As VE9 asks ,how much CAN you lift NOW ???
I'd hate to read 3 pages from now, you've had to buy a new loader control valve because you forgot something or rebuilt your perfectly working one, wrong and destroyed it.
While rebuilding valves is easy, for those who do it '24/7' it can be EASY for a rookie to do a simple 'oopsy' and cost a big wad of cash.
If you do decide to 'open it up'...understand that the entire area and you , has to be CLEAN ! Far cleaner than an operating room, at a level where you could rebuild computer harddrives. Well, not quite but really, really clean. You also need to be 100% sure that everything goes back the way it was, every shim,washer, springs, whatever came out HAS to go back in properly.
googled the part YW23995100 and only got 5 hits ! NO prices, maybe it's not available as a part ?