I stuck to hydraulic pump back on the tractor today to see what the symptoms are. There appears to be some fluid flow, and the lift will track the position control lever very slowly as long as there isn't any weight on them. If I stand on the lift arms they go back down, even with the position control up. It would appear that the lift piston probably needs new seals.
I pulled the pump back off and opened it up and it looks ok. The pistons don't seem to have any notable scoring, the valve balls look good and the valve seats look ok as well.
I pulled the line set off so I can clean them out, and I guess I'll be pulling the lift cover so I can tear into that and also clean out the hydraulic sump fully. I did drain the fluid after the test and it didn't look bad, probably fairly recent. It will be replaced with UTF once I do seals on the piston and anything else I find wrong.
Also, I can't seem to budge the test plug, which is going to make it rather difficult to install a pressure gauge to see what pressure I'm getting.
I haven't done this on the NAA, but I'm pretty sure this part is identical to the 8N. You're in for a treat, they used a piston and rings like in an engine. It will be scored, at least mine was. I bored it out and made custom over size rings and a custom piston. Luckily I know a machinist.
I would suggest tractor transaxle fluid. Just a bit heavier than ATF. Cheaper too. Available at any Fleet and Farm store.
You know you don't know squat about diagnosing hydraulic issues till you got a pressure guage. I'd find out if you got good pressure and flow first. You may want to start a query on removing a frozen pipe plug. I'd probably weld a nut on to the plug.
There's also an inspection hole on the right side for the hydraulic. I'd pull that and observe for major leaks while trying to lift some weight.
Another thought, are you sure the hydraulic pump is fully primed? If you've still got air in there, you'd have similar symptoms. But that's back to pulling that stuck plug. Of course, if your inlet screen is partly plugged you'd have these symotoms too.
You found a hole in my old ford knowledge. My NAA is the backhoe tractor. While I've had this tractor and used it hard for over twenty years, I've never once had need for the tractor's hydraulic system. Sounds like your NAA is the same as the lift assembly on the Ford 860 with the exception of no leather.
I'm glad to see you don't have the 8N lift. Not one of ford's best designs. But, keep in mind, ford was the first tractor made with a true three point system.
Springs die and leave spools in the wrong position, too. Rebuilding the control will solve it.
You didn't mention springs. They can be crucial to proper workings.
Quick, hot touch of an o/a torch flame on the housing next to the plug usually works. Got hex socket or square end plug? The right tool and a direct line to get at the plug always help.
Sometimes it's quicker to make (or have your hyd line builder (NAPA?) make) up a quick inline test hose. Most of my work has been on automotive power steering and brakes, but I've watched a whole lot of equipment being repaired. (Me strong like ox, smart like trak-tor)
-- Happiness comes of the capacity to feel deeply, to enjoy simply, to think freely, to risk life, to be needed. -- Storm Jameson
The NAA uses the O-rings and wiper like the later 600 and 800 series. Also has the better draft control.
Ford didn't design the three point they used. It was Harry Ferguson who developed a working 3-point. Ford had a handshake deal to use the system and then refused to pay for them once he started selling tractors.
Harry opened his own factory in England and the TE-20 was the result. Then he opened a plant in the US and the TO series was born. This was direct competition to Ford.
I have owned most of both sides of the isle. Ford 8N, 9N, 2N, a 600 and
800 series, plus a couple TO-20s, a TO-35, 35 Deluxe and some of the larger ones as well. Most were good tractors if you used them in the envelope they were intended for.
I wonder if this is true of all NAAs. My machine looks pure 8N on the back half. no live PTO and the lift assembly sure looks 8N on the exterior. I'm thinking for my early NAA, Ford just redesigned the engine to overhead valve and live hydraulics. Then they went to work on the back half and put in live PTO (I've seen NAAs with this) and draft control on the lift assembly.
Of course, its also possible that somebody took the better lift assembly off my tractor and stuck an 8N unit on. After all, its a backhoe and the only function of the lift assembly is to hold the tractor seat in place.
I learned something today. Don't happen often for an old fart.
I've never touched a 2N or the Ferguson. I think my favorite of the bunch is the Ford 860. Plenty of power, live hydraulics and PTO, very simple reliable maintainable design. I've also had the newer 2000 both
4 and 3 cylinder and an even newer 3600. These machines are not as rugged.
The lift control for the Jubilee / NAA has the position control sector lever on the right, a lever inside a ~90 degree cage, with an adjustable position stop that runs in a slot in the cage. The travel of the lever in the cage represents the travel of the lift and wherever you position the lever, the lift moves to the matching position. Pretty sophisticated for a 1953 tractor.
I suspect that it's parts swapping in action. A 57 year old work tractor is likely to have seen a lot of parts changing.
Of course I first saw an NAA just a few weeks ago, and have been reading everything I can find on them (Yesterday's Tractor, N Club, etc.).