Going through this now… I have to replace the shift fork on my MTD tiller, and the wheels are stuck on the shaft. I bought it used a couple moths ago and finally am getting to work on it. I don’t think the wheels have ever been off.The tiller shaft is tapered and they can grow on. You can remove the long bolts and spray PB or WD in there. Let it soak overnight then use a long punch or pipe and a hammer and it it from the back side. They will or should pop off
Another challenge is removing the wheels if they haven’t been removed. The first one I had I drove the roll pins out and had to heat the inner part of the wheel with a torch. I used a pipe wrench and tried to rotate the wheel to break it loose. It’s a good idea to remove the wheels once a year and clean and lube the axle shafts. If they get stuck it’s a pain if you need to replace or repair a tire
I do not have an air hammer, but I do have my grandfathers 4oz ball pein (gotta be at least 90-years-old or more) that has a wonderful rebound and I can rapid-tap almost all day . The pins came out fairly easily, but the wheels are being recalcitrant. It is only Day 1 of disassembly, so I have several stages of brutality to go through yet. . . I did warm it up gently, just enough for the merest wisp of smoke and a slight softening of paint, and it is going into the low 30s/upper 20s tonight, so I will hit it with the torch again first thing in the morning to try and get a better expansion of the wheel metal over the heavier solid shaft.If you have an air hammer, the rapid tap/tap/tap can help vibrate the parts so the penetrating fluid can do its job. But you don't want to mushroom a pin so it can't be driven out.
Heat might also help get it loose.