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2020 Corvette of the Year Finalist (performance mods)
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trailing arm shims in incorrectly
So , I had my rear wheels off while I was bleeding my rear brakes and noticed my rear trailing arm shims sticking out. I guess the B.O. (bubba owner), had put the bolt through the hole and obviously couldn't use the cotter pin. They can't fall out this way but I need to remove the bolt and put them in correctly. Is this a major pain in the butt to do? And will I screw up the alignment trying to get them in correctly. I've put a couple hundred miles on the car like this before noticing it and it isn't currently affecting anything. I'll try to get pictures shortly, Its in semi storage until the garage is freed up at the end of the month.
Hi RR,
The alignment shouldn't become an issue if you keep track (measure, count, photos) of the current shims and get them back in the same location.
Getting the bolt out might be difficult depending how long it's been in there.
Remember, with the spring still bolted to the other end of the t-arm the t-arm is going to want to move when you remove the bolt.
Regards,
Alan
For what its worth, depending on the year, the shims are U shaped at the upper end where the bolt holds them in. I believe the shims can be tweeked by just loosening the bolt. The C2 shims are not U shaped and do not have the hole for the cotter pin, IF that's what the PO used.
If you get replacements, I would go for the stainless steel
Last edited by mikem350; Dec 15, 2015 at 04:23 PM.
If you have a 68 or 69 the shims have a hole and sets inside the pocket and does not use a cotter pin. Starting in 70 they started using a slotted shim and the shims were longer and the cotter pin that goes through the frame in the hole of the shim and then out the other side of the frame. This is from memory I hope somebody can verify this.
2020 Corvette of the Year Finalist (performance mods)
2019 C3 of Year Winner (performance mods)
2016 C3 of Year Finalist
Does anyone have pics of the early 68 shims. Mine was built in oct 67. I seem to remember seeing the horseshoe side on the inside of the arm with the tire off but when I looked today I found the round hole on the outside of the arm.
Does anyone have pics of the early 68 shims. Mine was built in oct 67. I seem to remember seeing the horseshoe side on the inside of the arm with the tire off but when I looked today I found the round hole on the outside of the arm.
That looks like the correct way except the hole of the shim you are showing should be in the frame pocket and not parallel to the trailing arm.
Hi rr,
Your Oct 67 car's frame wouldn't have originally had the holes in the frame for the cotter key used with the slotted shims.
Here you can see the position of the loop end of the cotter key and how far into the frame pocket the shims must be inserted to let the key pass through the holes.
The hole in the frame must be that low in order for the key to pass below the t-arm under full suspension travel.
Regards,
Alan
Remember this is a late 69+ frame, cotter key and shims.
2020 Corvette of the Year Finalist (performance mods)
2019 C3 of Year Winner (performance mods)
2016 C3 of Year Finalist
Originally Posted by 69FASTFUN
If you have a 68 or 69 the shims have a hole and sets inside the pocket and does not use a cotter pin. Starting in 70 they started using a slotted shim and the shims were longer and the cotter pin that goes through the frame in the hole of the shim and then out the other side of the frame. This is from memory I hope somebody can verify this.
The AIM doesnt show anything specific and the catalogues don't show anythng other than the slotted type for 68-82. Im going to search online to see if theres anything different.
Is there a way to verify the alignment without bringing it to a shop? The AIM doesn't really give a good description of the procedure. How does it lock in to the arm? The AIM doesnt show that either.
Thanks
2020 Corvette of the Year Finalist (performance mods)
2019 C3 of Year Winner (performance mods)
2016 C3 of Year Finalist
Thanks. Is there a picture of the frame pocket? Im not really following how that works. You guys post quick. I was writing and when I finished the last 2 posts were up
Well assuming you slide the U shaped part of the shim under the long bolt and push the bottom of the shim with the hole into the pocket and then tighten the bolt the shim really can't drop out because the bottom of it will be sitting on the pocket frame. Make sense? I will see if I have a picture.
Oh just to get a real rough alignment you can put a level up and down on the rear tire while on a jack with no weight. Then you can adjust it accordingly.
Oh just to get a real rough alignment you can put a level up and down on the rear tire while on a jack with no weight. Then you can adjust it accordingly.
This will set the camber, which is changed via the tie rods.
Playing with the shims will change the TOE. You already have a rough alignment, just keep the same shim placement as Alan has said.
I'm a little strange....once I have it where I want it...I install the shims "backwards" and put the bolt through them. Yep...takes a little work...but they never fall out!
Hi RR,
You really don't want to use the slotted shim without the cotter key.
While you certainly can install them with their rear edged dropped below the opening in the trailing arm pocket in the frame, they MAY, over time, move up as the car is driven and the suspension cycles.
Once they move UP they MAY also move BACK and then fall out. This is the precise reason for the cotter key.
Pretty straight forward:
Shim with no slot… bolt goes through the hole, shim can't fall out but bolt must come out for toe-in realignment.
Shim with slot: shim slides on to bolt, cotter key holds it in place, easier to do toe-in alignment.
Regards,
Alan
PS That's the current floor in my garage…. my restoring days are over so the car gets to sit on a nice floor.
trailing arm shims in incorrectly
