Ok, with the car running, mash the brakes with someone else watching the booster line. Does it collapse?

No collapsing. I'll try again in warmer weather, though. I don't actually remember that the engine was hot the second time this failed, but it was warmed up the first time.

this crap is happening to me all the time too...what is weird is that i had the MC replaced at a dealership and my brakes are still ****...after they replaced it, it was good for a wile but then back to its old tricks...say im at a stop light, and im holding the brake...then the peddle slowly goes down and starts to lose grip..then the car slightly moves forward and i have to re pump the brakes again to get a tight grip...then it happens all over again...it seams tight at first but then gets real lose....i dont know it this is the same thing but i jsut thought im might add and see what happens

thanks
jason

I'd lose the pretty colored hose and replace it with the stock booster vacuum line. I was once part of the silicone hose club..

What Triple X has described isn't what happens to me. Only twice did the brake pedal go all the way to the floor before the car started slowing down. I'm going to replace the blue vacuum tube and see what happens, but isn't that a bit unsafe? I've never gotten the brakes to do this while the car was sitting still.

It sounds like a master cylinder...but not many change the vac hoses.

I took my car out for a ride while there was no one around. It was kind of like a ghost town, but every now and then a car drove by. The car now consistently does the thing by which the brakes suck, and it also once slowed down but didn't stop until I let go of the brake and pressed again. And every time the brakes went to the floor. Definite master cylinder? I can take care of this soon, and it'* become kind of urgent now because I need to drive this to some classes on Monday. The car seems to drive very well and slows down nicely, but I'm not too comfortable with this.

I have a ride ready if I can't do this in time, but the audio system in my car is far superior and will be missed if I can't correct this braking problem soon enough. I guess now I'm guaranteed to have a bad master cylinder, so I'm cool have no potential discrepancies. Though I still haven't changed out the brake booster vacuum line. I guess it may have become so weak that it now squishes every time, but this is most possibly not the case.

If it doesn't do it in the driveway in park and you are definitely not loosing any fluid I would start by troubleshooting the ABS. Have you tried it in the driveway and in gear just like you would be sitting at a stop light? My thinking is that a faulty MC would not care if the car were in park or in gear but the abs would.

I believe I can push the pedal quite a lot more easily now than before, and even so with the car freshly started and in park. I parked my car somewhere today and with the engine running had the brake pedal squish a bit. It'* fairly easy to press, but the car still slows down just fine. There were two instances in which I slowed down from 50mph and couldn't stop the car just by letting the pedal hit the floor. It needs to be serviced very shortly. I haven't yet taken off the rear drums, but they were done 1 year, 2 months ago or so, and they shouldn't be too rough, nor would they be hard to take off. I'll have a look and let you guys know. Thanks for helping so much, though! This is great.