Two comments about the C4 Technical FAQ and Summary

1) It appears to have become unstuck and no longer appears
at the top of the C4 Tech forum.

2) The section on u-joints needs some expansion. An entry
that reads

"The best u-joints are the Spicer units."

simply misses the mark.

Perhaps consider adding something based on a post of CFI-EFI's,

Required "are 1310 series, part number 5-786X, for the drive
shaft (2 ea.). And 1350 series, 5-800X, for the half
shafts (4 per car). There has been some superseding that
has taken place, but those are/were the part numbers for
the non-greaseable anti-galvanic (coated caps) u joints
recommended for the aluminum shafts."

Bonus points for mentioning that the correct joints have
a special dielectric coating to delay/prevent galvanic
corrosion which is prone to occuring between dissimilar
metals.

Maybe add a notation that the 5-785X & 5-799X versions
of these parts are intended for use with non-aluminum shafts
and thus do not have the special coating.

DIY'ers might appreciate a link to a pictorial guide about
how to change joints, such as the one scorp created some
time ago. Amended of course, with CFI-EFI's tip about
saving the trouble of loosening the camber adjusters
by removing the outer ends, instead.

Of course including known vendors and pricing would be
sure to count towards the eventual attainment of Sainthood

.

Here is Spicer's list of Common U-Joint Kits by Series

From the Literature Section of Dana's website.

.

BTW, my new opinion of the Spicer joints, is they are flawed. They have hard plastic seals and these are easy to crack during install, and even if they don't, they can crack while on the car.

I pulled my driveshaft out and two of them were missing pieces of the plastic seal, which I guess exposes the lube to dirt.

Specifically, this was the 5-786X parts. I didn't check the halfshaft ones.

Yes, I remember reading that one/some of the plastic seals
broke on you during installation. I think your assessment
at the time was that possibly the spider was pressed too
far. Still, it would not have been an issue with 'rubber'
seals.

Now it appears that there have been additional failures
while in service.

.

BTW, C4boy created a post called 'Half-shaft U-Joints:
Everything You Always Wanted To Know'

In it he mentions

3-70-48X – (update) This is the strap kit part # for the
axle shaft u-joints. You get 2 straps and 4 bolts in a kit
and the cost should be around $10 or less. The bolts are
metric. The thread diameter of the strap bolt is 8mm x 1.0
pitch. The bolt is 19.05 mm long, Grade 8 steel. Strap bolt
holes are 1.806" center to center. C4 axle u-joint strap
bolts are NOT american thread.

It would be useful to confirm this and add the companion
strap kit # for the driveshaft u-joints

Also, mention should be made of GM's practice (from FSM)
of marking the orientation of the shaft to the yoke

From the prop shaft section in my manual for an '89, the
manual states that there is a black spot on the shaft and a
yellow spot on the yoke and goes on to say:

"ALIGN THE BLACK PAINT SPOT 180 DEGREES OPPOSITE THE YELLOW
PAINT SPOT (my emphasis) on the pinion yoke. This aligns
the light side of the propeller shaft with the heavy side
of the pinion yoke, minimizing residual unbalance. Prior to
removal, be sure to check for the presence of the paint spots..."

If these remarks also apply to whatever your C4 vintage is,
hopefully the spots might still be visible - be careful
when cleaning and maybe you will get lucky.

If you don't find their marks, make your own but use other
colours.

.

found it! I will update the Spicer issues later... after you all debate and come to some sorta agreement on which really is best.

Quote:

When I installed them I put the clip on over the end of the ujoint and pressed it into place. I would go in a little, then release tension on the vise to see if the clip was ready to snap in, if not, then repeat.

I figured this way I only pressed it as much as needed for the clips to seat and no further. It was a very tight fit.