The vehicles we drive today have a braking system that consists of many sensitive components. One of these components is the master brake cylinder, which together with the calipers, brake discs and brake pads helps to stop your car. The master cylinder uses brake fluid and the concept of hydraulics to create enough pressure to push the calipers. Without a properly functioning master cylinder, your brakes will not work at full capacity.
Functions of a Master Brake Cylinder
The master brake cylinder works by pushing a piston through a cylinder. The piston compresses the brake fluid and generates pressure. The pedal under your foot is directly connected to this piston, so when you push it, the piston multiplies the force and applies it to the calipers.
Signs of a Bad Master Brake Cylinder Symptoms
A defective brake cylinder causes a number of problems for your ride, which manifest themselves in the form of symptoms. These symptoms alert you so that you can make an appointment with the mechanic and have your problems resolved.
1. Unusual Brake Pedal Activity
The brake pedal is directly connected to the master brake cylinder, so that you will feel the effect in your foot if the brake cylinder fails. The master brake cylinder increases the force you exert by folding it several times, so you don’t have to press the brakes hard each time to bring your car to a halt. In older cars this system did not exist, so drivers had to press the brake pedal very hard to generate enough force to activate the brake system. A failing master cylinder softens your brake pedal to the point where it feels spongy.
2. Dirty Brake Fluid
The master cylinder is filled with brake fluid, which it receives from the brake fluid reservoir in the engine compartment. The master cylinder is sealed with rubber seals which prevent the fluid from leaking. However, the rubber has a certain life span, after which it begins to break and deteriorate. The rubber fragments that break off mix with the brake fluid and contaminate it in the process. You will probably see small black deposits in your brake fluid reservoir when you open the brake fluid reservoir in the engine compartment. In addition, a broken cap will cause the fluid to leak, which will disable the functions of a master cylinder.
3. Check Engine Light Illuminates
Modern cars are a work of art. In the truest sense of the word, so many small and large components come together to guarantee you a smooth ride. The brake fluid pressure sensor is one such sensor, calculating the integrity of the pressure building up in the master cylinder. If there is any compromise in the pressure level, the sensor triggers the ECU, which lights up the check engine light in your dashboard. The first step to ensure that nothing else goes wrong is to visit the nearest certified mechanic.
Cleaning and Repairing the Master Brake Cylinder
The best way to improve the functions of a mechanical component is to clean it properly, especially if the part is contaminated. As mentioned above, the master cylinder can be contaminated by a deteriorating rubber seal. To clean it, you need an arsenal of a few essential tools.
Things you will need
Remove the Master Brake Cylinder
Removing the cylinder is the tricky part, as it is located deep in the engine compartment, so you have to dive under the car to remove it. Usually, this work is more suitable for a mechanic. And let’s face it, you are nowhere near qualified to lift the car safely. So, leave this kind of work to a mechanic. When you find a mechanic, ask him to give you the master cylinder. This way you can clean the master cylinder yourself very thoroughly.
Use Aerosol Cleaner
Aerosol cleaners are readily available in car dealerships. First, disassemble the cylinder and separate all parts. Clean the parts thoroughly with the aerosol cleaner so that no angle or crack is missed. Allow the parts to dry in the sun before reassembling them. Also, remember to fit a new rubber seal for protection.
Reinstall the Brake Cylinder
To reinstall the component, repeat the procedure you used to remove the component, or ask a mechanic to do the job for you.
There is not much to do in terms of repairs to a master brake cylinder. Usually it is the rubber seal that fails, which is normal. Since the rubber seal cannot be repaired, it must be replaced. However, if there is a problem with a leak or poor performance of the metal piston, a mechanic can help you. He will have to remove the master cylinder and look at its condition before he can form an opinion on the price he will charge you.
Master Brake Cylinder Replacement Cost
It is quite possible that the master brake cylinder deteriorates so much that it goes beyond repair. This is possibly due to a broken piston or insufficient brake fluid. It is therefore extremely important that you are careful with your brakes and it is highly advisable to check the brake fluid of your car from time to time.
When it comes to a new cylinder, prices can be high, but the cost you incur is directly proportional to the make and model of your car and the availability of the part. If the latter is unusual, you will inevitably have to pay more.
Normally a new master cylinder costs $120 – $200, but that’s not all. In reality, you have to pay the mechanic for his hard work. The cost he charges you depends on his skills. If he is a certified mechanic, he has earned the right to charge you exorbitant amounts. However, if your mechanic has limited experience, you can negotiate the price according to your wallet. However, on average, you should be charged $80 – $100 in labor costs.
Hello I’m Magnus, the owner and the writer of this website. I have been working with cars since I was 16 and I’m specialized with in-depth Automotive diagnostics. Also been driving drifting for the last 6 years. I’m here to give you answers to all your automotive questions and I hope that you enjoy our content.