Master cylinder or brake booster?

[vipersilver]

I have a 1999 Grand Prix SE 3.1 with 149k on it. Runs great. On the way back home the other night I noticed smoke under my hood. I pulled into the driveway popped the hood and inspected. No coolant leaks, and the smoke or steam was coming from the rear of the engine. With research I thought it was a small oil leak onto the exhaust.

Got my dad to look at it. Turns out brake fluid was spraying out of the side of the brake booster onto the exhaust causing horrible steam. I also had seriously disabled brakes, but some stopping power.

with research we decided to replace the master cylinder. While testing/bleeding - no more fluid was spraying out of the side of the booster and instead my dad saw some coming from between the MC and the booster where it's connected. However he later figured that could be residual fluid. We patched everything up and I took it down the road. I had brakes, however some air in the system as we didn't bleed the wheels. Now I tested this for a half hour in the driveway and down the street, all seemed OK. I decided to take a 2 mile trip to take back the old MC core to the store.

While at a red light, I noticed my brake pedal gave a little and I saw steam from under the hood. On the way back I had no brakes again and was leaking fluid however by then it was too dark to work on it further.

Now I'm a college student and without that car I'm screwed. My dad says hes never heard of a booster going bad. All the troubleshooting methods regarding the booster didn't seem to point that it was bad - we read about hissing or the pedal not returning back. This led us both to believe that the booster is in fact functional. Not to mention it would be costly and looks to be very hard to take out. My dad says he has heard of master cylinder's being bad from the store, could this be?

any insight on this would be sweet.

[gmtech1]

Brake fluid squirting out of booster? There should not be any brake fluid in the booster. It sounds like it may be full of brake fluid from the leaking master cylinder and that fluid is causing problems inside the booster. If thats the case, you will need to replace the booster. Also, if you are low on fluid again, take a close look at the new master cylinder, and the rest of the system including all brake lines, flex hoses and calipers and make sure there is not another leak.

[vipersilver]

after we replaced the MC, and bench bled it. Nothing was spraying out of the booster anymore. Brakes worked for testing and a small drive. Then after a mile or two, no more brakes.

Others are telling me that the reman MC I got could be the culprit. As there is always a chance that they are bad.

I get vacuum for the booster. With engine off, pumped brakes, then holding brakes, turned engine on and felt it depress itself further to the floor - signaling that the booster works. I also hear no hissing.

>_<

[gmtech1]

Have seen several bad reman masters.
As far as the booster, what I was saying is that if the booster is full of fluid, it should be replaced, if its not, ok then.

[vipersilver]

bad news everyone

Replaced the master cylinder a second time, after the first reman MC failed within 20 minutes. This time, it felt like the brakes were holding up to speed, but when the car wasn't moving, the pedal just kept going in. Then, Brake fluid spraying out of the left side of the booster as you push the pedal. This happened originally as well; after failure?

All methods of testing show that the booster is working. However fluid isn't supposed to be spraying out the side of it, but there isn't supposed to be any fluid in it in the first place. Did the second reman MC fail yet again? or is the booster bad as well? Pedal firm when 30-40 upto speed. Idle or not moving - pedal goes in, fluid sprays from side of booster.