More than 50% of the trailing arm pivot shafts we remove look like this:
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After sanding on the belt grinder it is down to the original diameter again:
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but, after wire brushing, the deep pits that remain are evident. Installing this shaft into any plastic bushing can't be good for longevity:
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I was having the best shafts that I could find centerless ground for a while to true them up without removing too much material. What I found was that the shafts aren't straight enough to true them with removal of only 2 thou diameter, and if there are any pits the .002 removed doesn't get rid of them.
So I designed new shafts that are more precise and stronger than the originals:
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Our delrin bushings have a light press fit into the trailing arms. This means the id is no longer the correct dia or round any more so we ream them precisely using our "home-made" tools. The trailing arm bores also aren't quite straight relative to each other. Reaming or honing each one independently means they aren't going to be concentric. The id has to fit more loosely in order that the shaft doesn't bind when inserted through both ends.

This method is hardly precise, lol:
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The long shaft added to our reamer allows it to align from the bushing at the other end, thereby ensuring concentricity of the two bores.
The modified pivot shaft holding the lathe tool bit is used to cut the end of the delrin bushings precisely. This ensures that the pivot shaft will be about .005" longer than the bushing end to end dimension so no side play or binding is evident after installation in the chassis.
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dat dare is preety schwanky my man!

Yeah I'm with you here. I'll put away my caliper and start saving. After looking at Chris' setup it's not worth re-inventing the wheel, so to speak. I'm not into mass production. That's about the only way you could recoup tooling costs.

Perhaps someone has cut open a pivot shaft, but a couple of years ago I x-rayed one out of curiosity (didn't want to destroy it). It is a simple tube with machined segments welded on each end. Nothing particularly tehnical about them.

I agree that Chris' method assures proper axial alignment of the two bushings; otherwise it's only a best guess.

Andys

I purchased some bushings a while back about a year ago off ebay for the front and rear all i remember is them being black is there any way to tell weather they are delron 94a or 70d how can i tell?

Thanks

How much did you pay?

Here's the real determining factor; squeeze them. If you can distort them with your hand, they are "not" Delrin or 70D. If they do not bend or flex consider yourself lucky. They will have to be either machined or honed to fit but that's a good thing.

I know this started as a rear bushing thread but this is what I have researched on the fronts.

Are weltmeister considered hard or soft? I have a front set already installed with zerts in the housings and they seem pretty hard. I don't think they are as hard as delrin but they seem hard enough.

For the front the housings seem to be 2.0 id x 2.0 wide and the a-arm shaft od seems to be slightly less than 1.5 which might be a problem without making a sleeve to repair or size the part the bushings go on, to 1.5.
These bronze bushings for the front I found at McMaster Carr seem to be the right size: 7965k58 1.5ID x 2.0 OD 2.0 inches long 25.13, If you want 2.5 long and cut them to exact length go with, 7965k57 27.60, or get a 4.0 long one and cut it in half 37.29,
Theres a bronze thrust thats 2.5 od flange, 1.5 id,x .125 thick. 7814k39 5.30.
If I were to go this route I think I could sand the od down and put them in with jb weld into the housings and add the zerks.

It's at least 95.00 for the bronze parts and thats not counting a a-arm shaft sleeve x 4 if it's needed.

I read the install on one of the sites and they use jb weld to install the inner sleeves on their shafts.

I think the rear might be done the same way with putting sleeves on the shaft ends and making them smaller than the sleeves and using jb weld to center them in the bushings, or using jb weld to locate the bushings in the rear control arms.

I am also running the linear bearings from the original designer/manufacturer, Shine racing www.srsvw.com
I am still quite happy with them.

Rich

Click to view attachmentSo this is a picture of the bushing i purchased over a year ago, what do you think are they the soft or hard bushings. This was the most i could bend it before eating my spinach either way it might pay to get the ones PMB are selling for $20.

Thanks
Matt

Pretty obvious.

That's a perfect example of a softie.

I just ordered a set of hard bushings from your place do you have the front set?

3-4 years now...still swing like butter.

Rich

Swing is a foregone conclusion, but is there any slop....lateral or axial.
My needles are still tight but wear was evident on the thrust washers.
I turned them over.

BTW, Rich, I had the tranny down & found a broken needle bearing cage under first gear. The needle was still in place but the cage was cracked thru side to side. That coulda got ugly.

No fronts sorry.