Thread: brake booster vacuum problem

Well I just recently got done putting the new motor in and now the car idles really rough. The map sensor jumps from 35-65 KPa. I noticed that my brakes also felt as though there was no brake booster connected to them. Anyways I found that when I caped the nipple on the supercharger that goes to the vacuum line to the brake booster, the car's idle smoothes out and map reading stabilizes around 45 Kpa. The vacuum line has no leak and the attachment lets air pass. I am thinking it has something to do with the brake booster ruining my vacuum pressure. Do I need a new one, or am I forgetting another vacuum line or something. If it needs to be replaced, is there a rebuild kit for it?

take a picture. the thing on the top of the blower should have all the lines filled. here, look at mine:



there is one that goes to the BBV, one that goes to the brake booster, and another that im not sure where it goes to, but i can check it a little later if need be.

Does there really need to be two threads on this?

..i thought i may have saw 3.

well not everyone checks each category everyday as some people are better with other subjects. This is a brake issue and an engine issue, so yes it feel lit belongs in two categories. the third bio saw was a question to 02blue. The vacuum lines are ran just like yours bio, and I followed the diagram. Like i said its the brake booster thats messing the pressure up when connected to the supercharger via vacuum hose.

The problem with posting in multiple sections is there's a lot of cross talk between the threads that makes it confusing.

And yes, plenty people browse every section.

doe any one know how to diagnose a brake booster once its off?

Originally Posted by Sabrewings

The problem with posting in multiple sections is there's a lot of cross talk between the threads that makes it confusing.

And yes, plenty people browse every section.

it cant hurt to get more input though

Well i took off the brake booster and tested it with my hand. There seems to be no pressure being held, and the back of it looks like it is not sealing as well. This car is almost worst then my fbody as far as everything breaking.

Originally Posted by FuglyGTP

I wish i had never sold my fbody and done a top swap on that *****. Sorry to hear about your brake booster.

Not to steal the thread but I didnt see much point in making a new one while we where on the subject. The brakes on my GP take ALOT more foot pressure than most cars. If I put my foot on the pedal and start the car, the pedal sinks. If i let the brake go, shut off the car, and press down, the pedal is the same way until i start pumping it of course. So with that little test out of the way, is this normal?

yeah thats what mine does.

that actually was the exact test to validate a working brake booster when i looked it up. lol... mine didnt sink and look at me now.