In this case, referring to my Lyman case trimmer. The bushing was worn to the point of where the trimmer shaft had some wobble, which is bad; wobble tends to mean case mouths might be uneven, and so it had to be replaced.
A call to Lyman produced a new bushing*. You're supposed to have a arbor press to remove and replace things like this, but there's a way around that if you have a vise that will open wide enough.
Here's the trimmer with the shaft removed:
The shaft goes through the bushing, which is in that hole on the right; it has a collar on the outside, so you have to press from the inside-to-out to remove it, and here are the tools that allowed me to do that:
Pipe nipples. Left is a 1/2x1.5", right is a 1x2". The 1/2" is just right to fit onto the inside face of the bushing, the 1" is large enough to fit over the collar on the outside. It all fits together like this
You have to be careful to keep everything straight, and the ends of the nipples square on the surfaces so it'll push straight. Once it's in place, start turning the lever to start pressing, and it'll push the bushing out and into the large nipple.
Almost done! About one more turn pushed it all the way out.
Old bushing on the left; new on the right.
Installing the new bushing is almost the reverse of removal; the difference is that for most of it you don't need the nipples, only the 1/2" right at the end.
Clean the bushing hole out, so there's no old grit or other crap that may have sneaked in over time**, then use just a dab of suitable oil or grease wiped around (unless directions specifically state otherwise, I'd never try pressing something like this in without lubrication). Adjust the vise to suitable opening, put the bushing in place, get everything square, and start cranking.
New bushing from the inside...
... and outside.
Yes it's a metal body with a Delrin liner.
Reassembled and back in service.
You can do the same thing with lots of stuff that needs a bushing or bearing replaced. Yes, a press is better, but this'll work nicely as long as you keep everything straight.
*I can't say a bad thing about Lyman. I sent an e-mail: "Can this bushing be replaced, or do I need a new trimmer?"
"Send it in and we'll do it, or if you have a arbor press you can."
"Excellent. If you send one, what's the cost to this address?"
"I'll send you one."
Hooray for real customer service!
**I bought this thing used, and the previous owner had it for years, so there's no telling how many cases have gone through it.