NAA stopped lifting weight

[Soundguy]

time for you to buy a manual.

that is not the pickup tube. that's a back pressure valve. it works with the unloader valve. hyd fluid moves up the side of the center housing in the pip you can see in one of your pics, then transfers to the top cover.

base of the trans has the relief, near that pressure tube. also the plumbing unde rhtere will be visible to the hyd pump. pressure and suction lines.. etc.

Alright, here is what I'm looking at. I took the acorn nut off the side of the body, there is just a spring in there. I took the spring out, turn the tractor on, and a little bit of hyd fluid squirted out when I moved the quadrant lever around. I took the lift top cover off, and I don't see any sort of oring around the valve. I assume it is threaded into the tractor body, then the pickup tube is pushed into the side of the valve? It doesn't just push through the body, but it will turn. From what I can figure, the way that the whole system gets the fluid from the tank to the piston is that one hole in the bottom/side of the top cover that just rests against the pressure valve? If that seal is bad or not tight enough, then it's like poking a hole in straw, right? The fluid looks like it would be low to me, but the stick says it's good. What do ya'll see?
Thanks so much for helping me through this!

 

[Cbrown9064]

only the naa has the acorn nut..

might want to invest in a service manual for your 00 series.

Yes, have both the Ford reprint and the I&T. Only have the I&T with me and it didn't say anything about the nut. That's why I was curious.

Thanks!

 

[Soundguy]

it's an updated design with integral back pressure valve.

the naa was a quick hash / hyd changed over fromt he old N style belly pump to get away fromt he ferguson lawsuit. so the naa was a stopgap red headed stepchild. much less parts support for an naa from trans and back as it only had a 2yr run...

 

[seanpaintsflames]

Okay, I finally got a gauge on the remote hydraulic tap. With the tractor running and a 6ft flail mower on the back, it is making about 500lbs of pressure. If I rev it up it will make close to 750 lbs. What kind of pressure it is making? At this rate the mower will barely lift off the ground. I don't know how much the mower weighs, but it would make sense that if it weighs 800 lbs it would need at least that much hydraulic pressure to pick it up. Maybe the pump is in need of a rebuild?
Thanks!

 

[Dollar Bill]

Mid throttle it should produce at least 1500 PSI. If the lift just suddenly stopped lifting, I would suspect a valve problem. Now that you have to top cover off, it's too late to check for leaks/turbulence - The milky oil is an indication you have water in the hydraulics - Steel + Water = Rust which is likely causing problems with any number of the different valves in the lift system.

 

[seanpaintsflames]

I've had the cover back on for a couple weeks, so I can look inside. What would I be looking for with a valve problem? are you thinking that there is a piece of rust or something in the block that attaches to the lift cover? For what it's worth- I didn't see any rust in the system when I drained and rebuilt it last year. There was a lot of chunky oil gook, though, and although I though I cleaned it out really well, I suppose something may have gotten in there.
Is there a way to flush the whole system?

 

[Dollar Bill]

As you're only getting about half of the pressure that you should see on a pressure gauge, you have either a problem with the pump output, a leaky gasket or a valve that isn't seating properly.

Since you now have it back together, pull the side covers off and load the lift - With a flashlight/mirror, peek inside for leaks (lift cylinder, control valve, safety valve, check valve, unloader valve) - If the safety valve were leaking you could see it dripping toward the back of the ram cylinder on the right side.

 

[Soundguy]

go back and redo the hyds test. chain the 3pt down.. then run the lift up.. see what pressure she makes.

 

[DaveOmak]

Looking at the hydraulic case, and the dip stick, it looks low on oil..... and the white color in the oil is air.....

Dave

 

[Soundguy]

the sump is not intended to be ful pouring out under the seat.

air entrainment settles out fast. water emulsification does not. ( settle out fast )