55.2-59 1958 Apache 3800 Hydrovac

[leegreen]

Originally Posted by 58ApacheGuy

Thanks. Have been considering this resolution. Problem is with frame mounted master cylinder, if I mount the vacuum booster combo, I'd either have to convert to automatic transmission, or convert manual clutch to hydraulic clutch, which I haven't even begun to research.

does this work with factory clutch setup?
https://www.holley.com/products/brak...ORN755DISCDRUM

[dsraven]

Forgive me if I'm wrong here, but the hydrovac boosters I remember had a master cyl that was foot pedal operated and that sent a signal to the hydrovac booster mounted somewhere else and it also has master cylinder on it that operates the brakes. Really, a hydrovac from a newer truck should be able to be serviced on your old truck. Just do a bore size comparo and go from there. Maybe also run a vacuum reservoir tank with one way valves so you don't run out of vacuum. Really though, if using the brakes, the throttle should be closed causing a higher vacuum. It depends on rpm then as to what vacuum you actually see.

[mr48chev]

Originally Posted by dsraven

Forgive me if I'm wrong here, but the hydrovac boosters I remember had a master cyl that was foot pedal operated and that sent a signal to the hydrovac booster mounted somewhere else and it also has master cylinder on it that operates the brakes. Really, a hydrovac from a newer truck should be able to be serviced on your old truck. Just do a bore size comparo and go from there. Maybe also run a vacuum reservoir tank with one way valves so you don't run out of vacuum. Really though, if using the brakes, the throttle should be closed causing a higher vacuum. It depends on rpm then as to what vacuum you actually see.

You are correct in how they work and I'd say correct in that one off a later model would work and might be a better option.