Great thanks for the advice.
Great thanks for the advice. I think I'll stick to the grub screws. It's a different thread for greace nipples I believeThe sliding joints on both prop shafts don't normally have grease nipples fitted. It's usual to find some flat grub screws in the holes instead. Just replace the grub screws with grease nipples and give them a damned good squirting. Then replace the grub screws.
I didn't bother to put the grub screws back on mine. I chose a pair of low profile grease nipples which I fitted permanently. They're light enough not to cause any balance problems and by using low profile types they don't foul in anything as the shafts are spinning.
I also found it useful to fit slightly longer grease nipples to the U/J's. It just makes it easier to get the grease gun nozzle to sit correctly.