I'm putting together a traditional style Model A hot rod. Trying to get my front end all finished up. I ran a tube style drop axle and am using a 4 bar to the frame. I was planning to use the stock steering on the Model A, but the upper bars on the 4-pin and the steering will have interference. If I could extend the square shaft on the steering box out an inch or so, it would all clear. I can switch over to the Vega box and use the cross steering if I need to, but am hoping to use the original stuff. Any thoughts or ideas? Thanks!
OEM 'A' steering is push pull and 4-bar isn't traditional. Vega is cross steer and would be a better option IMO. 'I' beam is traditional as are split bones [Hairpins?]. I believe that you'll create more problems trying to fit a square peg in a round hole by proposing what you are, bump steer etc. Things need to be parallel to work
Are you talking about extending the shaft that the pitman arm connects to, for clearance with the 4 bar set up? I guess it could be done, but you wouldn't want me to do the welding. You might be happier by adapting an F1 or F100 steering box, but you still have the clearance issue. If you keep the 4 bar you'd probably be better off with a cross steering set up. -Dave
Put up pics from different views so we can help. It seems like you are too far into the build before you were thinking about the pitman arm and drag link clearances. You should not even think about extending the Model A square end of the sector shaft, as it adds more loads to the components, ....and if you bring any pitman out further, you might not be able to steer tight to the left if the tire hits the drag link. In hindsight, if you chose a beam axle, you'd use split bones tucked under the chassis at the rear ends, to make tons of space for the drag link and pitman arm. But good pics might get you out of the issue you have with what has been built so far. .
I think the Vega box might be the way to go, unless a f 100 box has a longer shaft dont know about that.
When P-Wood, Pete, and Jake designed the 4 bar for use on Model A's, they designed it around a bracket for the Mustang steering box; this design laid the Mustang box 90* around on its side, (from its 'Mustang position', which pointed the sector shaft straight down) The new 4 bar position for the Mustang pitman arm was 'up', which ran the drag ling parallel to the 4 bars, with the point of radius of all being from the same. This was a simple way to incorporate steering box and the 4 bar bracket into one, and eliminate the dreaded 'Bump Steer'. (also, 'shimmy', 'shake', and finally, 'Death Wobble'!) Beware. Vega boxes were introed right after, for '32s, '34s, etc., but incorporated sliding 'Double-D'- shafts/tubes, U-joints, and panhard bars...or, for some, the dead perch. A Street Rodder I knew ordered all the Vega parts to 'cross-steer' his '32. His living room looked like a swap meet. I asked, "Are you gonna put all this stuff on your Deuce?" He seemed to look past me...
I'm using an F1 box with a Model A snout welded on it and moved as close to the frame as possible and still had clearance problems with my split wishbone. I also used the snout off another steering box as a support bearing on the outside of the frame since the sector shaft stuck out quite a ways. I ended up buying a 7 degree drill bit and mounting the wishbone on the inside of the bracket and bending the pitman arm. With the 4 bar I would probably use the Vega box.
Model A Gomez.....I've been searching the HAMB for solutions to a split wishbone/drag link interference issue I believe I'm going to encounter. You're post and photos are similar to what I think I'm going to find. I have a Model A frame, '35/'36 axle, plan to use the stock Model A 2-tooth steering box if possible, and because of engine/transmission choice I need to run split wishbones. I ran out of time today to do a complete mock-up, but at first blush it appears the draglink and split wishbone might be on a collision course. To get caster into front axle without pie-cutting the A wishbone I have and splitting it, I had hoped to use a pair of wishbones that have already been separated. I think they're from a '37 since they have a 2 1/4" opening on the "wrist" that pins to the axle, have more bend built in for caster purposes, and they're a bit longer than the A wishbone would be. My wishbone frame brackets would land about 1/2 way between the front body mount and the front running board bracket with the '37 (?) wishbone. I'm guessing your pictures posted were "during construction" and I didn't quite understand if your drag link is mounted to the inside or the outside of the pitman arm. The photo shows the wishbone on the outside of the frame bracket, but it almost sounds like you might have re-done the frame bracket hole's taper and mounted the wishbone on the inside of the bracket, with the rod end's nut toward the outside? I hope to spend some time doing more of a complete mockup of the front end tomorrow, but these unknowns really bug me and I hope you can offer some input on what you ended up with. It might be a solution similar to what I'll need to do. Thanks Lynn
That was done back in the day. The orig 32 frame under my car came from an old time full fender car. It still has the plates with reverse taper like you mentioned. Get the bones tucked the heck under the chassis. This is so simple, and not only can a pitman swing without interference, your tire rear inside edges won't hit the bones on a full lock turn. I did not use those brackets, because I tucked mine under even further...but I left the old brackets to show what was once done. . .
I did a bit more mock up of the steering and split radius rod parts on my Model A frame. Most parts involved are listed in my post #8 above, but I'll add that I have '32 spindles on the '35/36 axle. Problem is interference of the split radius rods ('37 I believe) and the pitman arm on the stock, Model A 2-tooth steering box. FWIW, the radius rods are 40 1/2" long from the center of the perch bolt hole to where the wishbone was cut apart. The first photo is looking down on the radius rod toward the inside of the frame rail with me holding a Ford tie rod end in approximate position it would be in on a bracket mounted to the inside of the frame. Second photo is the interference of the pitman arm and radius rod. Mounting the radius rod to the outside of the frame would require the drag link to "cross over" the radius rod and that can't possibly work the way I see it. I don't think I could move the radius rod/frame attachment bracket far enough inboard to clear the pitman arm without getting into the bellhousing and/or transmission I'll be using. Although I'd like to retain the Model A steering box, I'm thinking I may have to go to a Vega or Unisteer cross steer setup and switch to a pair of '40 spindles I have. I've tried searching the HAMB regarding split radius rods on a Model A, and have looked at many Model A photos that might show how steering and split radius rods co-exist but haven't found anything. This really has me baffled. I thought I knew something about hot rods and how they were built, but apparently I never paid nearly enough attention to details when I looked at Model A's. I hope I'm not crashing in on this thread, but it sounds like I have a somewhat similar problem as the originator of the thread. Thanks, in advance, for input. Lynn
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