After rebuilding mine several times it had finally come to a point where I needed a new one. I looked around the net but all I found was a new bottle with pump for something like $80.00 !
I thought why not try the obvious and call Shucks, they've surprized me before by having parts for older cars I own. The guy at Shucks said that they carry a full line of Trico Super Pumps and the one that was listed for my 72 240Z was their "universal" pump. Well I really wanted the stock pump so I got on the Trico web site just to see what they had available. Much to my amazment, Trico carries a pump that is identical to my original Datsun part, the Trico part number is 11-601 and it says that it is for Honda cars only, go figure. Actually, there is a slight difference, the black wire has a spade connector and it need to be a female type, that took about 2 seconds to fix. I put it in and it works great, it was the last thing on my car that didn't work so I'm real happy to have found it.
Anyhow, if you're in need of a new stock washer pump, you can easily get one for $27.00 from any autoparts store that carries Trico pumps.