Originally Posted by
louisvanhovell
Thank you for the advice. You're right, I should have left the pump cup and tried it after resealing the rest.
But yesterday evening I was in this disassembly mode, and that can be a dangerous thing: I then really want to solve each problem asap, and this sometimes leads to hasty decisions.
I cut off the old pump cup and then tried to unscrew the brass nut, using not leather but thick cloth - no movement, and some minor grip marks. Damn. I used a diamond file to repair the light grip marks, and it's all good now. But still this nut won't move! I will try using a piece of leather tonight. A new pump cup will indeed mean that I can experience the best possible functioning of this 107.