Axle Shim Questions

Posting here as well as the 2nd gen forum.

I have the dreaded driveline vibrations post-install of a new leaf pack. Trying to figure out what I'm getting myself into to correct. Any help would be appreciated. Man this sucks.

1. When axle shims are installed it removed, does it require an alignment?

2. How much longer does the center pin have to be in order to accommodate a shim without changing the center pin to a longer one?

3. Do they make shims that don't require a longer center pin?

4. Does changing the center pin require removing the entire leaf?

5. To rotate the pinion down, I' am assuming that I need the fat part of the shim towards the front?

Thanks,
Jay

 

I'm getting ready to do this tomorrow.

1. Nope. Have the thrust angle checked next time you do an alignment but you should be fine.
2. Dunno, I got my shims from Toytec and they came with new pins.
3. Dunno.
4. No. It's nearly the same process as installing an AAL. Though I have yet to find out if it requires removing the shock.
5. No, the sharp end goes to the front.

You should also get new U-bolts. I got the 9" ones from Toytec just to be safe.

It does suck. "Kits" should be sold with the shims in the first place. Now I gotta pretty much do the whole back end again.

Were in MA are you? I was born in Northampton, spent a lot of time around there.

 

1) No

2) Axle shims come in different 'degrees' (angle). The higher the degree, the thicker the shim will be. The smallest shim you can get is like 2.5 degrees. I had a set of 2.5 degrees in my 96. In that small size....you might not actually be bolting the shim to the leaf pak (atleast, the ones I had didn't) - so the centering pin length is irrelevant. So, it depends on the shims you get. Personally.... I would get new centering pins just for safety. They're cheap. Get longer than what you need because you can always cut them shorter after installed.

3) See above response. Depends on what shims you get. Try not to buy aluminum shims. Get steal shims if you can. Aluminum is soft and can 'flatten' over time. I personally never had trouble with mine - but I've heard others have.

4) If you get the smallest shim that doesn't 'bolt' directly to the leaf pak...you can install the shim without touching the centering pin. Simply remove Ubolts, separate the leafs from the pad.....install shim... and make sure some of the centering pin HEAD is exposed below the shim itself.
Drop leafs onto pad and make sure the 'head' of the centering pin enters the hole in the leaf pad. Install Ubolts.
If the shim bolts to the pak - you can keep the leafs on their hangers. Use C clamps to hold the leafs at both ends. Remove Ubolts. Separate leafs from the pad. Remove centering pin. Install shim & centering pin. Drop leafs down onto pad (make sure the head of the centering pin enters the hole on the pad). Install ubolts.

5) This photo - depends on where the front & back of the truck is (you can figure it out)

 

If you use the slide in style shims your centre pin head may not extend far enough below the shim to allow positive seating into the alignment hole on the axle , in that case you need centre pin collars