Ok well here are my photos from the rebuild. Now that I have done it once, it won't take long the second time. I had to cut the access hole bigger and fab a cover for it. I also changed a few things on how the pipe mounted to the L-bracket that holds the outlet pipe. I spent a lot of time fixing the tank monitors but they work now. This is one more system that has been put back better than new that the next owner won't appreciate (ie not eyewash).
Here is what I started with.
First the access hole was too small.
I made a bigger hole using a cutoff blade on an angle grinder. This worked pretty fast.
Here is a closeup of one of the valves showing the rubber coupler.
Here is with the valves removed. Note the sensor wires. Both tanks had the 3/4 and full sensors cross wired from the factory in 81.
Here is a closeup of the connector. Note the purple and orange wire
reversed on the right of the connector. I fixed this by crossing the wires again at the indicator panel.
Here is a photo of the black water valve seal problem. Somehow the seal got caught on the wrong side of the blade.
Here is one showing the crack in the gray water valve seal.
Here is what the mounting flange looks like that stays on the tank. This allows the valves to be removed by having only about 1/2" of play. The tanks would move a little and the rubber coupler had a little movement as well. To make things easier I took about 1/4" off the valve nipple section that fit into the coupler. This gave me a little more clearance. The O-rings on the valves were a bit of a pain to get in properly. I used a lot of vacuum grease to hole them in there. I rebuilt one valve and replaced the other. One valve was glued to the Y-pipe so I just rebuilt it.
I will post a photo of that it looks like when I finished. I straightened the tank flange a little where some idiot hit it with a floor jack. I did not get all of the dent out, but it looks better than it did.
Here is a thread on the tank monitor problems.