DOT 4 is backward compatible with DOT 3.

DOT 5 silicone fluid is superior to all of them but you can't mix it with the glycol based fluid. If you're installing an entirely new brake system with all new components, use DOT 5 if you want to.

Last edited by Otto Skorzeny; 11/02/2022 5:11 PM.
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)