Cerridius

Hey everyone, after getting my car back together from my H/C swap I decided to upgrade my brakes and I did the LS1 front brake swap. They were weak of course because they needed to be bled, I tried and sucked so I took it to JustBrakes and had them bleed it, Brakes felt better.

But now it seems like they are not even there I have to push down pretty hard to get it to stop and after doing a WOT test today it seemed like i almost had no brakes.

Could it be from low vacuum? I only have 9.5-10in of vacuum at idle. I'm thinking it could be this because I drove the car in 1st gear up to 5k rpm, let off and let it decelerate (to get the most vacuum) and the brakes worked fine locked up front wheels and threw my girl and I forward.

Im not sure how to diagnose my problem so if you guys can give me steps to determine what the problem is that'd be great.

pgerst

Is the check valve OK? The connection at the booster to the hose is a one way valve that keeps vacuum in the booster when engine vacuum is too low, yours may be bad as it sounds like the brakes are working at your maximum vacuum.

Cerridius

Im not sure how to properly diagnose the check valve on the booster. I
Checked it by taking it off and blowing into and I couldn't but I could easily suck the air out.