You just have to order a Hill MKIII kit and it's easy to rebuild. Hardest part is breaking it loose the first time. After that you do NOT need to make it that tight. It will NOT leak if you tighten it as hard as you can by hand. If you use a wrench don't tighten it as tight as it was. You could mash the rings. I've rebuilt many pumps and Hills have never even needed it. I just wanted to see if there was any rust and rebuild and learn. All seals were fine. I use 100% plumbers silicone grease. Sparingly but enough to cover rings completely. The static or friction bearing orings need a little more. Lube not just the rings but the surfaces they glide on. They're instructions to be found on Youtube but if you're not confident I'll gladly rebuild it for free. You just pay shipping to Pennsylvania & back. Everyone was selling the rebuild kits for $35.00; but now one of our sponsors, "The O-ring Store" has a header on The classifieds. It leads to his eBay page and you can pay with any credit card. Just click where it says pay pal but you don't need pay pal. It'll give you the option of using any card. You can't beat $14.95 as the original price of $35.00 is insane. I swear by Hill pumps; but my next one may be a G6. Much cheaper, and comes with 5 full rebuild kits. There's also a new one called "The Brute" or Brutus, something. It's supposed to be built like a Hill with tight tolerances and very well made for the price. We're going to see a lot of new pumps & compressors coming out. You can't go wrong with any model Hill. I find pumping to 2K easy peasy. 3K a little harder. The G6 and some other pumps go as high as 4-4500psi and are good for high pressure big bores. I'd hate to have to pump that high every 2-4 shots and I don't know how long a pump that goes that high will last between rebuilds. 3K is good enough for me at the highest.
Email me if needed firstname.lastname@example.org 15 pages of 100% positive BOI and will gladly rebuild your punp for free. Just buy the kit, a $4.00 container of 100% Silicone grease, & pay the shipping. I'll have it as good as new. You should learn yourself though in case you ever have to rebuild in emergency and need to know how. I keep 3 rebuild kits on hand. I theoritically have enough for a lifetime. The extra G6 or another Hill I want is just in case of a catastrophic failure, bended rod, run over or something.