I am in the process of building a ‘28 RPU and have questions about the steering linkage. No doubt thousands of hotrods have been built in the last 75 years with the same suspension that I am using. I am using a 4” drop axle with a reverse eye transverse spring and the drag link seems to be at a ridiculous angle (from the Pitman arm to the steering arm it climbs like Mt. Everest. Am I missing something? I had planned to use a “dropped” steering arm which would have helped a little but it hits the axle so is a no-go. Advice would be welcome and pictures much appreciated.
I am using an F100 box but that doesn’t change the steering linkage because the Pitman arm is in the stock location and orientation.
I posted the box info immediately after my first post but for some reason it did not show up at that time. I am using what folks call a “shortened” Model A Pitman arm, and what some folks call a ‘33 Pitman arm. The F100 box was adapted to use a square sector shaft specifically to replace the OEM box. The Pitman arm was then shortened to be the length of the V8 Pitman arm Henry realized in 32 that the current box required too much effort to steer (probably the result of the wider tires that were then in use) so they went to this shorter arm. The pitman arm uses a tapered ball with the ball being on the outside (wheel side) of the arm. So, there are many hundreds of cars out there with this exact set up, I didn’t reinvent the wheel, I just copied others.
It's not unusual for the drag link to run up hill in many side steer setups. The drag link running up hill isn't an issue in itself as long as the pivot of the axle and drag link are in the same arc. If not bump steer is an issue.
https://www.jalopyjournal.com/forum/threads/steering-drag-link-angle.1142753/ Perhaps the picture in post #10 on this link may help.
Is the front end going in from the top or bottom? If you can get it in from underneath it will help matters. Bending the steering arm so it is as low as possible also will help. Some pics would be useful.
Do you have a dropped steering arm - or a straight hairpin one. These popular style steering arms will raise the front of the drag link up pretty high especially when used with an F-1 box. Flipping it over and putting the rod end in from the bottom will get you a couple of inches as Mart mentioned. getting one that loops down a lot closer to the axle helps lower the front of the drag link too. entioned.
Steering arms can change the point as noted but modifying/heating bending them for your need is common. See which one offers the closest to your needed position and modify as needed.
I believe this info was developed by Pete Eastwood and has been published in the Pete and Jakes catalog many times over the years.
You might try to find a thread I posted yesterday. Steering Arm It shows a dropped steering arm installed.
Seems to me that the more flat the angle, the better. However, there are probably hundreds of early rods with the angle you are experiencing.
All of the pictures, diagrams, and explanations were very helpful thanks to Y’all. It looks to me that if a builder wanted to stay with side steer linkage a steering box with a vertical “up” Pitman arm would be the way to go however I don’t think it would work with a full fendered car (which is what I have) and I’m not going to be buying another steering box either. If I ever do this again I think that I would either use a Vega box or a rack. Thanks again
Andy, yes, that looks like exactly what I need (if I could buy one ready to go I would). Awhile back when I kinda-sorta mocked up a system like that the drag link hit the axle on a full left turn however the way my pitman arm is set up the “ball” faces out (closer to the tire) but on yours, it is on the inside and I think that maybe that’s the answer. Also, if you started with a stock length aftermarket arm, by the time you bent it into that shape you will have shortened the effective length by a fair amount which would increase steering effort but would speed up the ratio (probably not a problem). I don’t trust my skills enough to make an arm from scratch. Bend one to shape I’m ok with.
You can make it with a little out side machining. You just need to have the bars ends machined down and threaded. The socket can come from most any tie rod or spindle. Bend the rods and weld it up. I would for sure add webbing (boxing) in between the rods and also add the side pieces that go to the lower holes. It stabilizes the whole thing and reduces bending stress on the top bolts. I used some pipe for the tubes for the lower bolts. Try it! A stock replacement arm won’t work in my opinion. It would end up too short and wobbly. It would need the side braces and they would be hard to add.
The Jalopy Journal
