How To Tell If You Have A Bad Master Cylinder

The master cylinder is the heart of any brake system. So, how do you tell if you have a bad master cylinder or one that is starting to have problems?

The answer to this question is very simple on most recently sold cars. Why? The master cylinder is so hopped up with sensors that it actually will monitor itself. If any of the sensors are tripped, the corresponding brake problem light will appear on your dashboard. When this occurs, you need to get the car worked on immediately. If the master cylinder fails completely, your brakes will stop working. Being unable to stop is a really bad thing. If you are really unlucky and this happens, the parking brake should still work. Pull it lightly, slap on your distress lights and downshift until you can stop.

The chances of a master cylinder completely and suddenly failing are extremely remote. The warning signs will come long before then. What are they? Well, there are a host of them. The first should the simplest to notice. The brakes on your car will become very mushy. Why? The master cylinder works by putting the brake fluid under pressure. When the cylinder starts to fail, the pressure is decreased and you have to really pound on the brake pedal to get stopping action.

The second symptom is the “going soft” problem. No, this is not an adult male problem. Instead, the brake pedal will slowly start sinking when you are applying pressure on it to stop. Again, this is indicative of the pressure in the master cylinder not being maintained. No pressure means no stopping!

A third symptom is fluid on the ground where you park. There isn’t a lot of brake fluid in your system, so don’t expect a big spill. If you see a stain, however, it is time to pop the hood. In fact, you should pop the hood with any suspected master cylinder problem. The cylinder has rubber gaskets on it. Sometimes these will decay and the fluid can start leaking. The leak should be visible on the master cylinder. Generally, try looking below the brake fluid reservoir at the metal partition.

It should be noted that pressure problems do not necessarily mean you have a master cylinder going bad. Any problem with brake lines or any pressurized area of the system will also produce the above soft pedal symptoms. Regardless, a repair is going to be needed so you can either do it yourself or take the car into a mechanic.

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