Date:         Thu, 27 Jan 2005 09:20:51 EST
Reply-To:     THX0001@AOL.COM
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         George Goff <THX0001@AOL.COM>
Subject:      Re: Power Steering  Boots and Back-up Wrenches
Content-Type: text/plain; charset="US-ASCII"

In a message dated 1/27/05 12:05:42 AM, jeff@VANAGONPARTS.COM writes:

<< You need to use two wrenches to remove the tie rod from the from the rack,
one wrench on the tie rod, the other is used on the rack shaft to prevent it
from turning in the rack housing.  Use a little loc-tite when you reinstall
the tie rod and tighten it a little past it's previous position (with two
wrenches again) and tap the lock ring into place. >>

I'm hardly a stranger to using a back-up wrench whenever there's a need for
one.  And, the first time I renewed Vanagon tie rods I considered doing just
that, complete with wrenching on the rack (the rack is the toothed shaft which
slides within the rack and pinion housing) hard enough to shear off the locking
tang.  I reconsidered this dodge and, for good reason, I decided to remove
the rack and pinion assembly to do the work at the bench.

A back-up wrench used in this manner has to do a little more than just
prevent the rack from turning.  To be able to say veraciously that no harm is done
to the rack and pinion assembly while using a back-up wrench on the rack would
take the certainty that equal and opposite forces are applied to both wrenches
precisely about the center of the rack and that these forces are removed at
the instant the tie rod loosens.  It takes a fair amount of break-away torque
just to unseat a tie rod.  Add this torque to the amount of force required to
shear the locking element and the total torque becomes considerable.  Using a
back-up wrench on the rack is no assurance that the assembly will not suffer
unnatural loading, especially at the moment the tie rod yields it's grasp to
this balancing act.

Then there's the back-up wrench itself which should have soft jaws.  So, you
are left to try to find one to fit the rack, to roll you're own or to risk
damaging the rack with a regular wrench.

Now, if the suggested scheme is followed, the tie rod is screwed back on the
rack and rotated past its original position.  Here's a question for the
resident MechEng types: how much torque does it take to rotate a drawn metal tie rod
ball joint cup onto a thread of about 25 mm in diameter an 1/8" past its
fully torqued position?  Balance this force exactly against a back-up wrench?  No
mean feat, that.

What makes this approach to replacing steering rack boots puzzling is that
neither the tie rods nor the outer tie rod ends have to be removed on many
(most?) vans.  A lot of Vanagon tie rods have a rubber collar on which the outer
end of the boot fits.  Even the smaller diameter of this style of boot will fit
over the tie rod end once it is undone from the steering knuckle, preserving
the alignment.  Of course, a tie rod end press is needed because a pickle fork
will almost certainly bitch the tie rod end boot.  The other style of boot,
with a small end that fits directly on the tie rod diameter, can ONLY be
replaced by removing the outer tie rod end from the tie rod.  Perhaps I shouldn't say
"only"; who knows, a fresh boot might be like other things which will stretch
a mile before they tear an inch.

George