Quote:
Originally Posted by rotorwrench
The Hot Rod Works has a torque arm kit and a radius rod mount set up for the pre-1941 "long" radius rods to three point the system but I'm sure it would requires some mods to make it a better set up. If I went the torque arm route, I'd likely design and build my own set up. I like the simplicity of the buggy spring suspension so I'd either go that route or modify the T-5 for a torque tube drive as previously mentioned.
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Ah YES ...."THE SIMPLICITY OF THE BUGGY SPRING SUSPENSION"! You almost couldn't say it any more simplistically. But there are a lot of "modifiers" in our ranks that still do not understand the totality of that simplicity. There are two basic elements that must be remembered when evaluating just how Henry's "buggy sprung, torque tube system" actually works, and what is required to remain fully, and safely functional.
The first element of the system is that the whole rear end/torque tube assembly articulates about TWO points in two dimensions. The assembly is able to ROLL about the longitudinal axis defined by the point in the center of the rear crossmember where the buggy spring is securely clamped, in addition to the front end of the torque tube assembly joint approximating a point slightly in front of the torque tube bell, essentially in line with the center of the U-joint.
The REAR end of the whole assembly is able to move up and down in a PITCHING motion via buggy spring action and constraint, about the same point at the front end of the torque tube and center of U-joint as discussed above. The 'captured ball' surrounding the U-joint at the front end of torque tube serves to anchor-securely that end of the torque tube, yet allowing full articulation about that point in the center of the U-joint.
The SECOND element that is often overlooked is that the TORQUE TUBE is the member which transmits the driving force that moves the vehicle forward, or rearward in the case of reverse. The torque tube actually pushes the vehicle forward, and pulls the vehicle in reverse. The torque tube is also the member that resists any control over the rear axle housing's propensity to twist upward at the front while transmitting torque to drive the vehicle FORWARD. While driving the vehicle in reverse, the axle housing tries to twist downward in the front. This "torque-induced" movement is normally contained and controlled by the torque tube. Once the torque tube is eliminated, as in an 'open-drive-conversion', those two radius rods (formed from rolled sheet-metal) now have their work cut-out for them trying to control the TORQUE-rolling of the rear axle assembly. You've gotta remember that these two wimpy rods are now what is left to PUSH the vehicle forward, or pull it rearward as in REVERSE. And if you 'GET-on-it' hard, all bets are off! Those radius rods can fold-up like spaghetti. They were originally designed ONLY as a means of reinforcement for keeping the TORQUE TUBE at an angle of 90º to the banjo housing, via simple triangulation.
Many times when modifying an old Ford's torque tube system to subsequently perform "open-drive" duty, some of these elements are overlooked, or even totally mis-understood. If the modified system overlooks any element of the original design, the vehicle will likely drive like crap, especially when traversing odd changes in road height, like driveway entrances, and pot holes. And heavy acceleration can be especially destructive if rear axle torque is not adequately controlled by substantial members specifically designed for that function. The entire rear end suspension must function in it's entire range of movement just as well as a stock torque tube rear end.
One more thing usually seen during these modifications is radius rods being "split", spread-out, and anchored to a frame rail by a bracket of some kind. In a case like this, whenever the rear end (or front axle) is raised or lowered at one end, as if you drove one rear wheel into a deep pot hole, anything that causes the rear end (or front axle) to ROLL in alignment with the longitudinal axis of the vehicle, you are actually TWISTING those radius rods. They are only going to 'TWIST' so many cycles before they break or fracture at a mounting point, or anywehere along their length. This does not occur when the radius rod is mounted to the torque tube. NO COMPONENT gets twisted with the normal movements in a torque tube rear end assembly. If you don't understand ANY of the above, trying to SUCCESSFULLY MODIFY a torque tube system to function properly is likely not going to end well. DD
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