Failing mastercylinder?

 

Don't drive till you get that master cylinder checked out.

 

try and bleed your brakes, there could be air in the lines.

 

The problem moose is that if his brakes were perfectly fine until recently and now this bad that the air is leaking into the system which is usually the master cylinder.

 

ya good think'n abe lincoln.

 

yeah you'll definately want to get the lines/master checked out.

one thing also that we have ran into is we've seen some ABS modulators that were bad. if thats the case you'll want to find a place that rebuilds them since those are big $$$. the place we found is BBA remanufactering but i don't know anything else about the company.

 

Thanks, I have just finished replacing the master cylinder and will testdrive it sortly. I will let you know. Again Thanks!

 

Wow do you work quick lol.

 

Its better, bit still seems to pump up a little bit from time to time. Any ideas. Also changed all brake fluids and bleed it twice. Thanks!

 

Any chance an out of round rotor could cause this?

 

I would doubt a warped rotor would cause this. You may not have all the air out fully. Bleeding can take a few times to get it right or as Mike suggested the ABS control unit could be heading south on you. You didn't notice any brake fluid leaking down by the calipers did you, around the pistons themselves. Trying to make sure you piston seals aren't leaking by asking this question.

 

What was your bleeding procedure?

 

No leaks anywhere. I used a bleeding kit in the order specified right tire first. Bleed till new fluid came through clear.

 

Did you make sure to keep topping off your brake fluid in the resivor. It's possible that you may have drawn some air back in by accident.

 

Kept resivor topped at all times. No air in tube for a long time while bleeding

 

Found this on Sabbnet but it does not indicate if changing the MC fixed the problem. This is an exact description of my problem.

1999 95 SE 4 cyl, I Have a braking issue. The brakes stop the car, however sometimes the pedal will go almost all the way down to the floor board. When I pump the brakes once its fine. Usually this only happens when I'm driving on the freeway and have not been using the brakes for 10 minutes or so. When I'm on the brakes quite a bit theres no problem.

My first guess was calipers, but I'm doubtful of that now after examining the pad and rotor conditions. I'm thinking this may be a master cylinder issue, or possibly air in the brake lines. Before I take any steps I am wondering if anyone has experienced this problem.

 

Well as suggested earlier it may be your ABS module itself. My only other guess would be the vacuum assist module.

 

As of this morning the problem has returned in full. Check vacum pump it is work okay. Noticed something that may be interesting. with the car off the pedal pressure remains high. meaning the pedal travel stays up and good. I know that when you start the car it will lower, but even over night the pressure stayed up?
Thanks

 

This is normal. Means you don't have a leak in your brake booster. Did you recently have brake work done? You sure your caliper springs are on right? Did you replace MC with a new one or used? Sounds like air in the system still.

 

No new brake work in the past year. I did get a used MC. This is what produced the same results as the original. Could it still be the MC. What are the odds both are bad? Thanks

 

Possible both could be bad. Did you also use new o-rings when attaching the master cylinder to the vacuum pump.

 

Do you mean the oring between the booster and th MC? if so I used the old one

 

Yup exactly what I meant. Best to always use a new o-ring in critical spots like that. However that doesn't mean its the cause of your problem but its cheap and easy enough to change out in attempts to find the problem.

 

There is a hard plastic line that comes off the right side of the intake manifold that goes to the brake booster. make sure that is in there nice and tight. mine was a source for a pretty good sized vacuum leak. No brake issues, but once it was snug again, there was definitely a slightly better pedal feel.

 

Thanks I will try both. I spoke to a friend who said I need to check that the calipers are floating loose on their pins. He believes this would also cause the pedal to pump up?

 

Sorry I meant to imply taht they need to float loosely not the other way around.

 

Thanks to all. It turned out to be sping clip on one rotor was installed inproperly by last mechanic who did the brakes.

 

Good to hear. Sorry I didn't get back to you. Things have been very busy and hectic for me since you e-mailed me.