[QUOTE=Mike D;3875032]If it comes down to it, the pumps are rebuild-able, including replacing the bearings with improved, caged style bearings.

https://www.youtube.com/watch?v=DWvLY82zcFg/QUOTE]

That's a 617 pump, which is a very different design. I don't know of anyone who has rebuilt a 602/603 pump.

Here's a comparison of the bearings used in the old and new style vacuum pumps.