Re: Reverse shackle/ Spring over CV's

[tsm1@domain.elided (Tom Mandera)]

>	I'm intriguied by this talk of CV joints at the T-case.  Is the CV 
>like a double u-joint like on the front of Blazers or chevy trucks, or is 
>it like the front wheel drive CV joints (ball and cup setup).  Who does 

I *believe*, the two are, essentially, the same thing.. Double Cardan
(Cardon?) joints aka Constant Velocity joints.  Just two different
applications of the same thing.  On a front wheel drive, you're talking of a
slightly different application (and usually it's talked about as a unit, or
CV Half-shafts)

I'm going to guess what I'm talking about is most similar to the front drive
shaft on a Chevy truck (or Ford/Dodge/whoever else needs 'em).  Lots of
newer trucks ship with OEM CV driveshafts in the front.

Just take two U-joints and put 'em back to back, make it a single unit, and
there you have it.  Install it on the Transfer case end and you can have as
much angle coming off the t'case as you want (er.. within spec, but it can
be over 15 degrees I think).  You need to have a U-joint with "zero" degrees
on the pinion.. or 1 or 2 degrees (don't forget the pinion's temptation to
"walk" up in the back, and down in the front (it *does* go down up front,
right?)).  Anyhow.. this is usually accomplished by twisting the axle
housing.. see Jim Weed's details on grinding the knuckle welds off and
turning the knuckles to give you caster and/or change your pinion angle.

>this type of work, wo can fabricate new shafts to these specs, and how do 
>you measure the lenght of the shaft required as well as the amount of slip 
>you'd need?

Look in the back of your favorite 4x4 rag, and you'll see an advertisement
for Gloeco, Six States, or a few other driveline shops (or, again, Jim Weed
or the Binderbulletin site list off the address for Gloeco)

The ads usually explain what to measure, at least for STATIC length (vehicle
at rest, loaded)

To get a finger on your slip.. you can just say "oh.. 7" will work", or.. do
it the "hard" way.. you have to articulate your suspension while you have a
tape measure on it!

I'm planning to do something similar, since I'll also need new shocks and
I'll need to measure for those.  I was thinking of jacking the frame up and
letting the axle droop, then measure 'shaft length.  Then put another jack
under the.. driver's wheel and get a look at the twist, and after stuffing
the driver's fender, measure the driveshaft length again (assuming diff on
passenger side, per stock Scout II configuration, this means the diff will
be at it's lowest point)

After that, I'll attempt to jack the truck up by the axle tube to see how
far the whole thing stuffs.. could get creative with some ratchet straps
around the frame/axle to force it to compress some more, or you could use
the Fudge Factor rule at this point.

I end up with my static length, and a couple max/min lengths to look at, and
from there add some more fudge factor, and thus determine my static length,
where on the slip joint I should be at rest, and then how much compression
and lengthening the slip joint needs to support.

Then call up Gloeco and spend my $185 or so and have my new 'shaft
delivered..  (save my old front driveshaft to use as a spare on my other Scout!)

-Tom Mandera, Helena MT
http://www.tmcom.com/~tsm1/scout
'72 and '77 Scout IIs