The Stovebolt Site Forums The Parking Lot Big Bolts Late brake Booster on '42

Has any one used a later firewall mounted brake booster on thier Big Bolt with any success? I have the pedals out of a '70 1 ton and want to mount them on the inner firewall. I need a pretty good sized booster to take the place of the Hydro-vac I would imagine? This is a 6x6 so there is another 2 slave cylinders involved, 6 of them. What have you used other than a Hydro-vac?....thanks, I know someone has been here.

Hy 1936only, it is more a case of having a large enough bore master cylinder to move the volume of fluid required in the stroke available from the booster. Once the system is full of fluid, and the brakes are adjusted up to where they should be, there should be no problem. Where the problem can come from, is not keeping up with your manual brake adjustments, hope that helps.

So if I borrow a booster from say a 5 ton truck in a bone yard would I be ok? I've seen guys put on small car boosters and they can't stop. The bore size is the issue then and using the vaccum booster of a large truck should do it if my replacement bore is as big or bigger than the original I should be ok, provided I keep on top of my adjustments, correct? It would be better to use the entire brake and clutch assy. from the donor for geometry too I suppose? Thanks for the response 3B....Rick

Hy 1936only, If you can find a booster/master cylinder from a tandem that would be your best shot. However trying to find a vacuum booster system for a tandem may prove difficult, most hydraulic systems one ton and up have been Hydroboost for a few years now, good luck.

If you go with a modern hydroboost system you will be much happier. The amount of room needed on the firewall is less and you can even make room under the floor for a hydroboost system. The down side to going under the floor is the length of the lines that go to the pump mounted on the engine.

Thanks guys, I've got literally tons of room for any system. I will look for a tamdem set up. I was missing any hydro-vac system when I picked up the truck. I'd love to put in an 80's brake set.I've got some good heavy truck bone yards around this logging town.....thanks again guys I'll keep you informed as to what works.