Here's the end of the piston rod that attaches to the pedal linkage.
Make sure to install the jam nuts in the same position on the new rod as they were on the old rod so you don't have to fool around with the adjustment when you're done. This assumes that your original MC rod was adjusted correctly, If the brakes were working and pedal height and travel seemed right, don't mess with it.
I don't have a good picture of the pin but you can see it in the last two photos. The cotter pin can be seen sticking out of it.
1950 Chevrolet 3100 (Ol' Roy)
1939 Packard Standard Eight Coupe (The Phantom) | 1956 Cadillac Coupe de Ville (The Bismarck) | 1964 Ford Galaxie 500 coupe |1966 Ford Mustang (Little Red) | 1969 Pontiac GTO (The Dishpit) I 1979 Ford F-100 | 1976 Ford F-150 (Big Red) | 1995 Ford F-150 (Newt)