We usually prefer to mount a vacuum brake power booster on the firewall but it doesn’t work in all instances. This is one of those situations, we have a customer who brought us his Ford F1 frame and cab. His plans with this build are to use a Ford Powerstroke 7.4L diesel engine and a reasonably heavy duty suspension. The frame supplied was pretty bent up and required some extensive frame rail straightening. Once within spec, we boxed the rails and added a 1.75″ DOM tubular crossmember with enough room for the rather large automatic transmission and a crossmember kit to accept the Dodge Dakota components. The owner has been doing some research into using Dodge Van brake rotors to give him a 12″ X 1″ rotor with a 5 on 5.5 bolt pattern to stop this very heavy power plant.
To round out the upgraded brakes we need the rest of the system to be just as serious. Given that diesels do not have manifold vacuum our choice is to use an electric pump or the Hydro-boost system that uses power steering pump pressure to give you some serious assist. The tubular structure under the cab restricts pretty much any braking system to be installed between the frame rails. So our option is to utilize the unused space outside of the frame rail. We did this same trick on the Dynacorn build in the summer of 2008 and it works extremely well. We used the stock brake pedal arm and location to retain the original look. This put the pivot through the middle of the body mount. It was much easier to measure it up and replace it.
Making the stock pedal work for us in this situation we used a 3/4″ X 36 spline steering shaft and coupler housed in a tube with bronze bushings for long life and durability. The splined shaft also gives us the ability to service the system and make it easier to remove the cab if ever need be. Or just to make putting it all together when painted less of a chore. The old clevis mount was band sawed off and the bushing hole drilled out to 1″ to accept the steering coupler and TIG welded into place. A bit of machine work on the shafting for bushing clearance was need also. With all the components mocked into the proper positions a bell crank arm was fabricated from 3/8″ Cold Rolled Steel and welded to the shaft.
The final connection was from the bell crank arm to the Hydro-Boost pushrod. I used a shoulder bolt, spring wave washer and a bronze washer along with machining a small bushing to compensate for the differing sizes. In the end we have a very durable and serviceable braking system that should be more than up to the task.
If you’re interested in having this sort of work done, drop us a line!