Keeping upper idler rollers lubricated

[towntw]

I'm starting work on the 1955 40C I bought last fall. First item before driving it around much is that one of the upper idler rollers was frozen up.

I removed the idler, arm and all. Once I had the cap and thrust plate off, it started rolling. But it was dry and full of dirt.

Here is my conundrum. The early five-roller crawlers had a solid roller and a grease fitting at the end of the shaft in which grease could be pumped. The later five-roller crawlers had no grease fitting, but in the roller itself had an opening with a screw-in plug. You'd remove the plug, fill with 90W or 140W oil, then screw the plug back in. It appears in my case, I may have an early roller (no plug) installed on a late assembly (no grease plug).

The roller is otherwise in good shape (no flat spot), so I don't think it had been seized long.

Any recommendations on how I should move forward with this? I could potentially drill/tap an opening and make a plug, if that makes sense to do.

[Lavoy]

Early idlers had a 1/8" npt fill plug, next generation, one of the cover bolt holes is driller all the way through, and you put oil in that way.
Lavoy

[towntw]

I'll look for that. Thanks!