scubanut Posted November 9, 2011 Report Share Posted November 9, 2011 Just started to happen last week. The brake pedal is real soft, and will slowly go down to the floor at a stop. If i pump it a second time, they are hard and stay that way! Thinking the booster is bad, but not sure. Haven't done any brake work in 10K miles, and ran real good all summer long. was going to put it away this week, snow in the forcast! Link to comment Share on other sites More sharing options...
vbrad511 Posted November 9, 2011 Report Share Posted November 9, 2011 You've got some air in the system. First place to look is where the master bolts to the booster. Bet you've got a trail of fluid leaking down. Link to comment Share on other sites More sharing options...
scubanut Posted November 9, 2011 Author Report Share Posted November 9, 2011 If thats the case, (I'll check this afternoon) then the master cylinder is junk then right? Link to comment Share on other sites More sharing options...
miamipops Posted November 9, 2011 Report Share Posted November 9, 2011 I am having the exact problem. Parked it in the garage to see if I can detect the leak when it hits the floor. No luck. The master is from Rock Auto. Will check again. Link to comment Share on other sites More sharing options...
Indiana Posted November 9, 2011 Report Share Posted November 9, 2011 (edited) If you did a rear ABS delete it will take a quart of fluid bled out the rear calipers to get all the air out but a spongy pedal from having air in the system isn't the same as one that continues to slowly go down. If you didn't flush out the rusty fluid it can get back into a new master and if its really dirty it will bypass the seal and the pedal slowly drop to the floor and you'll have no brakes. Maybe tomorrow it will drop to the floor and do nothing and you crash. You need to first bench bleed your new master because its empty and it won't suck fluid in when it can just push air back and forth. Open the lines, push the pedal down, cover the holes up where the lines went (you have to do both because there's two chambers inside) then let the pedal up and that will draw fluid in. Repeat a few times and mash the pedal slowly or when the air is out fluid will blast in your face. You can do that before you mount it or after one is more messy in the car than the other. Edited November 9, 2011 by Indiana Link to comment Share on other sites More sharing options...
scubanut Posted November 10, 2011 Author Report Share Posted November 10, 2011 Can't find any leaks anywhere! I'll deal with it in spring, have enough stuff to rebuild/replace this winter! Link to comment Share on other sites More sharing options...
Indiana Posted November 11, 2011 Report Share Posted November 11, 2011 (edited) It doesn't leak. When the fluid is rusty that means there's some rust on the seal and some pits in the cylinder wall usually and when you push the pedal you expect NO fluid at all to leak past that seal otherwise you couldn't call this part of a braking system. This is what is happening and you can't see it. Edited November 11, 2011 by Indiana Link to comment Share on other sites More sharing options...
scubanut Posted November 11, 2011 Author Report Share Posted November 11, 2011 Thanks, that will be my number one priority in spring. The brake fluid is really crappy looking, I'm gonna get some new braided brake hoses all around, a new master cylinder and flush the entire system. Its all original yet, this was my dads car he bought new in 87 and was really neglected the last ten years he had it. Just turned 81K original tho. Link to comment Share on other sites More sharing options...
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