W123, Diesel Engine Repair

I am having problems with my Injection Pump Shutoff Valve...when I first start the car up the Valve is in the upright position..when I shut the car off it stops down and shuts the engine off. Then when I come back to restart the car a few minutes later..and turn the key to start..the engine turns over but will not start because the Shutoff Valve is down, but when I immediately turn the key off then back on, it comes up and starts the car immediately.

The steering box on my 280E is leaking fluid. It appears to be from the seal near where the pitman arm attaches to the output shaft. My local Mercedes specialist tells me that this is a time consuming and expensive repair involving a strip down and replacement of the (many) seals within the box. Although I intend to get this done in the next few months, is it worthwhile in the interim flushing the system and adding a power-steering stop leak product to the new fluid, or is this just a waste of time?

n/a All wipers have quite working. New wiper motor on rear hatch, new relay, and horn does not work. Horn is on the same circuit and fuses were good but I replaced the wiper/horn fuse any way. Rear wiper quite working first, then windshield wipers began failing intermittently and now are completely non functional. Ground issue?

After replacing wiper relay and wiper /horn fuse and checking for operation system did not function, then after setting overnight and starting in the morning wipers and horn worked, and have worked ever since. Is there a reset function happening here?