Another trailing arm bushing question, Polly bronze durable? Options

[trojanhorsepower]

I relatively recently installed my new set of 914rubber bushings. These were purchased maybe 10 years ago and installed maybe 5 years ago, but since the car was apart they have almost no miles on them. After finally being able to drive the car I found this.

https://www.youtube.com/shorts/2DWFetQ51aE
https://www.youtube.com/shorts/H5XFSS_rh74

So clearly these don't fit properly. I was going to go with the Elephant racing kit, but a friend of mine installed poly bronze bushings on his Jeep and they did not last a year. Anyone have any experience with these bushings as to long term durability? Or should I just bite the bullet and go with the soft rubber original style?

Thanks,

Peter

[Montreal914]

Bruce Stone installed a set of Prekom rubber stock (or sport (IMG:style_emoticons/default/idea.gif) ) in my arm. They were a pain to install as they should. On Prekom's list page when hovering, the description says designed and made in the US. But when you click on the description, it states these were designed and are fabricated in EU per original specifications. I belive it is the latter.

https://www.prekom-usa.com/product/porsche-...bushings-stock/

There was a thought these could be the same as the ones sold by ER in this kit below. They are also sold by Restoration Design EU.

https://www.elephantracing.com/porsche/914/...for-914/rubber/

Time will tell if they last.


Having purchased a set of Rebel Racing front (RSR) bushings, I have been wondering how their matching rear kit is. (IMG:style_emoticons/default/idea.gif)

This: https://www.rsrproducts.com/product-page/re...ear-bushing-set

After talking with @bdstone914 who has restored many trailing arms, one of the issue with any of the rigid options comes with the fact that the cylindricity of the trailing arm's tube is deformed probably due to its welded fabrication process.

ER's polybronze bushings compliance of the red part compensates for this problem, then you have a classic bronze over steel pivot design.

[bdstone914]

Bruce Stone installed a set of Prekom rubber stock (or sport (IMG:style_emoticons/default/idea.gif) ) in my arm. They were a pain to install as they should. On Prekom's list page when hovering, the description says designed and made in the US. But when you click on the description, it states these were designed and are fabricated in EU per original specifications. I belive it is the latter.

https://www.prekom-usa.com/product/porsche-...bushings-stock/

There was a thought these could be the same as the ones sold by ER in this kit below. They are also sold by Restoration Design EU.

https://www.elephantracing.com/porsche/914/...for-914/rubber/

Time will tell if they last.


Having purchased a set of Rebel Racing front (RSR) bushings, I have been wondering how their matching rear kit is. (IMG:style_emoticons/default/idea.gif)

This: https://www.rsrproducts.com/product-page/re...ear-bushing-set

After talking with @bdstone914 who has restored many trailing arms, one of the issue with any of the rigid options comes with the fact that the cylindricity of the trailing arm's tube is deformed probably due to its welded fabrication process.

ER's polybronze bushings compliance of the red part compensates for this problem, then you have a classic bronze over steel pivot design.

There are several reasons why rubber bushings are a better choice over hard material ones like 914 rubber makes. The rubber adds dampening as is grips the shaft.
Almost all shaft are bent. I have torn down over 20 pairs only to find a couple pair that are not bent. This makes hard bushings more difficult to install. The trailing are also not consistently round and the bushing ends not in line. This is from the forces of cornering.
The holes can be oversized. I had a pair of the 914 rubber bushing and they fit loose.
The Prekor bushing are very difficult to install. I have done four sets abd it takes about 4 hours. I had to make tools to install them. I ripped three bushing out of four sets installing them carefully. The design is flawed. It has an undercut below the flange where it should be thicker. The flange can tear off. They have no instructions or do they know how to install them. I have had several conversations with Igor at Prekom about improving the design. I don't know if they improved them.
ER buys Prekor and marks them way up
They at least sell the tools with them.
I am not addressing poly bronze bushings as I have not used them.
That my story and I'm sticking too it.