Date: Mon, 27 Jan 2003 09:39:58 -0800
Reply-To: Tom Young <tomyoung1@ATTBI.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Tom Young <tomyoung1@ATTBI.COM>
Subject: Re: CV article now available - I'm confused (long)
Content-Type: text/plain; charset="iso-8859-1"
I'm confused about the issue of reversing the direction of rotation of the
axles to extend the life of the CV. In the article it states:
-------------------------------------------------------
"Assume you're looking at the back of the van,
and the CVs are labeled with letters, like this:
A------B Transmission C------D
You can move the axles so that the letters now read:
C------D Transmission A------B (option 1) OR
D------C Transmission B------A (option 2)
These two configurations will result in the CVs being
reversed. Note, however, that the following
configuration will NOT reverse the CV joint rotation:
B------A Transmission D------C
IN OTHER WORDS, IF YOU MOVE THE AXLES TO
THE OTHER SIDE OF THE VAN, THE ROTATION
WILL BE REVERSED."
(emphasis added)
-------------------------------------------------------
I grabbed the cardboard tube inside a roll of toilet paper and labeled the
left side "C" and the right side "D" and then drew arrows above the letters
pointing away from me:
^ ^
| |
C D
This shows the direction of rotation of the axle on the right side of the
van in the first diagram.
If I move the roll to the left side, as in option 1, it ends up looking
exactly the same:
^ ^
| |
C D
so the statement "In other words, if you move the axles to the other side of
the van, the rotation will be reversed" does not seem to be literally true.
Option 2 orientation, however, results in the arrows pointing toward me
("down" on this page) as:
D C
| |
v v
(The D and C should be upside down and backwards, but you get the idea.)
Which *does* reverse the rotation of the axle.
And the last diagram - the orientation of axles on the same sides as they
were, only flipped end-for-end, looks exactly the same as Option 2"
D C
| |
v v
which, again, has the direction of the axle's rotation reversed from what it
was.
So it looks to me that if the object of the exercise is to reverse the
*rotation* of the axle then Option 2 should work as should flipping axles
end-for-end.
Thinking that the term "rotation of the axle" wasn't the term the author
really intended to use, I redid my cardboard tube as follows:
^
|
C D
|
v
which reflects the pressure the joints on the right-hand axle "feel" under
driving load, i.e., the C joint has the torque of the transmission urging it
"forward" while the D joint is overcoming the inertia of the vehicle.
The Option 1 orientation looks like
^
|
C D
|
v
ญญญ
that is, the D joint is now being urged forward while the C joint is
resisting, a change from the original orientation.
But Option 2 looks like
^
|
D C
|
v
resulting in *no* change from the original orientation.
And the final diagram in the article would likewise look like:
^
|
D C
|
v
resulting in *no* change in pressures from the original orientation.
I'm going to assume that the author is correct and that simply flipping the
axles end-for-end on the same side of the transmission as they were
originally is *not* accomplishing anything since I've read this sort of
remark in various places. However, looking back through the diagrams I've
constructed, that says the *only* orientation that works is Option 1, that
is:
C------D Transmission A------B.
Am I smoking my socks here folks?
---------------------------------------------------------------
Tom Young '81 Vanagon
Lafayette, CA 94549 '82 Westfalia
---------------------------------------------------------------
----- Original Message -----
From: "Ben McCafferty" <ben@VOLKSCAFE.COM>
To: <vanagon@GERRY.VANAGON.COM>
Sent: Monday, January 27, 2003 6:44 AM
Subject: CV article now available
> Good morning everyone,
> My first tech article is now available on the Volks Cafe website, covering
> CV joint diagnosis, maintenance and replacement. From the home page, look
> for it under "New Items", or use this link:
> http://volkscafe.com/articles/cvarticle/cvarticle.html.
>
> It is quite lengthy and detailed, and I'd love any and all feedback. The
> next article, which covers oil pressure diagnosis and treatment as well as
> OP gauge installation, will be out later this week.