I say you don't, just bleed the brakes for now [read your other thread]. That should be okay, but measure the hoses, when a friend applies the brakes, if it expands quite a bit, then the hoses need replacing.


-justin

Hojekang, The two things that I know of that will cause your symptoms are a bad master cylinder or leaking brake fluid. Both of these are serious problems, because a little leak can turn into a big leak in a big hurry. If you are certain you have no leaks, and the pedal slowly goes to the floor when you are trying to maintain pressure, like at a stop sign or red light, then bleeding your brakes will NOT solve the problem. It is almost certainly the master cylinder that needs to be replaced.

Bench bleed instructions as well as a pair of plastic hoses and fittings should come with the new/rebuilt cylinder. You do not need special tools. Just keep everything nice and clean. If you are not confident that you can do the work, take it to a mechanic. Brakes are not something to take chances with.

You have been very lucky to go two years without a catastrophic failure. The owner'* manual for my old '49 Plymouth offered some sage advice regarding brakes. "If your car won't go, there you are...but if your car won't stop, where are you?"

Good ideas all. I have the same problem, thought it might be the power booster and had it replaced (that wasnt it). Just saw a Carquest Bulletin today when researching (CQB 01-03) which suggests that if it isnt air then it might be the ABS motor pack. Their description of the problem sound just like Hojekang'* (and my) problem. You might want to check it out.

I've done the master cylinder thing about 100,000 miles ago. Its not too bad a job, just have someone who can follow instructions for the brake pumper. In this case is was my 8 year old daughter, NOT my wife. Go figure.

you mean, it is something to do with ABS?.
My ABS is gone ... Is it related to do the symptom?.

Same here, it was the master cylinder. The rubber 'plunger' that pushes the fluid went and would lose pressure while stopped. It was scarry, I would be sitting at a light and the car would slowly start creeping forward. A new master cylinder fixed it.

This was on my 79 Catalina.

Jay

Given the other posts here I'd guess that we both have a bad master cylinder. But for fun Google CQB 01-03 and check out the description of this failure mode.