Hi Ken, many thanks, as of the threaded pin I'm well informed because all the pins on the old M. Diesels have that arrangement. Truth of the matter, the bolt was frozen tied, I wiggled it loose with a vice-grip. The bolt arrangement would never have worked originally until the very end when I pulled the pin after broken the grip. Tomorrow morning the head will be out. As mentioned, I ordered a new head paid by check on a Friday. Over the weekend I changed my mind and cancelled. No time clearing the check. However, the dealer was most understanding. After checking out the head I will know more. If a new one is necessary I must eat it up. All the best, Hein