The power steering system suddenly started weeping really bad, it was burning up against the engine and smelled like melted crayons. I jacked it up and there was ATF all over everything on the left side underbelly of the engine bay. It seems as if when you steer the wheel to max one way it triggers the pump and the high pressure hose from the pump to the gear shoots out a stream of ATF onto the side of the engine. Nasty.
https://imgur.com/PZxKVYt
You can see the stream in that photo. At least this confirms the pump works!
I ordered an aftermarket hose and hit everything with some degreaser. When that hose comes in I will also change the power steering filter and refresh the fluid with some proper MB power steering fluid.
Fuel Level Sender
I mention in my first post that the gauge in the dash will go to about a 1/4th tank and then sit there until the warning light goes on and when that happens there is only about a gallon in the tank. So I figured I'd try to pull the sender unit.
The unit itself was super clean, I didn't see any signs of buildup or corrosion on it so there wasn't any obvious reason it would malfunction. The float seems to travel fully though the tube as well. I hit it with some brake cleaner and contact cleaner and assembled it all back together. Will have to wait and see if that fixed it.
It took a bit of digging to find the steps I needed to pull it as my 91 560sel is a little different in some places than other w126 so here is a step by step what needed to be done if you have the electronic adjusting rear heated seats.
https://imgur.com/a/Kj3AZkA
1- two bolts on both sides of the rear seat easily accessible from the footwell.
2- shift the bench forward to give yourself access to the bolts below the backrest. I did not need to disconnect the connectors for this job.
3- unbolt the three bolts that hold the backrest to the frame, not the two bolts that hold the frame to the electric track. I attached an image that shows the right and wrong bolt. You want to leave the lower track bolt in.
4- lift the whole backrest UP to unhook it from the frame and lay it down on the bench. This will reveal the access port for the tank and sensor.
5- remove plastic cover and disconnect the fuel sender electronic connector. It pulls right up with no clips.
6- with a 46mm socket OR 1 13/16th inch socket loosen the sender assembly from the tank.
7- get a bin or something to catch the fuel that leaks out as you remove it. It will be full of fuel and has little holes at the top and bottom where it leaks out. You can also pull the tube up enough to where the drain hole towards the bottom is no longer submerged in fuel and you can hold it there to let the fuel leak out back into the tank.
8- once you have the sender tube out you need to get creative with removing the small nut at the bottom. I used a fine point wire cutter to turn the bolt but I have seen guys drill a hole in a flathead screwdriver to mimic the function of the proper tool. Its almost like you need a tiny 2 prong fork for ants to stick in there and turn it. Try not to damage the plastic tube around it.
9- once that bolt is off you can pull the mechanism gently from the housing. check for broken wires, just for corrosion or gunk buildup. Check the float can actuate fully up and down the device.
10- clean everything gently and reassemble.
Hardest part of reassembly was probably getting the backrest hooked back onto the frame. Make sure you have the seat belts back out around the seat to avoid having to redo this. There is also a little flap that runs across the top of the backrest which needs to be help up by something while you lift the backrest up and back onto the frame. I used a little bracket from some old window blinds.
https://imgur.com/a/6NiSwKi