<VV> LM Rear Suspension and Diff Questions

[Mike McGowan]

Gary, the side play can be adjusted as perfect as you want it to be.  Unless 
you have Positraction, then that side has the springs and clutches as part 
of the assembly stack so there may be a little movement.

CIDCO/Otto Parts, now sold by Clark's, did a four-spider gear conversion 
that uses a center block to locate two half-shafts for the extra gears. You 
can buy this block as a separate part, Clark's C8831.  Ordinarily your side 
nuts bear against the spider gear shaft, really just a tangent on a 
cylinder, a very thin bearing edge.  You may find that both your side nuts 
and the shaft are worn and could be replaced to reduce the play slightly.

But if you add the center block, now the side nuts bear full face against 
the block and will not wear further.  Also, since the block has some slight 
thickness on top of the shaft, your play is reduced by that amount.  If you 
are lucky it will be near zero or even interfere, in which case you must 
surface-grind the nuts to measure.

For the truly fussy, Bob at CIDCO made some center blocks with no spotface, 
so thick that the side nuts do not fit.  The procedure was to grind side 
nuts to measure.  I have these parts and could do it for you, but it is a 
PITA involving test assembly, measurement, and surface grinding.  Honestly, 
you would probably be happy with the catalog part and new nuts.

When you are doing this, you might consider doing the whole 4-spider gear 
conversion.  It's costly, but you are already paying for some of the parts 
and all of the labor.

--Mike McGowan


------------------------------
>
> Message: 3
> Date: Wed, 14 Oct 2015 11:23:07 -0400
> From: edward szuch <egszuch at gmail.com>
> To: virtualvairs at corvair.org
> Subject: <VV> LM Rear Suspension and Diff Questions
> Message-ID:
> <CAA20Y4O61-Xb-KWWgTb556+PKRyiQ-pQg5PVUUp=cJp6O+LXcA at mail.gmail.com>
> Content-Type: text/plain; charset=UTF-8
>
> I'm finally getting some time to address some needed service and possible
> adjustments to my '66 Corsa.  It's a 140 with a 4 spd and posi-traction.
> It has about 67,000 miles on it.
> I removed the power train to re-seal the engine but I also wanted to
> re-pack the rear wheel bearings and will be replacing the suspension
> bushings.
> My questions are:
> 1) I want to re-pack the rear wheel bearings but I'm concerned about
> getting the bearing end play/preload reset correctly after service.  It
> looks like there is a spacer and shim(s) used to set this end play.  Do 
> the
> factory set-ups hold the correct end play after a bearing service or do I
> have to buy a number of shims to re-adjust the end play?  I'm guessing
> normal wear may increase the end play and I would have to put in a thinner
> shim.
>
> 2) I'd also like to tighten up some of the end play in the half shaft 
> yokes
> (rear suspension looseness).  The left side has .037" and the right side
> has .024".  This seems high but according to Mr R. A. Kirkman's  article 
> in
> the Tech Guide Supplement, is probably normal  for a used vehicle. 
> Looking
> at the exploded view in the shop manual, I see that a shim behind the yoke
> retaining nut might correct this but I'm not sure if it's even possible. 
> I
> know we all live with this end play but are there any tricks learned over
> the years that may improve the condition?
>
> Thanks very much!
>
> Gary Szuch
>
>