My car ('99.0 2.8L Q Tip) has been sitting since February, because I've been laid up with a broken ankle. When I parked it the brakes worked ok, not great, but the car stopped. They did feel weakish; at the time I thought it just needed new pads. Fast forward three months and now the car is basically un-drivable. There is no braking power and you have to really stomp on it to stop even at slow speeds.

There is a normal amount of pedal travel, and it seems firm, not spongy, but the car doesn't stop. There is a scraping noise coming from all four corners, but I think that's just rust residue on the rotors from sitting so long. Just driving around the block helped clean them up some. I checked the pads and they still have plenty of wear left in them. The rotors also show no abnormal wear. I had bought a set of pads and rotors to replace them, but I don't think thats what my problem is.

Only thing I can think of at this point is air or contaminates got into the fluid. In that case, bleeding at all four corners would help or solve my problem, correct? Only other thing I can think of is I have a bad master cylinder, but I would think that would have been more gradual. Basically, the car went from stopping fine to un-drivable just from sitting for a few months.

Any ideas? Thanks.

 

Come on people, this is the internetz. Everyone has an opinion. Just looking for ideas, not a slam dunk diagnosis. I know I've given a generic description but there are only a few things it could be. I just want to narrow it down.

 

check all pipes for signs of leakage , and around cylinder, and pistons, somethings gone somewhere , or a collapsed rubber pipe .......

how much fluids in the chamber?????/

you could do with getting all four wheels off some one to pump brakes whilst you check around.


thats your starting job before replacing things

 

Forgot to mention that, fluid reservoir is full, fluid looks/smells normal. No noticeable leaks anywhere.

 

then id be firstly trying a full system bleed with fresh fluid going through it , and failing that could be a seal in master cylinder

give it a good bleeding first

 

maybe a break line/ hose is failing to a few of ur pistons. that doesn't necessarily mean there is a leak. but besides that, you definitely need to bleed all of those suckers. don't press too hard on the brake pedal when you bleed them. you might cause more damage to the lines. might as well get those new rotors and pads in there while ur at it.

 

Definitely flush and fill, and as mentioned above, a bad brake cylinder diaphragm can cause this - it's not necessarily gradual either since the car has been sitting. Could also be seized calipers although all four seizing seems remote.

 

Alright, thanks everyone. I'll report back after I do the flush. Hopefully this does trick.

 

Ok, I completely flushed the brake fluid at all four corners. As it came out at each corner it was brown at first then greenish before the new stuff came through. Took it out for a drive and it stopped better but still not normal. Still seems like too much pedal travel, and just not enough grab. I didn't do the pads/rotors yet, and the rotors on the car have a good layer of rust. After driving and braking hard the rotors cleared up for the most part, but the car still isn't stopping the way it should.

I'm going to try flushing the fluid again, and putting the new pads and rotors on.

 

Problem solved.

Turned out to be a combination of bad brake fluid, glazed pads, and rusted rotors. I just replaced the front pads and rotors today and the car stops 100 times better. I still need to do the backs, but first I need to pick up a compressor tool for the rear calipers.

Thanks for the help everybody.