Can't remove rear wheels.

My usual method now, with thanks to Eric the Car Guy, and this works best in a sheltered garage with a slab, maybe not so good by roadside:

With the wheel an inch at most clear of ground, place 4x4 (or a pair of 2x4's) against inside face of tire, at bottom. And to avoid wheel flying right off, install one lug nut, very loose.

Lay large sledge hammer on slab behind, swing through an arc and smack against the 4x4.

If at first you do not succeed, try again, a little harder.

 

BTW, I fixed the flat tire.

 

Plug repair?

 

Yes

 

Theoretically you can plug-repair without removing the wheel. I've always taken the wheel off though: much easier when you straddle it and use your weight. The last one I did was some sort of ram-set nail, that managed to go in at a shallow angle. And the tire was really deflated, so it was kinda collapsing as we (my son and I) both fought to get the plug right through. I should have reamed the hole a little more, but was used to straight-on repairs.

We got done, but it was a bear. Between that repair (not the first) and with the tire set getting on, starting to crack and all, those loose rims are sitting in the garage right now, new tires getting put on at Costco next Saturday.