I read all the posts and ordered the parts listed to upgrade my 250x to the dual bearings like the 300.

My bearings and seals looked fine but it's a worth while upgrade for safety.

The problem is the small oring on the shaft. It seals and bushing the seals ride on to the shaft. The old oring was cut when I put it together. I took the old shaft and got another o-ring and it also won't go together. If you force it the oring is damaged.

I just looked up the specs and the orings are NOT the same size for the old vs new shaft. One is 13x1.9 the other is 12x1.5

If you've done this upgrade and didn't buy a new oring for the new shaft, you'll want to pull the pump and replace the o-ring.