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Does anyone have any idea,hints,anything on how to hold a cj with soa and 36" 16 tires between the yellow and white lines on the road?Ive replaced shocks with nitros,installed a steering box brace,moved my steering shock every wich way and still cannot controll it over 40mph.Theres got to be some of yall with this prob and have conquered the prob.If its homemade, great pics would help also. Thanks fellas.
This is one of the big "gotcha's" when you do a SOA.
If your Jeep wanders uncontrollably, it's most likely a caster problem.
Most likely when you installed the front spring pads, you rotated the pinion upward for better angle, that rotates the knuckles forward, giving you a zero or negative condition (top ball joint forward of the lower). Optimum is 4-6 degrees of positive caster (top ball joint behind the lower). You can buy caster shims from 2 to 12 degrees and install them with the wide end forward for a test. This will of course swing the pinion back down, so the u-joint angle will be affected. I don't care for leaving them in though, because most are aluminum, and if they wear, they can slip or crack, make the u-bolts come loose, and could cause the axle to shift.
If you can live with the u-joint angle, the best bet is to cut and re-weld the spring pads in with the caster set correctly. If the u-joint angles are too steep, and you need the pinion tilted up, then the other solution is to grind the knuckles loose from the axle tubes, rotate them until caster is correct, and re-weld. The problem here is you need to be within 1 degree side-side, or you can end up with death wobble, which is worse than your wandering problem.
When I built my SOA Dana 44 for my CJ, I used a GM truck housing (already set up for SOA). The pinion angle is about 0 on a GM, and I needed about 8 degrees upward, which would have given me about 4 degrees negative caster. We ground the knuckles off, machined 8 degrees into the cast pad, then installed the axle in the Jeep and set it at ride height. We tapped the knuckles back on, and set the caster/camber using a rod that fit snugly in the ball joint holes and a digital level. We tacked everything in place, then removed the axle and fully welded it, being careful not to apply too much heat to any area, so it didn't twist or distort.
Took it to an alignment shop when it was done, and camber was dead on, caster was 5.5 degrees on one side, 6 on the other. I've driven as far as 400 miles on the highway, and never had a problem.
Not an easy fix, but the only way to do it right.
Bob
tufcj
Are you still running the stock steering column from the box to the firewall? Sometimes there is a lot of slop in that bell shaped steering shaft coupler down at the steering box end. Flaming river or borgensen makes a replacement that uses a needle bearing u-joint instead and completly gets rid of the slop. Get a buddy to crank the wheel back and forth while you lie under the front and look for things flexing. Sometimes the spring hangers have a broken bolt.
I have a SOA on my cj5 with 4 inch lift springs. When I welded on the perches I made sure they were parallel to the old perches so that my caster would be the same. I am runnung 36 inch tires also. I can run down the road at 80 mph with no problems. I would check the caster.
The thing that helped me gain control more than any other improvement was installing a new steering box mount. The old 2 piece design is garbage. Between that and a new steering shaft, my steering was top notch on my CJ... well, top notch for a 30 year old CJ at least... :)