Cat offered the #44 pump option to fit the J series D2's but good luck in finding all the necessary parts.
The La-Plante Choate aftermarket system which would be about right for your year of tractor actually had a steel welded tank (some round, some rectangle), rear mounted Bee-Gee pump and schedule 80 galvanized pipe. So your Rube Goldberg may not be that far out of line. A belt driven pump means you have "live power" which means when you are playing in the dirt, you can raise the blade while stopped.
Is it a 3J or a 5J?
Let everyone know as someone maybe has what you want.
Jeff
http://i32.photobucket.com/albums/d48/R_G_S/CAT%20D2%20Project/FarmFresh1.jpg
Is this what it looks like?
[img]http://i32.photobucket.com/albums/d48/R_G_S/CAT%20D2%20Project/FarmFresh1.jpg[/img]
That looks like a decent farm tractor! They usually have better undercarriages on them because Farm work is not as rough on them as if they were Dozer tractors. 👍