I've done 4 seperate searches with tons of results each, but none have answered my question directly...so here I am.

I just did a rear brake swap and got everything put back together last night. After bleeding the system four times, I still get no pedal pressure on the brakes when the car is running. When the car is off, I can pump them and regain pressure, so I assume the booster is ok, which makes me think it's the MC (tell me if my logic is wrong here).

However, after the third round of bleeding, I noticed a pretty significant leak on the front right between the hardline and the caliper line. I tightened up the connection and bled the system one more time. Still no pressure. I would have done it another 10 times if I could but I ran out of brake fluid after stores were closed.

My question is, is this complete loss of pressure with the car running indicative of a bad MC? If the seals were bad wouldn't I also lose pressure with the car turned off? I never dropped the pedal to the floor while bleeding, although I may have done only a couple times accidentally with the car on while testing the system after bleeding. Would a little air in the lines from the previous leak cause a complete loss of pressure like that? I thuoght it would just be a little spongy, but I guess it depends on how much is left in there? I actually lost sleep over this last night and just need some advice. Thanks in advance to anyone who can offer some.

 

Sounds more to me like a bad booster. When a booster is dying you have to pump it for the brakes to work. MC will usually stop the car then slowly sink to the floor if it has leak.

 

Booster was fine before the swap, no problems whatsoever. What would cause it to go back all of a sudden? As for pumping the brakes, regardless of how much I pump them with the car running I still get no pressure. Do you still think it could be the booster? Wouldn't a bad booster mean that I would have a harder time pushing in the pedal with the car running?

 

Does your pedal sink to the floor when the car is running and also when the car is off if you DONT pump them? I was having a similar problem where I could pump them when the car was off and get pressure so I also thought my brake booster but then I went and just pressed the pedal and held it there to see if the pedal would still sink when the car was off which it did so I replaced my M/C and everything was fine after that.

 

im having a similar problem. i lose pedal pressure if i don't pump them up i actually had the pedal to the floor to stop the car and it wouldn't stop! i ended up using my e-brake to stop to get home...SCARY... anyways i was thinking the MC was out because the booster is what allows you to pump them up....right?.....

i ordered a MC today and i plan on installing it later this afternoon. i'll let you all know how it works out.

 

i would say you MC has gone bad

 

yeah, I just got a new MC and i'll be installing it later tonight. thankfully autozone had one in stock.

 

keep us posted....i wanna know how this one turns out....

 

Just a follow up one how my weekend went. Turns out the hardline connectino points on the Autozone MC were too small in diameter to fit my hardlines. So after twenty minutes of attempting to screw the ******* things in and spilling brake fluid on the whole left side of my engine bay I said **** it and put the old MC back on. Just for **** and giggles my friend and I decided to bench bleed to old and and try things one more time with it. While bleeding the brakes my friend noticed that the Speed Bleeders actually weren't working anymore. Fluid was being pushed out of the caliper and then being sucked right back in. So the whole time I was "bleeding" my brakes by myself for those couple days I was basically filling my whole system with little tiny air bubbles....damn speed bleeders. A friend came over and helped me bleed the right way and everything is working fine. Anyone else had problems with speed bleeders before?