Roger L

To align rear wheels on my '66 I purchased the "Fork" style shims. When I look at the existing shims in car they are protruding from the opening on frame where trailing arm attaches, although they may not be the fork style shims and therefor retained by mounting bolt. This just doesn't look correct sticking out. I thought the shims (sized thickness as required) go on outside of trailing arm spacer with ENTIRE shim located INSIDE of frame and retained with a cotter pin thru the frame in bottom hole on shim. Or do shims go inside frame and are retained by frame without any cotter pin and retained by tightening up trailing arm bolt?
I can't see or feel any holes thru side of frame below the trailing arm mounting bolt for a cotter pin to enter. In addition there is literally no space outside of frame to install a long cotter pin, do I have to remove anything to see the hole if it exists? Hole should be visible on both sides of frame.
I need advice on getting the shims installed and retained properly. Does anyone have photos and or instructions on how to install them, I looked at Assembly Manual and it's not clear to me. Any help is always appreciated. Thanks for reading this, Roger

66jack

The 'fork' type are the only ones held with cotter pin...if you don't use the cotter pin they can possibly work themselves out and fall out......some people...'me' just stuff them in the pocket without pin...

The originals just hung out...

magicv8

I drilled my 66 frame to use a long cotter pin in the retaining holes that come on shims for later cars. The slotted shims are easier to work with.

The original shims didn't need a cotter pin because they had a hole instead of a slot.

Once you have the shim sets the correct thickness for alignment, they should be a "wedge" fit. You should need to tap them in with a small hammer, then torque the cross bolt WITHOUT squeezing the frame pocket.

I always found it easiest to tap in the thickest shim last, and I always lubricated the clean shims to limit rust and make installation easier.

Bluestripe67

The shims are placed inboard and outboard based on the alignment specs. The hole can be drilled about 1/2 in. above the step in the metal as viewed from the side. Dennis

Scott Marzahl

I used the fork style as well and drilled the holes in the frame on my 1967.

Avispa

Have used the fork style for 15 years without a cotter pin and they have yet to move out of the frame pocket. GM at one time sold service shims with a notch on the end opposite the fork that held the shims in the pocket. Not sure where to find those any more, but if you're concerned about shim movement and don't want to use the cotter pin, you can shape the ends of the fork type shims to replicate the old GM service shims.

rgbau140

While some have had no problem with them falling out w/o drilling the frame and adding a cotter pin, I did have mine do it once. you dont want to be driving when they start falling out because once they start, they all go (or did on mine). now the trailing arm starts moving on its own. these become interesting to drive when you have independent rear steering - the car wanders all over the road on its own.

Bluestripe67

Don't forget. You pay for the overall alignment, and it's not cheap as done by a competent shop. Then you lose them and you get to do the alignment over again. Dennis

65 Pro Vette

I use the original style shims and cut them with a sawzall not to make them look like the fork type but I cut a notch in the bottom the same size as the bolt and just hook it over the trailing are bolt. You get the best of all worlds shims that can't fall out, no need to remove the front bolt at alignment time, and full credit at the NCRS shows.

TheSaint

I have never seen any other type of shims for the trailing arms other than the one on the picture

I bought new ones for my car and i bought stainless steel. You secure them with a cotter pin thru the frame

65 Pro Vette

The original shims have the 5/8 hole on both sides and are the same square look on both sides. You can put them in anyway you want. 63 was the odd year they were slotted.

A-Snake

This is probably what you're talking about
We cut the slot at an angle to help keep the shims in place.

Roger L

WOW a lot of great advice, I particularly like the idea of notching the shims on side that should prevent them from falling out. I appreciate all the response. Thanks Roger

magicv8

The only problem with the side notch is you lose the ability to drive the shims in tightly, so that tightening the bolt doesn't distort the frame pocket.

Once you've done it, you'll know how difficult it is to pack the shims in without leaving a gap.


Good luck.