Rebuilding Rear Uprights and rear discs

Before you do anything, I'd try a different gear oil. Try to use one that says it's specifically designed for use in manual transmissions or transaxles. The ZF and RBT spec. calls for a GL-4 oil but many people use GL-5 oils without issue. Many 80W90 GL-5 gear oils are designed to be used in differentials only and are too slippery for use with synchros.

I have bearing Option B in my 74 Euro Pantera.  Wilkinson installed them for me.

I have bearing Option D in the project Pantera that I received in February.  The work was originally done by Dennis Quella.  In the photo below, one of the uprights is partially disassembled and the other is fully assembled.  I spoke with Dennis about reassembly and he essentially said to put it back together.  Wilkinson also spoke to Dennis about and then helped me reassemble it.  The bearings are readily available from Temkin.  The Temkin seals were harder to find.  I can dig up the part numbers.  I think Dennis no longer does this.  The spacer between the two tapered bearings needs a specialized machining process in order to size it just so.  Perhaps call there and leave a message if you want to know more.

I admit that I don't understand how a system with two tapered roller bearings can work without machining the hub to create a stop for the inner bearing cup.

There is also the option of machining the hub in order to install a double row ball bearing (reference 3308-B-2RS) on the outer side of the hub, where the forces are greatest.

Hi this is the first I’ve heard of this option. To help keep track of the available options let’s call this option “E”. This looks like a single machining setup and would certainly help carry the load.

The reason Dennis Quella no longer does the tapered roller bearing conversions is, it’s a lot of work for very little benefit. There’s really nothing wrong with the OEM ball bearings, as long as everything is done correctly; the critical elements being the axles and proper torque. If you feel you need more, do the (easy) double row inner bearing mod. If you want to make the assembly more serviceable, convert to two piece rear rotors mounted on the outside of the hub. This way, you can service the rear rotors by simply removing the calipers. The only caveat is, it pushes your rear wheels an extra 1/4” outboard.

This seemed to me to be the easiest to achieve based on the machines I had at the time. Now that I have a milling machine with a boring head, I might choose another solution.

Just to throw another option into the mix; GT5-S’ have a larger OD inner bearing but still a single row bearing. I had a machine shop modify my uprights to use a larger OD inner bearing. My understanding is, they used a very large lathe to machine the uprights. In hindsight, probably not worth the effort.

FWIW, Wilkinson has the double row bearings and correct spacers on the shelf.

But the double row Wilkinson bearings are the inner bearings, it is better than the OEM but it is not the best.

Rene, it is the inner bearing that has historically been more prone to failure. I suppose that's simply because it's smaller.

On 4406 it was the outer bearings to the point of having damaged the axle because the inner race had rotated around it.

When you look at the geometry it is clear that the outer bearing supports more load and I guess that is why it is bigger.

But I also think that the "huge" tightening torque has not always been respected on all our Panteras over the last 50 years, which has caused many failures.

Amazing - was just discussing this subject over the phone, and look what popped up on my Facebook Feed...  You don't think they are listening?

Nevertheless....

The person posting says all the bearings and seals are still available....

We jumped into rebuilding the uprights, no one has mentioned the obvious, a bad half shaft u-joint!

Joules - Don't you think we all want to make this as hard, and as complicated as it could possibly be?    And we haven't even had a chance to begin listing the catastrophic consequences that could possibly occur!

(Smiley Face - Joke, Joke!!!)

Rocky

PS>  That's a good suggestion you provided.

@joules posted:

We jumped into rebuilding the uprights, no one has mentioned the obvious, a bad half shaft u-joint!

Just asking… how would a half shaft U  -joint know if you drive straight or around a corner… is there a load difference on the shaft I don’t see?

no noise straight but noise around a corner regardless left or right or of any load or speed..

I can’t figure it out… 🤪

Cornering the car will unload weight on one side, compress on the other and one wheel turns faster than the other. Re-reading I see the half shafts were rebuilt so maybe not that, but also no information on type of noise.

Another option while you are in there is to switch from half shafts to full CV axles.  I have them in my 74 Euro Pantera that has the Option B double row bearings.  It is a very smooth setup.

Where did you find the CV joint locking tabs?

I think the tabs are there to stop the sealing cap deforming and leaking grease, they are somewhat useless in locking a round head Allen (socket cap) bolt, to ensure security the way to go would be drill and safety wire. I always change the boots for the Aero style, much less prone to tearing and can work at more acute angles.