Your car’s brake system is made up of many components that work in harmony to stop the vehicle when you step on the pedal. If one part fails, the entire system is compromised. It couldn’t be more obvious than when you come across a faulty vacuum brake booster.
We look at the main symptoms of a bad vacuum brake booster and discuss what it does. We also evaluate the cost of replacing a vacuum brake booster and determine if it is safe to drive when this part fails. Let’s start first with a quick look at the signs:
The most common symptom of a faulty brake booster is a stiff brake pedal associated with increased braking distance. Sometimes you may also hear a whistling sound coming from the engine when it is idling. A warning light may also appear on the dashboard.
Here is a more detailed list of the most common symptoms of a bad brake booster:
Bad Vacuum Brake Booster Symptoms
1. Hard brake pedal
When you try to brake your car, you shouldn’t have to apply much pressure. This is true except when the vacuum brake booster deteriorates.
When this essential component fails, you lose brake assist. To stop the vehicle, you will have to press the brake pedal very hard.
2. Longer braking distance
Most drivers have a good idea of how long it takes to stop the vehicle. If that time seems to drag on, something is wrong.
When the brake assist function is lost, you have to apply much more power to stop the car. This increased braking distance can occur suddenly or subtly, depending on how quickly the part fails.
Brakes can make a variety of noises, from screeching to grinding, none of which are good. However, the distinctive whistling noise belongs to a faulty vacuum brake booster.
When the vacuum brake booster begins to leak, air escapes from the diaphragm or housing. This air push results in a hiss that is most prominent when the brakes are applied.
4. Dashboard warning lights
Your modern vehicle is equipped with a multitude of sensors that alert you when a problem arises. The anti-lock braking system is no different.
If you get an ABS warning on your dashboard, it could be a sign that something is wrong with the vacuum brake booster. Not only will your braking ability be affected, but you could also have problems with the traction and stability control systems, which have their own warning lights.
No-load brake booster function
The brake booster helps the driver when braking a vehicle. Greatly reduces the effort required when applying force to the master cylinder. The master cylinder is responsible for distributing the fluid to the brakes for their correct operation.
There are three models of brake booster, the most popular being the vacuum brake booster. However, some vehicles include hydraulic boost or an electronic assembly model instead.
In the vacuum brake booster, the internal diaphragm separates the two different sides. These compartments are called the working chamber and the vacuum chamber. As the brakes are released, you will find the same amount of vacuum on both sides. However, when you press the brake pedal, a control valve allows more pressure to enter the working chamber. The result of this is the activation of a pushrod that applies force to the master cylinder, allowing brake assist to assist the driver’s efforts.
Location of vacuum brake booster
The vacuum brake booster is located between the firewall and the brake master cylinder. To replace the booster, you will also need to remove the master cylinder. This is why many people choose to replace both parts at the same time.
The brake booster check valve is located directly on the brake booster. If there is not, it may be in the vacuum hose. However, some of these check valves are built directly into the suction pipe and therefore cannot be repaired. If the check valve was damaged, you may need to replace the entire vacuum hose assembly.
Vacuum Brake Booster Replacement Cost
The average vacuum brake booster replacement cost is between $300 and $700, depending on the car model and labor costs. Labor will cost between $100 and $200, while parts typically cost more than $150.
However, several factors affect how much you’ll pay, including the type of vehicle you drive, how difficult it is to reach the brake booster, and what other parts need to be replaced.
Most vacuum brake boosters will last 150,000 miles or more and rarely fail. However, vehicles operating in dry climates may experience more dry rot, which can cause the vacuum brake booster diaphragm to deteriorate prematurely and lead to failure.
If the vacuum brake booster fails, you should not continue driving your vehicle. In fact, you should never drive with even the slightest indication that something is wrong with your brake system. If your brakes are more difficult to operate and you are having trouble stopping your vehicle, it is time to have the system inspected by a qualified mechanic.