Shackle lift vs shim size

I have about 2-1/2" shackle lift on a 74 CJ5 with original springs. Anyone have the same and know what axle shims to get the caster back? Ball park?

 

how long are your shackles from hole to hole iv been trying to find out because i plan on doing the same thing

thanks in advance

josh

 

my 2 cents is not to use one. i installed a 4 in lift on mine and the shims made my steering wander. as always, i read the direction after the lift is installed and the directions said not to use shims in the front. needless to say, i took them off

 

I put 3 degree shims on after a 2.5 inch lift. It seemed to help some, but I still can't get the wheels to return to center during a turn. I would like to try 5 degree shims and see how that helps or hinders, but haven't as of yet. I think castor should be around 5 degrees total.

High5

 

Someone will correct me if I an wrong; but I don't think a stock 74 CJ had much if any caster set to the knuckles from the factory. That is just the way they drive. If you really want to fix caster, then wait till you have the suspension the way you want it, and then grind off and re-attach your knuckes to 5 or 6 degrees. That way you do not point your pinion toward the ground. Honestly, I would put it way down on my to-do list and just make sure all of my steering components are in good shape.

 

No shims on a stock CJ. The caster angle is welded into the axle. There is some caster, but I don't recall the setting.

I would advise you not run lengthened shackles. If you do, the only way to tell if you need to change the caster angle is to measure it (at an alignment shop). A set of well-designed lift springs should preserve your suspension geometry: your Jeep will drive right, and you won't need long shackles.

CJ-X has it right (IMO) - if you are close to stock, make everything right first, and your Jeep should drive fine. These Jeeps were very stable on the highway when new, and if everything is in good shape, they should be now too.

 

My Cj6 had a PO installed shackle lift when I got it. I never got to test drive it because it wasn't really running when I found it. After I got it going I was horrified by the road manners. It was all over the road, had no return-to-center, and followed every groove, dip, or lean in the pavement. I thought I would never be able to drive it on the road.

One weekend I did ball-joints, tie rod ends, spring/shackle bushings, and every other steering related moving part I could find. It helped, but not enough to get on the interstate.

The next weekend I removed the 'scarey-shackles'. It immediately became stable and friendly. It drives with one finger down the worst roads I can find. Rock solid, predictable return-to-center, no wander. Caster is the key, and longer shackles are the enemy of correct caster.

These vehicles drive like %^&*(%& on the road because they're 35+ years old and have been hacked on. They don't have to be unpleasant to drive. If they are maintained, the stock geometry works very well and can give you a well mannered highway vehicle that still performs off-road.