Originally Posted by
yonkie
Right - so if things look to be in good shape, not pitted, etc., then I don't have to replace anything?
You'll want to replace the balls, at a minimum. Once you have the spindle out, check for pitting in the ball track. If you find pitting, you'll want to replace the spindle, or perhaps go to a cartridge unit instead.
I think I need some specific tools.
Quite possibly. There are different tools, depending on what bottom bracket you have. This tutorial might help you sort it out:
https://www.parktool.com/blog/repair...e-cup-and-cone
Also, a little advice on down shifters? This seems like it should be really standard sizing, by my thinking, but mine don't seem to fit. Is this a case where you force them and by force them, I mean carefully, but purposefully make them fit because it's just some variation within standard manufacture, wear over time, etc.) or are there other sizes?
There are several types of downtube mounted shifters. Some mount on brazed-on bosses, others use a clamp. What do you have now? If yours have a clamp, the only concern is matching the tube diameter to the clamp. Braze-on bosses come in several varieties, but the most common is the "Italian" (aka "Campagnolo") style. Shimano "A" or "B" type bosses are possible on a Japanese bike.