I see warnings evey now and then for babbit thrust washers in the rear axle.
How likely are they to collapse ?
I ran a T for ten years without any trouble and I am sure it wass still on its original thrust washers.
Replacements are made of what ??

Replacement washers are bronze. The original washers were babbit bearing material and they fall apart with time. If the washer on the side of the ring gear fails, you may lose the use of your brakes. Some of the axles I opened are missing the original washers and they are evident as grey mush in the oil.

Those thrust washer In my opinion were actually die cast white metal or pot metal..not babbitt. Babbitt rarely will disintergrate ,fracture and crumble into bits as these thrust washers seem to do in an axle. If they be of babbitt they would ware naturally ,may get some hair line cracks , but I would think would quickly compress outward, mush and expand (as a rod bearing can)when worn loose from the side play hammering an !.Where as the we know poor grade pot metal is more brittle ,pitts ,explodes,cracks, crazes ,blisters,crumbles etc.

Bas:
If you elect to install modern style bronze replacement washers, inspect the new washers for sand in the lube grooves. These parts apparently start out as crude sand castings, and I recently found this debris in 2 such parts.
Scott Rosenthal

The originals were babbitt. Besides known documentation a simple weight test will comfirm that.

I can say 1 thing,they are nasty to handle if they aint come apart yet.

Bas de Voogfd:

This is a picture of a babbit washer I took out of a rear end today !!!!!

It would be intresting to learn why babbit reacted this way in the rear end but doesnt in other applications.Is it the contents of the lubercant that causes the break down? I put new bronze 1's in the rearend on my project,had to get them machined down some to fit them.

Do the TT trucks have the same washers to look out for? I drained the oil in my rear and it felt like alot of something bad down in the bottom.It did not come out with the oil, but I could feel it with my fingers. Its working ok but I did'nt like what crude I felt in there.

Here's one I pulled out of my rear end. Er, uh... The '25 rear end that is.

When I rebuilt a rear end a couple of years ago, the biggest piece of the babbit washer I could find was about the size of that crescent-shaped piece at the right side in Ken's pic above.

Wel thx for all input. I just have to take it apart I guess to find out if it has been fixed during an earlier resto.

Cheers, Bas

It does not look like a corrosion problem induced by the type of lubricant used is the cause of the problem. Rather the thrust washer wears and has play between it and the adjoining surfaces. Then the shock from sudden side impact loads can cause the part to develop crack(s) and lead to failure. These sharp loads would be akin to the thrust washer being hit by a sledge hammer when transitioning from power to braking.