Trailing Arm Shim Setup
Thread Starter
Instructor
Joined: Nov 2019
Posts: 221
Likes: 71
From: Kalispell, MT
Trailing Arm Shim Setup
I've rebuilt the trailing arms and installed new Energy Suspension polyurethane bushings. The bushings are thicker then the factory ones I removed. The width of the shim packs on each side of the bushings is smaller then the factory ones I removed. What is a good starting point for the new shims? Should I just try to center the bushings in the frame pockets or try to get the same offset as the factory setup? I just need to get it good enough to drive it 10 miles to the alignment shop.
Last edited by C3TPI; Apr 24, 2020 at 10:46 AM.
Instructor
Joined: Aug 2009
Posts: 147
Likes: 2
From: Colorado Springs Colorado
I believe you set it up the way it was, possibly even using the original shims if you don't have enough, as that is the best starting point for alignment techs to dial it in a bit easier.
Old Pro Solo Guy
Joined: Dec 2017
Posts: 8,088
Likes: 4,446
From: Marlton NJ
These trailing arms do NOT move up and down in a straight line, they move in a rather short arc that is the length of the half-shaft. The constant rapid twisting kills the poly bushings in very short order in this position. They might work elsewhere, but they will not last long here. Sorry for the news. Bite the bullet now and put rubber in, or do it again in as little as 6 months.
Intermediate
Joined: Apr 2019
Posts: 45
Likes: 5
From: poughkeepsie ny
I bought poly rear control arms from Ecklers They lasted less than 3,000 miles before crumbling. Eckler's did nothing 'cause it was more than 1 year [ 14 months ] Bullship ! Replaced the control arms with Heim joints from Mid America . THX E
Le Mans Master
Joined: Jun 2019
Posts: 7,656
Likes: 2,469
From: Indiana
Were any failures on trailing arm energy suspension brand USA made extruded?
i read a lot of other brands failing..but wondered about energy. I used them on my struts and spring ( energy USA ones) seemed very high quality and flexible to a point.
op..manual on mine says use what came out so measure and try to duplicate. Says when aligning, shim to centerline of vehicle then fill tight the outside..
hope that helps..
i read a lot of other brands failing..but wondered about energy. I used them on my struts and spring ( energy USA ones) seemed very high quality and flexible to a point.
op..manual on mine says use what came out so measure and try to duplicate. Says when aligning, shim to centerline of vehicle then fill tight the outside..
hope that helps..
Last edited by interpon; Apr 26, 2020 at 08:53 PM.
Pro
Joined: Jun 2018
Posts: 608
Likes: 64
From: Lake Villa,IL
I was all set to get the Van Steel trailing arms with heim joints. Then I was talked out of it by the guys at Van Steel. They suggested the T/As with poly bushings. I asked about that because I've read here that thats not a good idea. They said they use a better poly that wont disintegrate under the T/As different forces. I haven't received them yet, I think I'm going to change back to my original choice but they said the heim will transfer road noise. Has anyone used poly on the T/As and not had a problem?
Melting Slicks
Joined: Jan 2000
Posts: 3,326
Likes: 523
From: home
SWAG here. Maybe someone has an arm out that can measure the distance how far the stock bushing is past the arm. Use your dimension minus their dimension and remove that much from each shim pack.
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Thread Starter
Instructor
Joined: Nov 2019
Posts: 221
Likes: 71
From: Kalispell, MT
Thanks everyone, I value your opinions one and all. 3X2: that's exactly what I did, subtract the thickness of the side plates of the bushings and shimmed tight from the outside. Should be close enough to get me to the alignment shop.
I vacillated back and forth between rubber and poly, and in the end went with the majority of suggestions from the professionals, particularly Chris Petris in his book: C3 Corvette How to Rebuild and Modify. I did choose Energy Suspension brand as they are the leader in polyurethane products and are manufactured in the US. The only regret I have is not going with the Van Steel brand that uses a swedged center tube like the factory ones. I had to tape the bushings in place to keep them from falling out while shimming, but no big deal. They're in.
I vacillated back and forth between rubber and poly, and in the end went with the majority of suggestions from the professionals, particularly Chris Petris in his book: C3 Corvette How to Rebuild and Modify. I did choose Energy Suspension brand as they are the leader in polyurethane products and are manufactured in the US. The only regret I have is not going with the Van Steel brand that uses a swedged center tube like the factory ones. I had to tape the bushings in place to keep them from falling out while shimming, but no big deal. They're in.
Had a 1976 L-82, 4-sp
Joined: Mar 2011
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From: Some days your the dog and some days your the hydrant.
Royal Canadian Navy
Nothing wrong with poly. Widely accepted in other car/truck forums except here, lol. Poly can fail but your ES ones should be ok provided you lubed them well.
Burning Brakes
Joined: Oct 2008
Posts: 955
Likes: 50
From: Jersey Shore
They are accepted almost everywhere else because there are not many suspension designs that rely on material compliance to move in TWO planes. Poly makes it more difficult for the trailing arm to move in its intended arch. Restricted movement makes for less predictable handling and faster parts wear. Poly is great for the front suspension, sway bar bushings, etc... Just not the trailing arms. Poly is an easy up-sell for vendors.
