It all depends on how you value your time. I’ve rebuilt a few but now I toss them and put on a new crankcase. A couple of years ago I got a Cat 310 pump stash from a car wash that went out of business. When a head would wash out or need seals they’d toss the complete pump, put on a new one and press on. A couple of them were like new, just needed seals. In 38 years I’ve only had 3 pump cranks fail. I stopped changing the oil in them years ago, I add oil now and then.
Odds are most of the crankcases aren't even bad. Some people buy new pumps when the manifold goes bad and keep the old crankcase. If the shaft turns smooth and quiet and the plungers are tight with no play, it should be good. It's probably not worth fixing the one with the broken rod if you have a bunch of potentially good ones, especially if they're Cat pumps. They're not easy to disassemble, and you have to be careful and know what you're doing or the repaired one won't last.
