After an encouraging consultation with my dentist in Mora, I came home and got busy moving vehicles around so the Jeep would fit in the shop. Once I had it parked inside I took a lunch break.
Jeep-window-regulator-broken-part It didn't take too terribly long to get the window regulator out of the door. It is a little like a Rubic's cube. Once it was out I could see what the problem was. The Internet guys were correct, this is not a solid design. I've seen worse. Apparently the springlike thing is supposed to be attached to the plastic bracket which in turn is attached to the window. It looks like the spring was cast directly into the plastic. It isn't surprising that didn't hold up. The gunk covered cylinder rides inside a track along side the main window guide track.
After brainstorming while I cooked dinner, I had a thought: Perhaps a fence staple wrapped tightly around the spring, and formed to fit in the track, admittedly super-tight, then pass the points of the staple through the plastic bracket.
After dinner I set about locating fence staples, drill, with assorted bits similar size to the staple legs, a Dremal Tool to make it fit, two pair of needle-nose pliers, and a Weller soldering gun for fine adjustment to the plastic. The plastic looks to me like HDPE (high density polyethylene.) Not an easy plastic to weld, but pretty easy to melt.
Jeep-window-regulator-modded-part Sorry I didn't get more pictures of the process. The reason is I had my hands full getting the staple to fit in the track sufficiently to allow smooth movement, while at the same time installing the bracket and placing the staple inside the track as well as placing the staple in the bracket.
Above is the staple where it penetrates the plastic bracket. I may be wrong, but I don't believe there is any lateral force on the staple, so I didn't get carried away bending the legs over. The remaining piece of plastic seen in the first image (shown covered in black grease) will hold the spring down. I had some difficulty getting the spring back in the plastic track guide, I think it was worth the trouble. If this works it should save us a hundred bucks.
Jeep-window-regulator-reassembled I need to get showered and go install the window regulator, although I'm here to tell you apprehension levels in this modder are fairly high. I'll be happy if for today this thing holds the window up so I don't need tape on the glass.