The master cylinder is one of the most important parts of a vehicle’s braking system. Converts mechanical pressure to hydraulic pressure to engage the brake calipers on the wheels. Unfortunately, the brake master cylinder can also fail. These are some of the most common symptoms of a brake master cylinder failure that you need to know about.
Brake warning light comes on
When you step on the brake pedal, you push a rod into the brake master cylinder. This also pushes the pistons that are present in the cylinder bore. The thrust displaces the brake fluid and directs the fluid through the different brake circuits. The fluid then passes through the brake lines and to individual brake components on the wheel.
One of the first indicators of a bad brake master cylinder is the brake warning lighting on your dash. It is also one of the easiest ways to tell if you have problems with your brake system. Indicates a reduction in brake fluid pressure. Unfortunately, a faulty brake master cylinder isn’t the only reason the warning light comes on.
At the bottom of the brake fluid reservoir there is a brake fluid level sensor. It communicates with the car’s computer to tell it whether the reservoir contains the correct amount of fluid or not. The sensor can also fail. You can send wrong information to the computer. This can turn on the brake warning light.
A low brake fluid level can also illuminate the warning indicator. If you notice that you are filling your brake fluid more often than necessary, you may have a problem with the brake master cylinder. It can also mean that you have a leak somewhere in the brake circuit.
One way to isolate the problem is to fill the reservoir with brake fluid. This should make the symptom go away. If it comes back, then there is a potential problem with your brake master cylinder or there could be a leak somewhere along the brake lines.
Brake fluid leak
The master cylinder contains the brake fluid that you put in the reservoir. Use this fluid to activate the different brake systems on the individual wheels. Push the fluid so that the brake calipers or brake drums engage.
The brake master cylinder is located below the brake fluid reservoir. You should be able to check for a leak in the metering valves or fluid control valves. The first connects to the different brake circuits of your car. The latter receives and transports fluid from the reservoir to the master cylinder.
You can also try checking under the car. Look at the position of the master cylinder in relation to other parts of the car in the engine compartment. Also check the area on the ground directly below the master cylinder. See if there is any indication of a leak coming from this part of the brake system.
Spongy feel of the brake pedal
Another telltale sign of a brake master cylinder failure is a spongy response from the brake pedal. Under normal circumstances, the brake pedal should feel firm whenever you apply the brakes. This is proportional to the amount of force you apply to the brake pedal.
As mentioned, the brake pedal connects to the master cylinder via a pushrod. The master cylinder generates the correct level of hydraulic pressure to activate the brakes on the front and rear wheels. If there is a problem with the master cylinder, you may notice a very spongy response from the brake pedal.
One of the most common reasons you may have a spongy master cylinder-related brake pedal is worn rubber seals. These are important parts of the brake master cylinder that serve to keep the fluid inside the cylinder. If the rubber seals become damaged or worn, it can result in an internal leak. This can make the brake pedal feel spongy and soft.
However, there are other causes of a spongy brake pedal feel. The most common is the presence of air in the brake lines of the car. This prevents the brake fluid from flowing more efficiently. Damage to the brake lines can also give you a smooth feel on the brake pedal. Rust can degrade brake lines and cause leaks. Leaking calipers can also create a spongy feel.
Contaminated brake fluid
We mentioned that the cylinder …