I have a pretty bad brake fluid leak where the master cylinder seems to connect to that round disc (sorry). Is there a gasket or something that could be bad?

 

Ok so is it possible that the master cylinder could leak into the brake booster and some cause the engine to ever so slightly rev? If that is what is happen

 

No gasket. You're best bet is to go to the auto parts store and get another master cylinder. Be sure you bench bleed it per the instructions before the installation.

 

Remove the vac hose from the brake booster and plug it with a bolt or what ever, start the truck see if runs better (don't drive it as it does not have power brakes) if it runs better get a new brake booster first, master cyld might be fine.

 

I don't think so merc because the brake fluid is cOming out of what looks to be the master cylinder and then runnin down the brake booster. The booster doesn't actually have fluid in it correct? So the leak has o be from the master cylinder. Plus the rev is almos un noticeable. Like it might be going up 25 Rpms. So I just doesn't think it's the booster. Also how difficult is it to change the master cylinder?

 

Not bad at all. Just have to make sure you thoroughly bench bleed it before installation.

Probably wouldn't hurt to flush the entire system either.

 

It's a five minute test up to you though, if the booster is leaking vac it will pull brake fluid out the back seal of the master cyld. It should be ez but s*** happens, always be ready to run into other things. Make sure you have a flare nut wrench to fit those lines and bleed the whole system back to front. So start spraying down the bleeder screws now.

 

Ok the master cylinder is done and primed and the system is bleed. It is about 0 degrees so I'm done for the night. Bbbuuttt the abs and brake light are on. Any ideas? I'm not losing fluid anymore. Could it be that some electrical got jarred? Thanks!

 

Proportioning valve out of adjustment due to replaceing master cylinder. Gotta bleed it to balance.

 

Ok thanks I will re bleed it again tomorrow. Its drive able though as three of the 4 brakes were bleed so I can get it back to the farm to work on it.