Sounds like the power brake booster is bad, that is what the master cylinder is bolted too. There is a rubber hose that has a plastic valve in it were it snaps into the booster, Pull that rubber hose out of the booster and off of the engine, Now the end that you took off the engine. You should be able to suck through the line, but not be able to blow through it. If you can then replace the valve, It is a one way valve.
If that is all right then hook hose back up to the engine and start engine, You should hear a major vacuum leak at the valve end, put you finger over the valve and it should stop making noise and engine should smooth out. If it don\'t the rubber hose must be leaking or the tube on the engine were the hose hooks to is stoped up.
Answers & Comments
Sounds like the power brake booster is bad, that is what the master
cylinder is bolted too. There is a rubber hose that has a plastic valve
in it were it snaps into the booster, Pull that rubber hose out of the
booster and off of the engine, Now the end that you took off the engine.
You should be able to suck through the line, but not be able to blow
through it. If you can then replace the valve, It is a one way valve.
If that is all right then hook hose back up to the engine and start
engine, You should hear a major vacuum leak at the valve end, put you
finger over the valve and it should stop making noise and engine should
smooth out. If it don\'t the rubber hose must be leaking or the tube on
the engine were the hose hooks to is stoped up.