(mostly for rick)

I got a mc for my 83 from my FLAPS for $50 - complete with a very detailed
'pressure test report' from the remanufacturer (Beck-Arnley).

Incidentally the symptoms that led me to replace the mc were 

Van stopped great but every 30 applications of the brake or so the
pedal would sink about 1/2 way to floor, one pump would restore
original (excellent) braking action. Diagnosis was compounded bythe fact that
it never happened to me , only to SO who drives the car infrequently (i 
probably only use the brakes 10 times on the way to work!)

I wrestled with this for about six months, dutifully bleeding every
wheel every time she reported it - after which it would go away for a 
month or so and then return. Finally figured it had to be mc, replaced and
hasnt happened since  :-)

People driving 70s and early 80s busses/vanagons take heed - imho the
$50 three hours of labour is very good insurance if you dont know how
old your mc is. Brakes (particularily hydraulics) are one of the systems
you ideally want to repair before they fail! Also a good time to replace all the brake fluid  - has anyone ever bought a used car that had nice looking
brake fluid -  i sure havent ...

btw my FLAPS is a CAR-QUEST distributor, but anyone who sells Beck-Arnely
should carry the above mc. Also sells me FAG bearings, ANSA mufflers for
my other VWs