This wasn't a technically difficult job, but it takes some work.The '91 came out of winter storage today, and I'd like to follow in your footsteps and either repair the propane valve or replace the tank. The propane must be drained yet, and physical limitations have kept me from getting a good look at the underside. Can you provide any hints on how to get the tank out, or point toward other discussions of this topic?
1. If it's not empty, consider using the propane, because it'll be easier (lighter). But I did it with the tank about half-full.
2. Turn off the valve. Make sure it's off. Make sure the system is empty, possibly by lighting the stove.
3. Disconnect the propane line to the rest of the system. I disconnected the line from the regulator that goes to the "T" mounted on the frame behind the tank and left that short line on the tank.
4. Disconnect the wires for the gauge. There should be two, ground and positive. Note which one goes where, although it may not matter (I'm not sure).
5. Put a jack under the tank. Use something to protect the tank from the jack. On the way down I used a piece of wood. On reinstall I used a piece of heavy foam that came with some furniture that was shipped to me. Foam worked better because it curved to the shape of the tank. Jack up until there's some weight on the jack. Try to get the jack centered so the tank is balanced, that will make life easier.
6. There are four bolts, two on each (long) end of the tank. Unbolt them. Note where the bolts are inserted both in the tank and in the brackets. Right here it helps to have another person to keep the tank from rolling away on your, though I did it by myself.
7. Lower the jack and carefully put the tank on the ground. Dropping this tank is NOT indicated (it's a blast). I put cardboard down first so I could drag the tank around without scratching it further.
8. Get new hardware, especially lock washers. It's cheap. Just do it. Lock washers really shouldn't be reused anyway.
9. Installation is essentially the reverse - put the tank back on to the jack (don't forget the padding), jack it up to the approximate correct position, put the bolts back in, and tighten them down.
10. Reconnect the line and wires. Check for leaks on the propane line, either using soapy water or the things designed specifically for that purpose.
11. Test that the propane works.
I didn't have to jack the camper up or anything like that to pull the tank out.
Despite my jokes above, I think working on propane tanks is actually pretty safe, as long as you are careful. Ever watch Mythbusters when they try to blow one up? They really have to work at it. Obviously, don't do something dumb like turning on the gas while the line is disconnected!
Next up, I noticed that the brackets are loose, somehow. My next step is to replace the bolts for those. I plan to do those one at a time, so that I don't have to lower the tank again.