The brake master cylinder contains brake fluid and is linked to the brakes through the brake pipes and hoses. When you step on the brake pedal, brake fluid runs from the master cylinder to the braking unit at each wheel, creating enough friction to slow down and/or stop the car. The brake master cylinder has internal and external seals that can wear out over time.
If the external seals have worn out, they will leak brake fluid, reducing the amount of fluid in the car and causing the brakes to be faulty. Worn external seals can also leak the fluid into the brake booster and destroy it. The brake booster is vital for the proper working of the brakes, so if brake fluid has leaked into it, replacement is essential.
If the internal seals have worn out, the brake fluid will continue to circulate inside, instead of being directed to the brakes. This weakens brake performance. The brake pedal will feel soft. When you apply the brakes, the pedal will go all the way to the floor without significantly slowing down or stopping the car.
After replacing the brake master cylinder, the mechanic should flush the old brake fluid out and replace it with new brake fluid.
Facts to Note:
A leaking brake master cylinder can sometimes result in a broken brake booster; in this case, both elements will need to be changed.
Brake systems are extremely sensitive to debris, so they need to be cleaned thoroughly before and during the replacement of a master cylinder.
The air will need to be bled out of the system before the new master cylinder is fixed.
How to Fix:
Inspect brake master cylinder for leaks.
Inspect brake booster.
Take out and change the brake master cylinder if faulty.
Change the brake fluid.
Bleed entire brake system of air.
Clean brake fluids from all the wheels.
Perform brake safety inspection.
Your mechanic should check the amount of brake fluid every time the car is serviced. If you feel a change in the way your brake pedal feels (a softer pedal), you should have a mechanic check the master cylinder and brake hoses. In most cars, the brake warning light should come on when the amount of brake fluid is lower than the manufacturer’s recommended amount.
Common symptoms indicating you may need to change the Brake Master Cylinder:
Brake warning light is on.
Brake fluid leak
Soft brake pedal (pedal goes all the way to the floor when pushed).
Importance of this service:
All services associated with correct function of your brakes are essential. In addition to safety issues, ignoring small repairs can quickly lead to more serious problems.