PVC trailing arm bushings?

For road racing, autocrossing, or just taking that curve in style. Oh yea, and stopping!
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FJCamper
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PVC trailing arm bushings?

Post by FJCamper » Sat Nov 04, 2017 2:07 pm

Image
Above: The red bushing is circa 2004, the black new out of the blister pack. Both are Prothane brand. Lube is black moly grease.

PCV Pipe Trailing Arm Bushings

We have a RetroRacing team driver/mechanic (David Scott) who is a real MacGyver at rustic but effective track repairs.

When we finally had a Prothane urethane trailing arm bushing (lower right in this case) fail in our 1969 Historic Sportscar Racing Ghia late one night, and no replacements were available and we had to be at Sebring the next day, David searched through the shop and found some PVC pipe, and some very thin sheet metal (think beer can) to use as a circular shim inside the PVC.

The lower trailing arms are different from the tops in that the lower has a stepped shaft, and the upper shaft is straight. Some trailing arm bushing kits are sold as four single bushings, and some are sold as with the lower bushings as two pieces, a stout outer bushing and a sleeve for the inside. We had the two piece lowers.

David fabricated our repair in December 2015. We'd been meaning to formally repair it before every race, but it just kept working. Next week we'll be at Daytona for some very fast laps in the Classic 24, so we finally pulled the trailing arm and the photo above reveals what we found.

The innermost end of David's sleeve had separated because of the stress from the trailing arm there, but otherwise we still had a working system. Barret Camper, lead driver, said he could feel the separation.

We don't advocate PVC pipe bushings, but it's good to know there might be a save for you just in case.

FJC

Bruce2
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Re: PVC trailing arm bushings?

Post by Bruce2 » Sun Nov 05, 2017 3:24 am

Delrin would work.

Then again, so would stock roller bearings.

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FJCamper
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Re: PVC trailing arm bushings?

Post by FJCamper » Sun Nov 05, 2017 11:12 am

On the night before the race we had no access to more urethane or stock parts.

I read many guys prefer Derlin.

For our purpose, road racing, a stock bearing would work just fine.

I understand these urethane trailing arm bushings were originally targeted for the off-road crowd, who had sometimes crushed the factory bearings. I hoped for more support along the entire length of the trailing arm shaft, and gave the urethanes a chance.

All my accumulated experience tells me I would have been as well off with the stock system

FJC

PhillipM
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Re: PVC trailing arm bushings?

Post by PhillipM » Fri Nov 10, 2017 11:15 am

I run delrin, a lot better in terms of consistant friction vs urethane.

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