e34 or 35

Has anyone here replaced a PYI dripless shaft seal with the updating kit for their E30, 32, 34, 35 or 38? The directions begin: 1. Unbolt the shaft coupling from the transmission coupling. 2. Remove the shaft coupling from the shaft. First question: Is it really necessary to unbolt...

Does anyone know where to find a polar diagram for the E35-3 or E34? (These are the velocity made good charts for all points of sail) I understand they can be ordered somewhere for a price (probably too high). Anyone know how to reach the designer, Bruce King, who might have it?

Has anyone noticed a water tank problem I have encountered on my 1987 E34? (Could also occur for other similar models.) Water somehow was getting from one tank to the other, but not consistantly. Just when I thought an unused tank should be full, it was not. At other times is was. I think I...