Give the brake proportioning valve light taps with a small hammer to loosen any rust or dirt.

After that, find the brake lines that go to the back brakes and the lines that go to the front brake calipers.

Step 7: Check Front And Rear Brake Lines

Use a flare piping wrench on the rear brake line’s cap nut. Have your assistant press the brake while you get the cap nut opened.

If the pedal doesn’t move down, instruct your assistant to apply pressure on the brake pedal. If the valve gives off a “click” sound and the brake light goes out, close the valve.

The spool inside the valve has centered.

In case the brake light still flashes, use a piping wrench to loosen a cap nut on the front brake while your assistant keeps the pedal pressed down.

Loosen the nut and wait until fluid comes out. When the light turns off, your assistant should let you know.

If the light remains on, instruct your assistant to apply more pressure on the brake pedal while you listen for a click. Once done, close the cap nut.

Repeat the same process on the rear brake line.

Step 8: Test the Brake System

After bleeding the brake fluid, the pressure between the two brakes should be equalized, and the light will be turned off.

Once you have successfully unstick the proportioning valve, testing the brake system before driving the vehicle is crucial.

Pump the brakes several times to build pressure and ensure that the brakes engage smoothly and evenly.

If you notice any irregularities or inconsistencies, such as the brake feeling spongy after bleeding, consult a professional mechanic for further inspection and repair.


reset proportioning valve

What Are Some Common Ford Brake Proportioning Problems?

Common brake proportioning problems in Ford vehicles include stuck proportioning valves, leaking proportioning valves, and malfunctioning brake light switches.

Can You Reset The Proportioning Valve Chevy?

Yes, you can. To reset proportioning valve on a Chevy, find the valve on the rear brake line. You will see a “reset” button. Hold this button for 5 seconds, and the valve will be reset.

However, keep in mind that resetting proportioning valve won’t solve the root of the problem if your Chevy has a stuck valve.

What Will Happen If You Remove The Brake Proportioning Valve?

Removing the brake proportioning valve will result in an unregulated distribution of brake pressure between the front and rear wheels.

This can lead to imbalanced braking, rear wheel lock-up, longer stopping distances, handling issues, reduced braking performance, and even brake failure.

It is not recommended to remove the proportioning valve unless for specific modifications, as it can significantly impact the safe operation of the braking system.


The brake proportional valve plays a vital role in ensuring the safe operation of a vehicle’s brake system.

If the valve becomes stuck or malfunctions, it can compromise the balance of braking power and affect overall safety.

By following the step-by-step guide on how to unstick a brake proportioning valve, you can deal with this problem on your own.

However, if you are unsure or encounter difficulties during the process, it is recommended to seek professional assistance.

Remember, safety should always be your top priority when working on any part of your vehicle’s braking system.

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