SOME DRIVE-SHAFT QUESTIONS

[MIDNIGHT RIDER]

My 1985 long-wheel-base F-350 chassis-cab has a two-piece drive-shaft with three universal joints and a carrier-bearing.

Way back when in un-molested factory-original configuration, for reasons un-be-knownst to me, both ends of the assembly had "hybrid" joints, with differing cup-sizes, and a normal joint in the center.

Why did Ford opt to utilize these weird two-sided universal-joints, instead of making all three joints the same ??

As delivered, it requires two different part-numbers to equip the shaft with new joints, plus the aggravation of having differing cup-sizes to contend with; common sense dictates that it would be much more sensible to use three normal joints.


For what it's worth, I measured a brand-new hybrid Spicer joint, 5-1204X

According to my findings, at least on a Spicer joint, the dimensions of the two sides of the cross are identical, both in bearing-surface diameter and length, meaning that it matters not which side of the cross has which size cup.

Prior to actually measuring the cross, I had always assumed that the cross would have differing dimensions to go with the differing dimensions of the cups.


----- Of course, my shaft now has THREE different joints, a huge Dodge/Cummins joint at the transmission end, a normal Ford joint at the center, and the weird hybrid joint at the differential.




Another question:

The splined slip-yoke at the center of the shaft has some sort of ?plastic? collar that I have never yet figured out whether it is removable such that the splines simply slide on/off.

On every other shaft I have ever dealt with, there has been a threaded metal collar that is easily un-screwed with a pair of channel-locks.

Ever since I have owned the truck, many many years, seeing no other feasible option, I have always left this collar intact when pulling the shaft apart --- not an easy task, especially when re-aligning the splines and re-assembling.

Surely this collar is meant to be removed; how does one go about this ??


Many thanks.

 

[LCAM-01XA]

What you have from the factory are not hybrid U-joints per se, they all have the same 1330-series cross and as you measured yourself the caps can be moved around on it as you see fit. The joints at the ends of the shaft simply have two caps with thicker walls and thus larger outside diameter - one theory behind this is that it was done to resist cap deformation (and thus freezing/binding of the joint) due to overtightening of the u-bolts that hold the caps into the transmission and axle yokes. As far as I know this was only done by Ford and only on the 1330-series joints, the larger 1350s do not seem to come in a big-cap variety. Not a whole lot you can do to fix this situation, if you have a Dana 70 axle you may be able to find a standard-cap yoke for it from say a Dodge or something, not sure if Ford ever made one that was not of the big-cap variety. Now if you had a 4x4 truck then I could tell you how to obtain a standard 1330 yoke at least for the transfer case, but since you're running a Getrag transmission that wouldn't be of much use to you...

About the slip joint in the rear shaft, I know exactly what you're talking about, but for the life of me I can't recall how it comes apart.

 

[MIDNIGHT RIDER]

About the slip joint in the rear shaft, I know exactly what you're talking about, but for the life of me I can't recall how it comes apart.

But the collar does somehow come off, right ??

 

[LCAM-01XA]

The only time I had to deal with this collar I think I carefully tapped it off the driveshaft by means of a piece of metal plate and a small hammer - this was in junkyard conditions so I couldn't get fancy. In shop environment supposedly you can use a heat gun to soften the plastic a bit, then grab the collar with welding gloves and pull and twist till it lets go of the shaft and slides off - I've never done it myself tho, so I can't say for certain yay or nay on this method...

 

[MIDNIGHT RIDER]

Thanks so much, LCAM-

 

[MIDNIGHT RIDER]

>>> ONE MORE QUESTION <<<


I was looking at carrier-bearings / center support bearings at Rock Auto.

So far, my original carrier-bearing is still doing it's job.

Considering it has a blue-million-miles on it, I sort of thought I would go ahead and get a new one just to have on hand if and when the need ever arose.


Problem is, like most anything I seek on Rock Auto, they list no less than seven different bearing I.D. choices; 1.378, 1.38, 1.5478, 1.5748, 1.7717, 1.9685, 2.3622


Seeing as my bearing is still on the shaft and still in service, how do I know which one I have ??

The truck is my 1985 chassis-cab F-350, originally 2WD diesel 4-speed.

Thanks for reading.

 

[LCAM-01XA]

Grab a pair of digital calipers and measure the shaft diameter right next to the bearing, on the slip-yoke (rear, towards the axle) side? Should have enough space between the slip-yoke and the bearing to slip in a pair of calipers... I'd try getting a measurement on the other side (front, towards the transmission) too if possible, just as a peace of mind. Kinda doubt it will be any of the largest two tho, seeing how the shaft tube itself is likely 3" or so in diameter.