Three Signs That Your Brake Booster Valve Is Not Working (And How To Replace It)

Your car’s braking system contains a vacuum brake booster that is responsible for creating pressure. You may notice several symptoms if your brake booster valve is defective.

It is important to ensure that the brake pedal works properly every time you use it. To help you out, we will look at the problems a defective brake booster check valve can cause and discuss what’s required to fix it. Let’s take a quick look at the signs to look for first.

A stiff pedal is the most obvious sign of a bad brake booster valve. There may be other symptoms such as trouble braking, or check engine lights on your dashboard.

Here’s a more detailed list of the most common symptoms of a bad brake booster check valve:

Three Bad Vacuum Brake Booster Valve Symptoms

1. Hard Brake pedal

Stepping on the pedal shouldn’t be difficult when everything is working as it should. The brake booster valve could have a problem if you press down on the pedal, making it difficult to push.

The brake booster's vacuum pressure will be reduced if the check valve is worn down. As the brake pedal becomes more firm, it will require greater pressure to press down. Because the check valve is defective, which is supposed to regulate pressure in the mastercylinder, this causes it to become more firm. 

2. Trouble Making

A small leak in the check valve for the vacuum brake booster may cause the booster to not work properly. This will result in less effective brakes and require more force to stop.

It is time to inspect your brake booster valve if your vehicle's stopping distance seems longer than normal.

A bad brake booster can cause brake pedal problems.

3. Check engine light

To create vacuum within the brake booster system, the check valve for brake booster uses vacuum pressure generated by the air intake. It is measured using the MAF sensor. If the valve leaks, it can result in loss of measured oxygen. This could cause the car's engine to go lean, or rich.

If your car runs too low or high in fuel, you will see a warning light and stored code. To locate any air-fuel mixture problems codes, you can use the OBD2 scanner.

Brake Booster Valve Check Location

The brake booster usually has the brake booster check valve. If you don’t see it there, it would be found in line with the vacuum hose. 

The vacuum booster is a dome-shaped component that’s mounted near the rear wall of the engine compartment. You should be able to find it on the driver’s side of the vehicle, running in line with your brake pedal. The vacuum hose runs from the intake manifold to the booster. 

The Function of a Vacuum Brake Booster Valves

There are several parts of the brake booster. However, the most crucial component is still its check valve. When the engine is running, it creates vacuum pressure by drawing vacuum from the intake and leaving the brake booster.

While the check valve may be a minor part, it's essential to ensure the correct link between vacuum hoses and the brake booster. Reliable check valves ensure the brakes function properly every time you press the stop button. 

The life expectancy of the brake booster check valve is approximately the same as the vehicle's lifetime. In fact, it doesn’t get inspected during a routine brake check and there is no maintenance to perform. With that said, the lack of attention means that when it breaks or fails, it isn’t noticed until symptoms occur. 

Brake booster check valve replacement cost

It costs between $70-$85 to replace the brake booster check valve. The labor cost for a brake booster check valve replacement will generally be between $30 and $40, while parts should run around $40. 

If you have some mechanical knowledge, replacing the brake booster check valve isn’t a complicated process. With the correct tools, you can do this yourself and save some money. To access the check valve, you will need to take out a couple clamps as well as the vacuum hose. 

But, it is possible that other services will need to be done simultaneously. If air gets into the lines due to the defect, brakes need to be cleaned.