Hi David,
Sorry for the delay in this reply, had not been watching out for you!
I will have a look in the pack of docs I have, but I think it's only the original notes that Bill supplies, nothing manufacturer specific. (But, will check anyway!).
But, I rather think that the issue is more likely to be in the hydralic tube & arm in the keel box rather than the pump unit in your locker. Millions of these pumps have been made and most trucks with a tail lift seem to have them on too, which is very reassuring! If they are truck driver proof, they have to be ok for us!!!
So if it's not the pump, then it might be the tube itself? Have you checked the end cap at the bottom of the tube recently? This might made, as mine was, of cast iron? Which is softer than steel and can corrode. In 2006, we noticed a small amount of corrosion just inside the inner lip & where stainless tube passes close by. To be safe, I decided to have a stainless steel copy machined up in Portsmouth with some brass sleive inserts to protect the steel arm. Had had no issues before or since, & touch wood .... works great!!!!
My boat 37 is 1998 build, so No 40 is maybe, year 2000 build??? ie 8 to 10 years old. So roughly the same age as mine was in 2006, when we noticed some corrosion? It's just a theory, but I think when you said "for about the first third of travel and when raising the final six inches", I thought about the end cap? You may have a small amount of corrosion rub in there?
This is not a major issue and I very much doubt you are even loosing any hydaulic oil, and if the seel arm is ok (which I'm sure it will be, as it's made of very hard steel & should be quite robust)? The fix is realitively cheap & simple. Either order a new one (via Bill) to replace it or have a new one machined. Unfortunately this is a bit of a winter job, rather than a new one, as you have to disconnect the tube from the keel and pump remove the whole thing.
I'm not sure where you are based, but the first thing you need to do is check, then if it is this & you need technical assistance I will be happy to pass on to you my contacts here in Portsmouth or you can talk to Bill.
As said it's just a thought and might be worth a look during the next winter lay up and as said, it's not major, just a maintenance issue, otherwise I would not be discussing here! Our boats are wonderful and we want to keep them valuable!
Regards,
Stuart