Anyone seen this happen to a C2 trailing arm bushing

[Donald H.]

The pictures are of a trailing arm we took off today. This is a friends car. It is a 67 435 HP convertible. Yes its a real 67 big block that he has owned since 1981.

The trailing arms have less than 1000 miles on them. They are offset arms he bought from Year One, but when we looked at the arms, they have writing on them from Van Steel, so we assume they were assembled by Van Steel and just sold by Year One.
I think these were polyurethane bushing and they have simply crumbled. One of the picture show a pile of the bushing that I dug out of the frame pocket.

Yes, all the alignment shims were still in place and the bushings were tight side to side in the frame pocket.

Anyone seen this happen and what could cause it?

We reinstalled rubber bushing and put the arms back on the car today.

Note: I also posted this same thread on the Corvette Forum just to see if anyone over there has seen this, and what could cause it.

Thanks,
Don

[David H.]

Re: Anyone seen this happen to a C2 trailing arm ushing

Donald,

Curious, any other rear suspension changes to this car? (Coilovers, composite spring, etc.)

Can’t tell from the photos - cushion crumbled? or fractured? Crumbled-small jumbled pieces or fractured-having smooth breaks (like how old jello in the refrigerator splits apart). Reason I ask, have had aftermarket C4 front spring cushions fracture when they fell 3 feet off a table.

Dave

[Donald H.]

Re: Anyone seen this happen to a C2 trailing arm ushing

The bushings seemed to have crumbled to me.

Yes, he has other mods to the car. Larger rear sway bar, adjustable strut rods, and the fiberglass monospring.

[Duke W.]

Re: Anyone seen this happen to a C2 trailing arm ushing

As the trailing arms go through their suspension travel, they twist because of the camber change. The OE rubber bushings are designed to accommodate this. Any type of replacement solid bushing must be spherical to accommodate the twist, like a spherical heim joint. If these bushings are cylindrical they are a recipe for failure and were designed by someone who is totally clueless about the requirements for this joint.

It never ceases to amaze me the amount of junk sold by the aftermarket.

Duke

[Michael W.]

Re: Anyone seen this happen to a C2 trailing arm ushing

Poly bushings are meant to rotate freely on their mounts, unlike OEM type which must be trapped tightly. No surprise that they failed.

[Joe L.]

Re: Anyone seen this happen to a C2 trailing arm ushing

All------


I wouldn't touch off-set trailing arms or poly bushings with a 10 foot pole.

[Brian M.]

Re: Anyone seen this happen to a C2 trailing arm ushing

May I ask Joe, why that is ? I'm getting to a point in a rebuild and I'm considering Poly Vs Rubber. Actually thought about offset arms. Thoughts ?
Thanks

[Joe L.]

Re: Anyone seen this happen to a C2 trailing arm ushing

May I ask Joe, why that is ? I'm getting to a point in a rebuild and I'm considering Poly Vs Rubber. Actually thought about offset arms. Thoughts ?
Thanks

Brian------


Using polyurethane bushings and off-set trailing arms amounts to re-engineering the chassis and suspension. GM spent MILLIONS to properly engineer the chassis and suspension. Trying to re-engineer it is fraught with problems. There are tweaks that can be effectively made but not a "wholesale re-engineering".

Polyurethane bushings are not used in any factory installation I know of, including high-end exotics. Ever wonder why?

Look at the experience of the original poster here. What more needs to be said?

[Donald H.]

Re: Anyone seen this happen to a C2 trailing arm ushing

After working on my friends car and seeing what happened, Not sure why anyone would consider poly bushing on a trailing arm.

Don

[Brian M.]

Re: Anyone seen this happen to a C2 trailing arm ushing

Got it . Thanks Joe.

[Bruce D.]

Re: Anyone seen this happen to a C2 trailing arm ushing

I have seen and helped many friends with this problem. Poly bushings, especially trailing arm bushings will fail with very little age or miles. I almost wrote an article for the Restorer but was afraid it would not get published because so many of our advertisers make them available for sale. I have not seen this with rubber replacements.