RE Steel Degree Shims, purpose?

I was wondering what these shims are used for? I know its to help set pinion angles, but will that help my XJ'S rear driveline angle and/or can it weaken the center pin?

They are used to lessen driveshaft angles by adjusting the angle of the pinion in its relation to the spring pack. (IE pointing it up 2 to 8 degrees)

It is placed in between the axle spring perch and the spring.


HTH

In order to use the steel RE shims, you have install longer center pins (which normally come with shims). The shim becomes one, with the leaf spring. The shims cannot just be inserted between the spring perch and the leaf pack.

Install some C-clamps on each side from the center pin to keep your leaf pack together. Allow enough room to be able to install the shim. Once you have the springs clamped down, remove the stock center pin. Run the new longer center pin through the shim hole, and then install on the bottom of the leaf pack. Apply nut, tighten, and remove C-clamps.

Ivan

Ok, sounds good. The reason why I ask is bc I getting ready to instal a 4" lift to my XJ's rear and I am conserned about the pinion angle causing vibratrions. I was thinking about installing the shim rather that a trans. drop, or CV/SYE to help reduce the expected vibratrions. I take it that it will not weaken the center pin.

They won't weaken the center pin. Using shims instead of a TCase drop or SYE/CV shaft will not fix anything. The shims are to be used with the SYE/CV shaft to point the pinion toward the TCase. Without a SYE/CV shaft, the pinion of the axle needs to be parallel to the yoke on the TCase. Here is some good reading for you: http://www.pirate4x4.com/tech/billavista/PR-shaft/index2.html

When it comes to fixing vibes, there are two ways to do it, the cheap way, and the right way. If you have a 95 and older XJ, chances are, you may not get vibes with a 4" lift. '96 and newer XJ, better plan on getting vibes.

Thanks. I'm new with driveshaft talk/knowledge. Yeah, my 90'XJ has no vibrations, and my two friends with their 3" lifts, (same height as mine) on their 99' and 00', have vibrations. So, maybe this new lift (4" rear and 4.5" front) I put on, it will not have too much vib.