UPDATE: The weather turned nice this weekend, so I decided to give the shocks a try. I employed several of the suggestions that were offered. Once the wheel was removed and I got a light up in there, I could see that the threads of the shock bolt didn't look too bad, so I wire-brushed them and soaked them with PB Blaster, then I fabricated a sheet metal shield and was able to get it behind the bolt to protect the bed wood. I heated the nut and bolt, but it was still a bit precarious, even with the shield. I was able to get a short 9/16 box end wrench on the nut; unfortunately, when I tried to turn it, the entire upper dust jacket of the shock turned with it. Luckily I was able to jam the box end wrench against the side of the inner wheel well, and I began to turn the dust jacket with a good sized pipe wrench. This method seemed to be working, but the fine threads on the bolt made it slow going. In addition, the pipe wrench was taking its toll on the dust jacket. I kept at it and it kept turning. Finally, I was no longer able to get a bite on the jacket with the pipe wrench. I then switched to a very large channel locks, and continued to turn. The nut stopped moving, but fortunately after several more turns, the bolt snapped off and the top of the shock was free. I had determined that if I couldn't continue to turn the shock with the channel locks, I would cut back the dust jacket to get at the lower part of the bolt; luckily it snapped before that point.
Concerning the suggestion of grinding off the rivets to remove the shock mount, some previous owner of this old truck already had that idea--the shock mount was fastened by nuts and bolts, so a PO obviously used that method to replace the shocks at some point. However, I was working on the passenger side shock and unfortunately I could not get at the bolts and nuts because the gas tank is mounted there, right up against the frame, and in order for me to remove the nuts and bolts of the shock mount, I would have had to remove the gas tank to get to the other side of the frame rail (and dropping the tank and replacing it is not a simple procedure--I know because I replaced the tank a while back). I only had time to get the one side off, so I'm not sure how it will go with the other side; but having done one successfully, I'm confident I can get if off one way or another.
Thanks to all who contributed suggestions--I felt more confident tackling the job, having several plans of attack in case of running into problems.
Jim
