1991 300E power steering fluid level?
 

:book:

Dumb, but simple question, I believe that I need to add power steering fluid but there does not seem to be any "min-max" indicators in the resevoir. The Owner's manual is useless on this topic. Also, the book calls for MB fluid, can I use the GM fluid that I have on hand?

On my 91 300E there are min and max indicators. Anyway, if don't have one I would say half full fluid in the reservoir is about max. Regarding the type of fluid you will find lots of info. if you do a search but the the majority opinion is that as long as the bottle says "Power Steering Fluid" you are safe.

I hope the Dexron III I poured in is OK or should I flush the system?

If the Dexron III bottle states "Power Steering Fluid" it's fine. Do not use transmission fluid. I know there are experts in this forum who know how to flush the system properly but I don't. What I usually do is pump out the old fluid from the reservoir twice a year and pour in new fluid. I also replace the filter once a year (cheap insurance). If you are unfamiliar with flushing out the fluid I would pump out the old fluid from the reservoir once month and change the filter after three months or so. Eventually, after while you will see the fluid get clear and know the old fluid is gone.