So as I was on my lunch brake today i was driving and came to a stop behind some car. As they moved forward a bit I did the same but as I went to hit my brakes it felt like they were working and then went to the floor. I still had some brake power (very little) and luckly I was close to work, so I drove it back and parked it. I popped the hood and the master cylinder was still full of brake fluid. I had a friend come out and push the pedal while I listened for leaks, I checked all 4 wheels and there was nothing. It sounds like theres a leak coming from the master cylinder. like air blowing by. I am I right thinkg it's dead? if so any brand I should look to replace it with? Or A upgraded one from a V6 or something?

Maybe a bubble in the system? It can sometimes happen randomly. Had a '94 $hit-10(S-10 that is) where this just randomly happened, bleeding the brakes fixed the problem. My understanding is that when the MC goes bad, it leaks all over the truck(thats what my buddy's '84 did), and takes any paint that it touches with it. If you do replace it, don't use ANYTHING but OEM parts!!! It may sound stupid but trust me, from personal experiance, and the experence of many others here, nothing else seems to come even close to OEM quality. Using anything else just sets yourself up to fix it again.....I learned this after getting 5 'lifetime warranty' water pumps replaced...I guess NAPA water pumps lifetime is about 5K miles....<img src="/forums/images/graemlins/rolleyes.gif" alt="" /> BTW, I'm REALLY good at changing those things now <img src="/forums/images/graemlins/smile.gif" alt="" />

Bad vacuum booster perhaps?

I would say your brake booster has gone. Brake booster is the thing that sits behind the mastercyl.

It was the master cylinder and now it's all good!