Date:         Tue, 2 Jun 2015 13:29:26 -0400
Reply-To:     Ed McLean <email99@BELLSOUTH.NET>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         Ed McLean <email99@BELLSOUTH.NET>
Subject:      Re: Rear axle torque specs?
Content-Type: text/plain; charset=ISO-8859-1

Phil z,

Thanks for your reply.

My confusion is why there is so much incorrect information about the
design of the rear wheel bearings.

I apologize for sounding condescending and for excessive use of some
specific words.  That was not my intention.

My use of the term "pre-load" is force that is exerted by the axle nut
on inner race through the rotating elements of a bearing, that is the
balls or the rollers, to the outer race of the bearing.  This is not the
case in the Vanagon rear hub.  In the Vanagon rear hub the force exerted
by the axle nut locks the axle, the inner races of both bearings, the
spacer, and the hub together.  There is no force from the axle nut
exerted on the balls or the rollers of the two bearings, hence, no "pre-
load".

If you jack up the rear wheel of a Vanagon you will notice there is a
small amount of play if you grab the wheel at 3 and 9 and shake.  If
there was bearing "pre-load" by an axle nut torqued to 369 lb-ft there
would be no play.  If you do the same thing on the front wheel of a 2WD
Vanagon you will also probably feel a small amount of play.  However, if
you remove the grease cap and "pre-load" the bearings by torquing the
front axle nut to 15 lb-ft you will see that the play has gone away.
The difference is the front wheel bearings are tapered roller bearings
that can be pre-loaded and the rear wheel bearings are roller and ball
bearings that can't.


It has been a while since I've had a rear bearing apart but one thing
that comes to mind that could cause problems is that maybe the inner
ball bearing is not fully seated in the housing.  I don't know if this
is possible with the snap ring but maybe the snap ring is not in place.
If the bearing is not fully seated then the inner race of the roller
bearing would not be precisely located under with outer race and the
ends of the rollers would be rubbing the ridges on the races that should
keep them in place.  If you pull off the hub you might be able to see
some scoring on the ends of the rollers.

Also, when replacing the axle nut, the hub should turn just as easy when
the nut is finger tight as it does when fully torqued.  This is
different than with pre-loaded tapered roller bearings in traditional
front wheel bearings.


I hope this helps.  Thanks again for your reply.

Ed



On Tue, 2 Jun 2015 09:21:48 -0700, Phil Zimmerman <philzimm1@SHAW.CA>
wrote:

>Date:         Tue, 2 Jun 2015 00:44:53 -0400
>Reply-To:     Ed McLean <email99@BELLSOUTH.NET>
>
>Ed typed:
>
>I'm a bit confused by this thread.  Some one tell me if this is not a
>correct description of the assembly.
>-----big snip for brevity----
>
>I hope this helps.
>Ed,
>--------------------
>
>Ed,
>
>I do't believe or feel you are one bit confused by this thread and your
description is pdc (pretty darn clear).IMHO
>
>What does stand out to this reader is your dislike of the word "pre-
load" when describing bearings in the rear end of a Vanagon.
>Which is fair, as the bearings in the rear are not tapered like in the
front of the Van.
>What one calls the squish that holds the things together is rather a
moot point now.
>A guy with a Vanagon has way-too-hot bearings and is looking for some
help.
>
>Ed's use of the word "simply", multiple times, seems or sounds
condescending? Which I ponder if he means this to be-so
>or is he attempting to simplify our understanding of the rear wheel
bearings used in a Vanagon?
>The Re/Re of rear wheel bearings can be a daunting task for many of us
on this list. For a seasoned mechanic or Journeyman/girl, a walk in
>the park. I do not know where Ed fits into this continuum? But, I am
assured through his writing, he is not confused.
>
>When the rear axle nut is torqued to spec and all parts from the hub
and stub-axle through the wheel-bearing-housing
>and internal bearing parts are put under this considerable load… if
this aint a pre-load; I dunno Ed, 360 ft lbs is sure
>more than sung and significantly greater than finger-tight? (excuse my
sarcasm and hyperbole) I would prefer to use
>a few choice swear-words here but, the Vanagon nannies forbid such
language.  Forgive my digression here.
>
>Back to deducing or ferreting out a meaning from Ed's confusion..
>What was the question again Ed?
>
>Thank-you for your clear and concise contribution to this thread Ed.
>I'm assured the OP will find this information helpful when dealing with
the mechanics at the Shop he hired to remedy the bearing
>problem(s).
>
>On his rock off the West Coast
>
>Phil Z.