A few questions about grease fittings

[duffer]

I got all the grease fittings under the car pumped with grease but i have a question about the U joint behind trans : how many pumps do i put in there ? do i just keep pumping till no more will go? And the same with the rear axle bearing fitting, how many pumps? And the brass fitting on the water pump how do i grease that? unscrew it? thanks