All,
Thanks so much for the precise details, intricacies, cautions and words of mechanical wisdom you have all provided. Could not ask for more!
Mike, I did speak to your neighbor and he was so gracious with his details and even offered to help fix it in his home garage. Please relay my appreciation.
Well, after looking at the steering gear-box very carefully I felt that the main leak was the large seal underneath, but there were other areas that had very slight evidence of weeping --- it made most sense to have the unit fully rebuilt.
Heeding your advice of caution, I decided that removal and reinstall of the steering gear-box was not a job for me but rather for someone with specific experience with these boxes. Since I did not want to damage anything by driving the car too far with fluid spewing, I took the car only 3km to a mechanic in his 70's who has been working on 1960's Mercedes cars for over 50 years. After discussing how the steering was prior to this failure (no slop, smooth, accurate), we decided to have my steering gear-box rebuilt rather than getting an exchange unit.
The mechanic and his helper pulled the steering box, had it rebuilt locally and reinstalled it without issue. I really wanted to watch the install but had to be at work. The car now drives very nice again and my panic over aligning the spline connection is no more.
I'm very glad I posed the question on our site and very much appreciate your responses. What a great bunch of members!