I found these front idler shaft bushings in idlers off of a 3j. My 3j book shows a different part number as does my 5j parts book. My 3j book starts at serial number 1 but the 5j book starts at serial number 3501. Maybe early 5j or 22.
Looks like the casting number is 1B253


 

Idler bushing for D2, fits J models and U models up to 4U3610 and 5U6128, and was used in the 22.

Thank you for the info. One more question just for the sake of knowing.
The front idlers that I'm using came off a 1941 5j, no history on the machine other than the engine tag and transmission tag were 1941. The inserts that are in the idler housing are steel with a bronze bushing. Any guess on where they came from. Thanks again

I would say that someone cleaned out the idler casting bores made the steel sleeve then rebushed it. I have done several of these. The bronze casting ones you posted earlier look like bushings from a 22 or similar.
I have bored those out and made bushings for those as well.

Well it looks like we have a mystery.
My 5j parts book form #6511 printed February 1941 shows part # 5b9364 bushing for the front axle shaft.
The bushings I took out of the front idlers with the steel centers are stamped with the 5b9364 number. It doesn't seem likely that Cat would put a bronze bushing in a bronze hub. So I guess I'm still kinda curious as to what the brass hubs and the steel hubs actually were in originally.
Just from what I saw from cleaning the steel hubs they look like original equipment or very well made replacements

The 1B253 bushing was the original part in the earlier D2's, many parts changed as time went by. My guess on that part would be, as brass or bronze became more important as a war material, it made more sense to make the part in two pieces that used less brass and was more easily repaired than just a one piece bronze bushing that might required less machining.
The 1B253 was used in the 22 idler also.

That makes sense. Thank you for the information