Re: Delrin or poly...

[JustaxPHX@aol.com]

>    Have you actually done this?  It is my understanding that the a-arm
>  does not pivot around the bolt , but around the inner sleeve as the
>  vulcanized rubber twists inside the outer sleeve.

When I did this, it was on an '81 4k that used the early-style bushings
without the metal outer sleeve that was used on the later style bushings.  I
used some ultra-fancy airframe bolts that I bought cheaply at a local aero
salvage place and without a doubt, the control arms rotated around them.

> There is no metal on metal contact that I know of.  That is why the a-arm
does not just flop
>  down when deattaced from the ball joint, and why the bolts should only be
>  tightened when the suspension is at rest- to prevent a twisting pre load
>  on the bushings.

The control arms don't flop around because the bushings are slightly longer
than the opening between the mounting ears on the subframe and they have to be
pushed into place.    The bushings *definitely* rotate around the bolts -- if
you don't believe it, check the bolts for wear the next time you have
everything apart -- but given the limited amount of suspension travel
available, they don't need to rotate more than a few degrees to accomplish
this.

>  With Delrin bushings, the inner sleeve pivots inside a
>  loose tolerance hole through the Delrin...

Beats me ... I've never seen any bushings other than those I had made from
Turcite and they were definitely made with very tight tolerances.

JG