Soa And Steering Issues

I am now figuring out my pitman arm now. On the quote above. When the suspension compresses, it will travel upward and to the front of the Jeep. With the shackles at the front bumper and fixed mount to the center of the Jeep. I guess when the suspension expand it would move the axle to the rear of the Jeep. Am I think right on the axle movement. How far do you move the connection point of the drag link to the pitman arm from the tie rod ?

 

I am under the impression that you want the pitman arm end of the tie rod just barley higher than the drag link, like 1 degree.
The reason for this is to maintain driver controlled steering under braking or bumps. The tie rod moves through an arc when the suspension moves up and down. Normal driving operation might swing degree up, neutral, degree down when stopping. This should provide a nice straight drive.
If the angle is too large ( pitman arm is way higher than the drag link) when a bump is hit or hard braking causes the chassis to travel down, the tie rod pushes the steering knuckle towards the right and the jeep follows. The driver then has to counter steer left and the jeep is darting all over the place. The more sever the angle the more exaggerated the problem will be. These jeeps aren't race cars, but they can be made to drive very good.
My pictures are of a 2 hole knuckle setup but it is the same if you have a single hole kunckle, just imagine the connection being in the drag link.


From the center of the tie rod end to the front of the drag link I am right at 3-1/4".



I realize that this is a spring under setup, but this is what you are trying to achieve with either under or over setup. There are some setups out there that will allow you to achieve a high steer with a D30.
The Z link tie rod is designed so that the tie rod doesn't hit the springs. It does nothing to correct bump steer.
Stiff front springs and steering stabilizer shocks like shown in earlier pictures in this thread... will help hide bump steer issues but not solve them.

 

Tie a string to the fixed spring eye bolt, and pull it forward and pinch it at the front of the tie rod tube. Swing it up to your pitman arm while holding it taut. I’d give it an extra inch or so just to allow for variables.

 

If I may entertain/educate with a demo from my ‘78 SJ Cherokee that I converted to SOA for $6 demonstrating FULL bump steer on a small jump while the steering wheel was held straight ahead the whole time. Note the steep draglink angle just below the missing driver side headlight. A ‘Z’-shaped draglink was used to get under the passenger side spring. This was not a rock crawling rig though and only the rear axle diff was Miller-Locked so it survived just fine. But as shown, that’s how far it would steer to the left during suspension extension travel and vice versa during compression. Landings were always entertaining to observe including from the driver’s seat. -Hônes

 

On the way to SOA on the ‘71 R-II, I first went with 59" Waggy axles from a 1970 Inline 6 cyl SJ donor rig that had a D-30F closed knuckle and offset D44, both with drums. I wanted width over height to start with but discovered the extra articulation from width necessitated either more height or bump stops to prevent the tires from clearancing themselves in the fender. I wish I had a better shop than a dirt/gravel driveway and jack stand supports that weren't cinder blocks (not really recommending this!).

Without the flat top of a 44’s knuckles, I didn’t have a solution for high steering on either the original narrow track 27F or the Waggy 30F. Rebuilt these with Detroit EZ-Lockers and 5.38s and crawled it that way (gently!) despite the T-14's poor crawl ratio.

The passenger side spring does have to get outboarded as was noted by others. Here’s my version of that process with what scrap I had lying around. In the first pic below, the rear offset Waggy 44 was already installed and was very easy to do once new perches were welded on. Later on, I converted a 6 lug Waggy D44F to 5 lug by swapping on Ford Bronco hubs/rotors and milled the tops flat and had some high steer arms made for both sides with square key ways in each to take some of the load off the studs. The knuckles had the female keyway running front to back and the high steer arms had a square ridge sticking out running down the undersides.
-Hônes

 

Some really great replies and suggestions for improvement over my current set-up. I can attest to the bump steering both on and off the trail... I did get repaired (and beefed up) the current drag link. Steering setup on the list of upgrades! Thanks for all the suggestions and ideas!