Thanks everyone. I picked up a lm25uu bearing to try. However, as Toolmaker51 mentioned, they did not bore the back end to size, it is approx 1mm under size.

And the other lm25uuu bearings installed are half-length. It would have made sense if they had used the 3 bearings triangulated, but they did not.

Thanks Elizabeth for your offer, I'm going to try to get the LM25UU in, since I've already got a replacement.