Castor Shim Installation - anything special I should know?

[Ezra]

My truck has a shackle lift and is sitting on 33' tires. It has no shims, and has always been a bit squarely. I picked up a couple 6* Shims from CCOT (I believe my lift is 2.5" but to be honest I am not certain).

I wanted to install the shims tomorrow, anything special I should know? Any tricky parts? Any Special Tools.

I assume its just an issue of removing the tire, lifting the corner. Removing the u-bolt nuts, lift the axle, insert the shim thick side forward, then tighten everything back up.

Am I missing anything?

Thanks everyone.

 

[brian]

The chassis will need to be suspended not just a corner.
The axle will have to free on both sides.
6* shims are going to be too much....without power steering on your rig, it will be almost impossible to turn the steering if the vehicle is not moving....even then it will be a display of strength.
You'll only need somewhere around 2* degree shims.
Best approach is to measure angles before just adding shims.
Find a level surface to park on.
Remove the front prop shaft entirely.
Magnetic protractor on the transfercase output flange and the pinion flange on the front rear . Transfer should be right around 90*
Front pinion will be a few degrees away from 90.
Shim degree will be whatever the difference between the two measurements is.

 

[71FFJ40]

Your best bet is to bring your truck to an alignment shop and have them measure your pinion angle.Add shims based on the measurement.
Shims,if needed will be placed under the springs.Spring pin needs to be removed and pin goes through shim to hold it in place.
You can just loosen u bolt and lift spring pack away from the axle.It's not complicated.First determine why/if you need shims and what thickness before just installing them.

 

[Mr Cimarron]

I got mine from Valley Hybrids, @orangefj45, along with some longer pins. I used a simple angle gauge to get a measurement. I was at negative 3 after 2" lift. Georg reccommended 4 degree shims. Drives awesome now.
Install for me was easy since the axle was out from the vehicle.

 

[1911]

Like the others said, don't guess. Measure it and only use enough shim on the front to get the steering caster to spec. The thicker the wedge on the shim (the more angle *), the worse your u-joint working angles will be, but on the front that is less important than the caster, since the front axle is not often driven (powered) on the road.

Rear axle is the opposite - you want to shim that one enough to make the working angles on both u-joints equal and opposite.

 

[orangefj45]

Most 2-3" lifts require 4 degree shims.

We stock the billet steel shims in 2, 4, 6 and 8 degrees along with the longer center pins.
Stay away from the aluminum shims, they do not hold up.

And make sure you use a digital angle finder. It's your steering we're talking about. So don't take chances.

Georg @ Valley Hybrids & Cruiser Brothers