I pulled the leaky wheel cylinders off my patrol today. I did some internet searching and came up with the following w. cylinders. The ones off my patrol are "Tokico" brand. Check out the link below. I think these are the right ones.
For a 69 Nissan. Incidentally, spoke with a Nissan parts dealer and he said the front w. cylinders for my patrol are available. Not so lucky for the rear, but the above link seems to be the ticket. The part numbers are the following:
Rear (both) 44100-44011
Front (right) 44111-35003 $58.00
Front (left) 44113-35003 $53.00
Thought I would pass on the info.
Jason