87 745 brake fluid on top of master cylinder?

I put a booster on my 87 turbo wagon the other day, it was obviously
dead.

I adjusted the piston to match the protrusion out of the original
booster, so in theory that's correct.

Noticed the last couple days after a day driving the top and sides of
the master cylinder are slightly wet with brake fluid. It's got to be
coming out of the cap, but why? The gasket looks decent on the cap,
could it be as simple as a bad gasket on the cap? Any other technical
reason it'd do this?

Thanks again..

 

You may have just overfilled it a bit, wipe it down and keep an eye on it.

 

I had it filled to the Max line, I thought. The brakes seem to work
well enough. Pedal is a little lower than I'd have liked, and a quick
stab gives a second or two of slow sinking before it stops. I have no
point of reference as to how they should feel really as the booster
was shot when I got the car.

 

and seated.