[ihc] Master Cylinder R/R

[BCKTHD@xxxxxxx]

IH all, 
Sorry for lurking so much lately and not chiming in. School and the new house 
have all of my time.
I am planning for some much needed TLC on a Scout this weekend.
I'll be replacing the master cylinder (77 S2 304/T18) as it's been draining 
out of the rear reservoir and leaking out between the MC and the power booster. 
It looks like its been running down the front of the booster. Not sure at 
this point if it's actually made it inside the booster or not.

Been a while since I've done this and was wanting a quick refresher.
How can I tell if brake fluid entering the power booster has rendered it 
useless?
I'd like to get away with just replacing the MC for $18.00 (NAPA #TSM101339).

Thanks,
JasonR