View Full Version : Polyurathane question

09-04-2005, 01:00 PM
Hey all! A question about which poly to pick for leafspring suspension bushings and motor mount bushings.
I was given a link to Redwood plastics and found what I want but am not sure what hardness to order.
It comes in hardness or "durometer values of 52A,54A,62A,70A or 80A.
Any ideas what I should pick? Thanks!

09-04-2005, 01:04 PM
Hi Russ,

Take a look at the plastic springs on the McMaster-Carr website http://www.mcmaster.com

They have a good explanation of the different types of plastics and their applications.

09-04-2005, 02:09 PM
It really depends on what kind of use the vehicle is going to see. The very hard ones have a very limited lifespan and are hard on the other parts of the suspension. (and you too). I have had them on the P/U. Took them off as they did not help with towing sway but did make the truck noisier and harsher on the ride.As an aside, I use to run a A/class Dodge dart and I put machined aluminum in that to eliminate twist and wrapup.

09-04-2005, 02:12 PM
I would seriously consider OEM type bushings for suspension parts. Poly can be really rough, almost as bad a "hard" points or spherical bearings.

For the motor and tranny mounts poly helps control engine toque over and lasts longer than rubber in the harsh environment. I think my motor and tranny mounts are a 60 hardness. JRouche

PS: Seems polygraphite is the hot ticket these days, self lubricating. That was always the problem with poly, you had to always lube them. So on a street car it usually never got done. On a race car its just part of the maintenance. On a four link I had I installed zerks just for this purpose, works OK.


[This message has been edited by JRouche (edited 09-04-2005).]

09-04-2005, 03:31 PM
Thanks guys! Forgot to say...this is for a 4X4 Toyota pickup I'm building.
It'll be getting a 4.3/700R comdo in it soon. I need the poly to make some motor/tranny mounts.
For the leaf springs...I'm setting this up to do a bit of playing in the rocks so it has to have lots of flex. Made up new front leaf packs from 3 sets of Toy rear springs and have a set of long flexy Chevy 1/2ton springs in the rear. Guys who do this tell me that stock rubber bushings sqwish out in a short time and that poly is the way to go.
I have lots of UHMW but it's too hard for either bushing set.
I can buy all of this but it's around $150 for both sets (Toyota and Chevy). I have to buy both sets to get the bushings for both packs. I'd only use half of the bushings supplied in the kits. I'm betting for about $30 I can build the whole works.
Thanks again!