Symptoms of bad Brake Master Cylinder

The master brake cylinder is that part of the braking system whose primary responsibility is to convert the pressure from the brake pedal to hydraulic pressure. It does this by releasing the brake fluid into the brake circuit in a controlled manner according to the force the driver applies on the brake pedal. Both the disc and the drum brakes have the master cylinder. In this guide, we will go through some of the symptoms of a bad brake master cylinder.

Symptoms of bad Brake Master Cylinder

The master cylinder is a mechanical part of the braking system and might experience some technical hitches which might make it malfunction. In such a case, your truck will show weird symptoms. You must know such symptoms as they will enable you to tell whether your master cylinders need a mechanical check-up. 

Check Lights on the Dashboard

The brake warning lights on your dashboard are the easiest way to realize a problem with your master cylinder, but when the light shows up, it does not necessarily mean that it is the master cylinder having trouble. The brake check light will show when other parts of the braking system are faulty.

If the brake sensors detect a drop in the pressure of the brake fluid, it will show a brake check light. In this case, consider checking the condition of the master cylinder. A bad cylinder interferes with the level of the brake fluid. 

If the master cylinder leaks fluids, the ABS check light will show up. 

Leaking Brake Fluid

There is a minimum level of brake fluid that your master cylinder will need for it to create hydraulic pressure. It is the hydraulic pressure that performs the role of slowing down your truck. If your master cylinder leaks the brake fluid, the fluid’s level will have to go down, and stopping your truck becomes difficult. In such a condition, consider replacing your master cylinder. 

A Soft or Spongy Brake Pedals

You will realize that your master cylinder is having problems when you feel your brake pads are soft when you apply maximum pressure on them. The master cylinder has rubber seals. The primary role of rubber seals is to prevent brake fluid leakages. If the rubber seals are faulty, the brake fluid will leak, leading to a spongy brake pedal.

Contaminated Brake Fluid

Another sign that your master cylinder is faulty is when you note that your brake fluid has dirt particles. The dirt gets into the brake fluid when the rubber seals are faulty. The role of the rubber seals is to keep the brake fluid in its place and prevent any contaminant from coming into contact with it.

The presence of impurities in the brake fluid interferes with the generation of adequate pressure to stop your truck. You will realize that you are pressing the pedals very hard, but you still find your truck braking as usual.


The master cylinder generates the hydraulic pressure necessary to stop your truck. However, when the master cylinder is faulty, your vehicle is likely not to eliminate correctly. The brakes might fail to function or respond slowly. This guide has shown some signs that your master cylinder is faulty.

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