LMC for cab-to-frame shims?

[In The Ten Ring]

My shims were toast (all but 1 of them). Has anyone ordered cab-to-frame shims from LMC? How were those?

UPDATED. See post below.

[hugger6933]

I would think it would be hard to mess up a body shim. Have you tried to see if they are still to be had from GM? I know I had a couple of drawers full for the then newer style truck[88-98] and still have a bunch but they are way big for that.

[In The Ten Ring]

The two front shims are on a 12 week backorder! YIKES! (LMC)

Unless I can find a pair from someone on here, I am going to make my own....which means getting my dad to show me how to torch cut then shape them to size and drill the holes.

I was able to order the rear shim.

[Keith Seymore]

For my own education: were there shims at every body mount location?

The reason I ask is because during the squarebody era ('73-87ish) we shimmed to fit; we only added a shim to a body mount location to help with fit and finish or to add preload to a specific mount.

K

[In The Ten Ring]

Originally Posted by Keith Seymore

For my own education: were there shims at every body mount location?

The reason I ask is because during the squarebody era ('73-87ish) we shimmed to fit; we only added a shim to a body mount location to help with fit and finish or to add preload to a specific mount.

K

I hope somebody in the know chimes in.....I was under the impression that individual trucks were shimmed on an individual basis but now I think not. Anyone?

[In The Ten Ring]

UPDATE!

I found a local machine shop (never knew he was there and I drive by there often) that can do all 3 shims for $18.00 and he will include the steel. I cancelled my LMC order.

My dad's torch set is 30+ years old and it's rather hard to get to with all that junk in the garage.

[48richard]

Interesting thread. I just installed new rubber mounts from the Truck Shop, and found I needed to shim the rear mounts to get the cab properly aligned with the bed. However, the ride is definitely different - harsher - now than before. I don't know whether this is the shimming messing with the pre-load on the mounts, or just the difference between the old and new mounts. Any opinions?

[Custom 68]

I just made some shims to get mine where I wanted it to line up correctly. I think I remember I just had to do the rear ones also.

[Keith Seymore]

Originally Posted by 48richard

I don't know whether this is the shimming messing with the pre-load on the mounts, or just the difference between the old and new mounts. Any opinions?

Both.



K

[WIDESIDE72]

Originally Posted by 48richard

Interesting thread. I just installed new rubber mounts from the Truck Shop, and found I needed to shim the rear mounts to get the cab properly aligned with the bed. However, the ride is definitely different - harsher - now than before. I don't know whether this is the shimming messing with the pre-load on the mounts, or just the difference between the old and new mounts. Any opinions?

How tight did you tighten them? I have redone two trucks and just shugged them up good. I would think that all of the "give" would be goen if they were overtightened. Sorry i cant give a before and after comparison as neither truck was road wirthy with the old bushings.

[In The Ten Ring]

WIDESIDE72 is on to something. I asked Wes over at Classic Heartbeat about it and he said that people overtighten their bushings, which negates the reason why we use bushings in the first place.

If I recall correctly, he advised to "tighten until the bottom washer touches the bushing then turn 1 more turn."

[hugger6933]

The shim should have been used by the General on a as needed basis and the new cab mount with a harsh ride quality could be from maybe a different rating of the plyability of the material. I know fro the hundreds of cabs and core supports that I've put on if you tighten the mount too tight it will fail sooner than it should because it will cause the rubber to bulge outward and that is where the failure will start. Now as far as the availibilty go to the lumber store or tractor store and buy some large washers if you are desperate and jack up and install them, not quite as good but just as effective. Jim

[48richard]

I torqued them to factory spec from the service manual. I forget what that is, and am out of town so I can't check.

[colgad]

I would like to know the torque specs too! Thanks!

[48richard]

Ill be home Saturday, and look it up if nobody gets there before me. But, the torque will not affect the bushing pre-load. You are tightening the bolts/nuts up against the spacers, and it it the length of the spacers relative to the thickness of the rubber mounts that determines the pre-load.