Stumped!!! Help please.

1986 Honda Accord. Brake light is on. I bled system, still have soft pedal. Bench bled and replaced Master cylinder. Now pedal is soft still and I hear air when I push the pedal ( don't remember hearing this before). No obvious leaks, lines are good. Hissing is coming from front right by booster. Also, this is weird, when I push the pedal the idle will go up and down. If I hold down the brake pedal it will push back up on me and rev at the same time.


Is this a bad booster/vacuum pulling from the carb that's making weird idle/soft pedal? Could this correlated? Or did I maybe pull a vacuum hose while replacing (I checked thoroughly) and that's screwing up the idle?

Please ...your advice is greatly appreciated!!!

:stupid:

u most likely have air in ur brakes which is not a good thing as u know. Check the booster hose from ur brake booster to the carb. If its loose it will hiss. its probably ur carb fucked up, it did that to me too. well if also might be that ur battery is dying and when u apply ur breaks, ur break lights draw amp and no matter how much ur altenator is putting out current, ur battery is in last stages. Also u might have a fucked up vaccum system like mine did. but got tired of all that carb crap with guess and check, time to get to efi buddy. :D

I figured it out. When I replaced the m/c I left the seal between the booster and the m/c on the old one. So I called the store, went down and got it. That probably pulled too much vacuum in affecting idle, and gave me zero brake since I had no seal. I'll have to test this theory tomorrow. But it was BETTER braking and had no idle problem before I put the new M/C on. So that's got to be it. Thanks.

which vaccum lines to teh carb control teh brakes?? i removed almost all the vaccum lines and i still have breaks!

Follow the large vacuum line from the brake booster.

It's the Big Ass vacuum line. Like the diameter of your thumb....

what happens if it is removed? cuz i think i might have removed it, but my brakes still work.

the pedal would be hard as hell to push if you removed it. Check your checkvalve for the vacuum booster.

The vacuum supplies the boost/assist. Like the prior post said it would feel like you were pushing a rock if it weren't pulling vacuum.