We bought a 2000 Pontiac Grand Prix GT with 81,000 miles on it less than a week ago. The brakes have gone out. At first we thought the brakes were just wet and that is why the car would not stop properly, so we waited for them to dry off and tried again.
Later in the day the brakes were still out and there was fluid under the car. Is this a bad master cylinder and why would it go out? We did not run over anything ion the road or anything like that.
ProTech: If there is brake fluid on the ground, you need to find out where it is coming from. Depending on where you say the fluid on the ground is, it could be a leak from a line, hose, master cylinder, caliper, rear wheel cylinder, etc.
A master cylinder would usually show up on the drivers side just inward of the front wheel. After repairs, the system will need to have the air bled from the system.
Just wanted to add that if you have someone pump the brakes while looking under the car you should be able to see where it’s spraying out. That is, of course after you add brake fluid to the reservoir. Might also help to start the car while pumping the brakes- to make it easier. The fluid will spray out, so wear eye protection and notice exactly where it’s coming from.
I almost always replace the entire line if it’s a metal line- because patching it will only delay further problems.
It is pretty easy to check for leaking master cylinder. The master cylinder is the unit where you add brake fluid if you didn’t know. Just look at the back of it where it bolts to that large vacuum booster. If the master cylinder was leaking that booster would be wet and it would be going down onto the transmission. If that is not wet and the leak is in the front of the car, then you probably have a leaking line or hose. Spray down the area that is wet to clean it all off and then do just like ProTech said. Pressurizing the system will make the leak show up. Just don’t drive it until you find and repair the problem.
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