Pivot Shaft Installation Woes, From Too Hard to Too Easy Options

[DennisV]

TLDR;
I attempted to install rear trailing arm pivot shafts into new bushings over the weekend and it was a disaster. First go split the bushing. Second go with bushing from alternate vendor went in by hand. I assume if it went in that easy, something is not right.

DETAIL
I started with new shafts from Restoration Design, as they seemed closest to original design (i.e., hollow). I also used their Prekom brand bushings as I was told it was the original durometer and being supplied to Porsche, Rebel Racing and Elephant Racing.

The trailing arm bushing split the top lip from the base on the first attempt to install a pivot shaft. Per conventional wisdom, I thoroughly lubricated them with dish soap, used a shop press, and had a helper.

I didn’t want to mix bushings with different specs, so I pull out all the Prekom. They seemed pretty brittle and broke apart in most cases.

Note: The dimensions (mm) of the bushing are quite different. Left to right in photos.
WDG ID: 28, Height 54
Prekom ID: 26, Height 47
Original ID: 28.5, Height 55

I wish I had measured the OD of the new pivot shaft, but didn't think to do it before installing them.




I tried again to install, this time with the same pivot shaft but using WDG bushing which I had on hand and are very close to the same dimensions of the originals. In this case I was able to install the pivot shaft into the bushings by hand. I assume it should not be that easy. (IMG:style_emoticons/default/WTF.gif)

They did appear to set up a bit after leaving them overnight, but I am able to rotate the link bearing by hand with some moderate effort. Nut torqued, but not installed on car.

So now I am left to decide if I leave it as is, or pull the pivot shaft and bushing and start over with another combination. (IMG:style_emoticons/default/confused24.gif)

[Mikey914]

We make bushings and shafts that are the same dimensions as the OEM. I do know with ours it it a tight tolerance, and is not a hand fit. It can however be tapped into place with lubrication.

[DennisV]

We make bushings and shafts that are the same dimensions as the OEM. I do know with ours it it a tight tolerance, and is not a hand fit. It can however be tapped into place with lubrication.

Hi Mike. The second set of bushings that I used, where I was able to install the shaft by hand, were from 914Rubber. Marked WDG.

Perhaps the pivot shafts from Restoration Design are not stock OD. Though if they were smaller, I wouldn't have thought my first install try would have ended like it did.