87 supra brake booster problem

[Rob1]

ok one day while driving my brakes began to feel a bit soft but would firm up again when pumped, now when car is running the brake petal is very soft and brakes are not very responsive and if i pump the brake hard a few time my engine begind smoking! i figured i had a leak spraying onto exhaustbut i looked closly and the smoke is all coming from my exhaust leak between manifold and cat, and also pouring out of the tail pipe. i pump breaks hard it smokes for a few min then stops untill i pump break again, i disconected vacumm line from booster and pluged the line going to engine to avoid vacumm leak and the problem stopped. any ideas??? thanks

[cre]

Loosing brake fluid? Check the hose going from the booster to the intake manifold for oil inside it.

It's time to tear down the master cylinder and inspect it for bad seals and deterioration.

http://www.cygnusx1.net/Supra/Librar...Section=BR&P=9
http://www.cygnusx1.net/Supra/Librar...spx?F=4702&P=1

You're going to need to clean out the booster as well once you repair/replace the master cylinder:

http://www.cygnusx1.net/Supra/Librar...ection=BR&P=20
http://www.cygnusx1.net/Supra/Librar...spx?F=4703&P=1

Make sure the check valve to the booster isn't sticking due to the contaminants in the vacuum line:

http://www.cygnusx1.net/Supra/Librar...spx?F=4703&P=2 (Make sure you put the check valve back on in the same orientation it was in originally!)

Fix the exhaust leak.

[Rob1]

Thanks alot that was some really good info. ill look into it i also found a guy selling a master cylinder and booster for 100 so i may just get that instead and save the time and trouble of tearing down that master cylinder.