The HydraVac uses engine vacuum to provide pressure boost to the stock master cylinder much in the same way that modern brake boosters work. The only difference is the HydraVac is separated from the master cylinder whereas the modern master cylinders mount on the front of the booster.
I can see no reason why the HydraVac could not be used with disc brakes, except that the rear brakes if they are drums may need a pressure regulation valve fitted to the rear feed line to prevent lockup.
Good Luck with your search for the HydraVac unit, they were fitted to many cars and trucks from the early fifties through to the sixties.
I can see no reason why the HydraVac could not be used with disc brakes, except that the rear brakes if they are drums may need a pressure regulation valve fitted to the rear feed line to prevent lockup.
Good Luck with your search for the HydraVac unit, they were fitted to many cars and trucks from the early fifties through to the sixties.