Need brake help
 

Have 2001 SE, brakes bleed off, when you step on them they start with a good peddle but bleed all the way to the floor. With the engine running if you keep pumping the fluid will start going down but when you stop pumping the fluid will come back up in the master cylinder. If you turn the engine off, after you work off the vacuum to the booster you will have a full solid peddle. :confused:

Air in the brake lines. Could also be water in the lines, but I'm going to bet air. Air compresses a lot, which is why you're getting the petal to the floor. Could also be a bad leak, but you'd have fluid on the ground under the car at some point, and would be filling the master cylinder often.


You're misusing the term bleed when describing the problem. You need to bleed the brakes to get the air out of the system. It could be really complicated since you likely have air in the master cylinder from being too low on fluid at some point. If this is something you have never done, take it to a place like firestone, let them troubleshoot it for you. They can determine if it's just bad fluid and/or air in the line, and bleed it for you, or if it's a mechanical problem requiring new parts. Get there yesterday, driving with bad brakes is taking a huge risk!

It has not been run low on fluid. There has not been anything done to the brakes in about a year so I don't think it would be any air in the lines. Was driving it when the brakes started to act up. When I stopped to check it the master cylinder was full. But when you shut the engine off and you work off the vacuum off the power brakes then you have a full peddle. Then start it back up and press the peddle you have a full peddle but then it creeps down to the floor and if you keep pumping it up and holding the peddle til it goes back to the floor the fluid starts to go down in the master cylinder when you stop pumping the peddle then the fluid comes back up in the master cylinder. Sounds crazy I've never seen anything like that in my 60 years of working on vehicles.

It has to be air in the system. If it's not, perhaps a blown seal inside the master cylinder, either way, discussing it in theory isn't getting you fixed safely.

My guess is that it is the master cylinder leaking internally.

But since this problem is a difficult one to diagnose, the main point to get across is to take the car to a qualified repair place and have them diagnose it. This is a situation where it doesn't matter why this happened or who did what to whom. As previously stated, it is dangerous to be driving that car, so don't delay.

Thanks guys for the help

I'm replacing the booster and master cylinder I'll see if that is the problem

I am having the same problems,check my thread in 5th gen. if the pedal is hard with the car off and softer with the car on the booster is fine.

The booster and master cylinder fixed it. I think the master cylinder was the problem. Again thanks for the help. Now the ABS light is on hopefully I can reset it.

I think on our cars the ABS resets once the car moves for x mph. But I had difficulty finding the proper OBD2 reader for our ABS (my other cars no problem a program on the laptop read all codes)--ordered one that cost $150 and was supposed to work, but did not. Ended up simply driving with no ABS...(didn't want to randomly replace wheel speed sensors etc)

Good to hear!

Right. If it slowly sinks to the floor after you start it, then it could be an internal master cylinder leak. It's supposed to drop a little bit when you start it but not keep going down .