Bleeding an IH 444 and 2000 loader

After putting my Dad's IH 444 all back together, we filled the lift housing with 3 gallons of oil, then the trans with 10 gallons.

I started the tractor, first ran the power steering back and forth until it was smooth. Then tried the 3pt lift, that worked smoothly.

I ran the loader up and down a few times, it was very jerky, the pump seemed to be intermittently cavitating with air. I shut the tractor down and put 4 more gallons in the trans. (I was told when the IH 444 has a 2000 loader, it takes 17 gallons total, 3 in the lift housing, which leaves 14 for the trans).

With the 14 gallons in the trans, the loader pump is still not working right, I can't seem to bleed the loader system by just running the boom & bucket repeatedly to their full extents.

Is there some type of bleeding procedure for this tractor + loader?

I own many HYD machines, CAT and Ford, I have always bled by just running the circuits to the extents a few times.

I'm wondering if this IH 444 has a bad pump on the front. The hydraulics have always been jerky.

Also, when the tractor is shut off, the 3 pt falls pretty fast with an implement attached, it doesn't stay up like it used to.

Do not know your tractor but on all the loaders I have ever messed with it is a simple run the cylinder threw there cycle and that will bleed them but if your tractor has a filter in the system I would check it and make sure it is not clogged up because if it is it will cayuse that type of problem

Thanks, yeah, I replaced 2 filters and cleaned out the metal screen filter.

I think the next step might be to take off the pump and disassemble to see if the wear plates and/or gears are damaged/worn.

It seems to pump oil for about 6-5 seconds, then cavitates, repeating that cycle over and over.

if your valves for the loader have built in check valves that can cause the jerky motions of the loader, especially if air or moisture is in the valve/system. the check valves can also be jerky at lower engine RPMs due to when the system has enough pressure to open the valve, the pressure drops due to the volume being sent through the valve. it makes the valve turn on and off real fast.

Have you had the fill cap off how can the trapped air escape from the system

Most likely you have a leak in the suction tube where it passes between the hydraulic reservoir and the transmission. I think you should be able to access it by removing the plate under the seat that has the two tubes attached to it. The plate under the hydraulic reservoir has the lower part of the pick up tube attached to it. There is a seal between the upper and lower part of the suction tube. I believe it is just an O-ring but I have not had mine apart to be sure. A hole worn in the suction tube above the oil level will also allow air to enter but not necessarily leak oil.

Another place where air could enter is the gasket on the filter cap. Of that is bad they will usually also leak oil when the pump is not running.

(quoted from post at 14:12:29 11/27/16) Most likely you have a leak in the suction tube where it passes between the hydraulic reservoir and the transmission. I think you should be able to access it by removing the plate under the seat that has the two tubes attached to it. The plate under the hydraulic reservoir has the lower part of the pick up tube attached to it. There is a seal between the upper and lower part of the suction tube. I believe it is just an O-ring but I have not had mine apart to be sure. A hole worn in the suction tube above the oil level will also allow air to enter but not necessarily leak oil.

Another place where air could enter is the gasket on the filter cap. Of that is bad they will usually also leak oil when the pump is not running.

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I had all that apart, cleaned it all, new o-ring etc.

It has 99% new oil in it, as there was still some left in the loader control valve and a few hard lines I didn't remove. I replaced all the rubber hose except one piece close to the main hyd pump that is connected to the timing gears, as I could not get that off without removal of the hood, gas tank, etc.

I may have to make a video to show the problem, it's kind of hard to describe in words correctly.

It seems like it's either pump cavitation (though I see no foam in the oil) or it is relief vales that intermittently pop off. Thing is, when I deadhead cylinders on the loader, I don't hear the same relief valve like squeal.

The loader is basically unusable, it too jerky/erractic to be safe.

As far as the filler cap, it's an NPT plug, there is no gasket. It's definitely cranked tight. I did run it some more and yes, some air pressure was building up inside the trans housing. I could crack the plug loose an hear hissing only after running the loader boom up and down a few times.

I started a thread at TractorByNet on this issue if anyone uses that forum as well.

http://www.tractorbynet.com/forums/hydraulics/372473-ih444-ih2000u1111-loader-unsafe-jerky.html

It's a bit more descriptive of the work I did and where I am "stuck".