40 Rear Shackles in Polyurethane

Nylon is stiffer then Polyurethane.....poly comes in different grades of tough...but still flexible.
For this aplication it might work just fine...
Another downside with nylon is that it absorbs water...
 
Yep rubber absorbs water to.
Poly is superior if you want something flexible like a swaybar bushing.
But in this aplication the stiffer nylon may work just fine....
 
Nylon is a better bearing material for a rotational bearing...
Squeeks usually comes from binding and releasing...
I would give the nylon a chance if they hold up for the impact force and not deform they may be just fine.
 
I've never had the street rod type bushings that didn't squeak or creak. I've converted to flanged bearings from a bearing house. They are oil impregnated bronze and don't squeak. I get mine at Motion Industries.
 

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Poly will tend to squeek sooner than Nylon or Delrin unless you keep lots of grease in them.
I have been making bushings from moly filled Delrin since Biblical times and most are still in service.
 
As Pete said, Delrin is the material of choice for that application. And as Mike K will likely chime in, the original shackle bushings were press fit, and part of the suspension design. You are taking away part of that design with none original shackle bushings. I bought a cheap ball joint press at HF, and made my own adaptors for it just the like KR Wilson tool. I can press old bushings out, and original new ones in with the rig.
 
russcc said:
As Pete said, Delrin is the material of choice for that application. And as Mike K will likely chime in, the original shackle bushings were press fit, and part of the suspension design. You are taking away part of that design with none original shackle bushings. I bought a cheap ball joint press at HF, and made my own adaptors for it just the like KR Wilson tool. I can press old bushings out, and original new ones in with the rig.
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The problem is the replacements are too big. I tried to press an original in and it just mushroomed at the top, even after reaming the hole. No other vehicle these days uses such a press in bushing. Even my 8 ton bus uses polyurethane bushings. Also they can rotate which is a big advantage over stock.
 
john in illinois said:
It is welded on the outside. You would have to watch out for warpage.Clamp pins so they can not move.

John
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I just tacked them first then ran a bead. They will never come loose. After allot of research, I decided to run nylon bushings. Another important step is to order Formula 5 grease from Energy Suspension. Energy claims that if you use their grease, squeaking is no longer an issue. I really don't like the stock rubber ones because as the spring rotates, the rubber is torn from the inner and outer sleeves. Nylons will hold up better and no squeeking with Energy's special thick, waterproof grease. Watch their video, very convincing.
 
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