[Spridgets] BE MC Question

[WFO Herb]

In conjunction with the "BE Drum Brakes" post....

When I sent the master cylinder down to Sierra to be sleeved, I sent an
'extra' I had...NOT the one out of the car.

Here's the problem:  The fittings leaked; brake and clutch.  No amount of
tightening helped (within reason, of course).  Dustin (my son) came up with
the idea of using o-rings to see if the leaking would stop, which it did.
Good temporary fix.

Question:  Why are the fittings different?  Was the BE style MC used in
other applications (cars)?  Perhaps a change in fittings came about in
following years???

Got me stumped!

Herb