Ford 3000 Hydraulic Sucking Air

[jascott]

Looking for some help on what I think is the hydraulic system sucking air. This is a 71 3000 which I have recently pulled the lift cover and replaced some seals, both hydraulic filters, and fixed a few parts here and there. The tractor is no longer leaking fluid, but I can't seem to get the hydraulic system to work well. It will raise and lower, but takes a full 20 - 25 seconds to raise the life completely. I have bled the system a bunch of times, and the fluid coming out appears to be a steady stream, but is milky full of air bubbles. The fluid is new, and I'm positive there is no water in it.

Where to start? I replaced the o-rings I could see, but I haven't tried to rebuild anything else.

What are some likely/common places to check for a bad connection? Is it fair to assume that I would see fluid leaking at a joint if it were able to suck air?

 

[Jerry/MT]

Looking for some help on what I think is the hydraulic system sucking air. This is a 71 3000 which I have recently pulled the lift cover and replaced some seals, both hydraulic filters, and fixed a few parts here and there. The tractor is no longer leaking fluid, but I can't seem to get the hydraulic system to work well. It will raise and lower, but takes a full 20 - 25 seconds to raise the life completely. I have bled the system a bunch of times, and the fluid coming out appears to be a steady stream, but is milky full of air bubbles. The fluid is new, and I'm positive there is no water in it.

Where to start? I replaced the o-rings I could see, but I haven't tried to rebuild anything else.

What are some likely/common places to check for a bad connection? Is it fair to assume that I would see fluid leaking at a joint if it were able to suck air?

First, let me say i don't know anything about the specifics of your tractor. Therw are, however, some things that are common to all tractor hydraulic systems.

The suction supply line to the pump is what I suspect. It's either loose, cracked or restricted in someway. A lot to time there is sludge in the sump that builds up over the years and blocks any screen or inlet to the pump. Clean the sump and check the suction pipe for a leak, a crack, or clogging.

 

[wdchyd]

X 2 what Jerry said.......

Empty hyd reservoir and clean out suction strainer (under tank).....then check over suction line and clamps real good (look inside carefully).....replace if in doubt....and last, the hyd pump shaft seal can suck air in (usually compounded by clogged suction screen/hose).......you won't be able to see this condition but you can fake it out by packing clean grease around the input shaft on the pump.......if the air bubbles goes away temporarily after start-up then you have air entrainment at the shaft seal......reseal it..:thumbsup:

 

[jascott]

Last year, I cleaned it all up, replaced a bunch of seals, etc. I also replaced both hydraulic filters. I've pulled the lift cover again and they are fine and the fluid is new, again.

There is a check valve seat in the front of the lift cover which I believe might be the problem. I was able to pull the check ball and spring out, but the seat seems to be stuck/siezed into the lift cover. I messed around with all this and put it back and now even with the system bled, I get absolutely no movement of the lift.

Problem is I have no idea how to get the check valve seat out? Maybe drill it? I'll see if NH can order a new check valve seat.

So tired of messing with this thing. Anybody wanna buy a 71 3000 in Dallas?

 

[whodat526]

pull the bleader screw out the pump then drive it head first into a ditch and see what happens (that is what is always do) them tractors or hard to bleed the hyds.

 

[Jbrink64]

Last year, I cleaned it all up, replaced a bunch of seals, etc. I also replaced both hydraulic filters. I've pulled the lift cover again and they are fine and the fluid is new, again.

There is a check valve seat in the front of the lift cover which I believe might be the problem. I was able to pull the check ball and spring out, but the seat seems to be stuck/siezed into the lift cover. I messed around with all this and put it back and now even with the system bled, I get absolutely no movement of the lift.

Problem is I have no idea how to get the check valve seat out? Maybe drill it? I'll see if NH can order a new check valve seat.

So tired of messing with this thing. Anybody wanna buy a 71 3000 in Dallas?

The check valve wouldn't allow air into the system. It would affect lift power and holding ability. To remove the seat, Ford made a tool to remove it.

I will assume you have the engine mounted, cam driven pump. If so, air ingress could be from a small crack in the suction tube, the orings at each end of the tube, or, the shaft seal inside the pump.

 

[Soundguy]

hardline suction side loose at the pump?

soundguy

 

[jascott]

It doesn't appear to be???

I did pull the lift cover again thinking I would go through the orings, etc and doublecheck a few things. I noticed a plug on the front which houses a check valve. I pulled this and the check valve spring housing, check valve ball, check valve spring and the check valve guide. There was no oring in between the check valve spring housing and check valve guide and I can not get either the check valve seat out of the lift cover. The o-ring between the check valve seat and the check valve spring housing was also missing. The check valve seat appears to be siezed into the lift pump cover.

I put it all back together and bled it again and now I can't even get the arms to lift at all. I did rebleed the system at the pump and I am getting fluid without air bubbles now. Does it sound like the check valve seat could be the entire problem?

 

[Jbrink64]

The check valve seat is pressed in, and requires a special tool to remove it. Unless the seat split lengthwise (not probable) it should not affect the lift. The check valve is there as a load check valve and makes controlling a heavy load more precise. Even with the ball removed, it will still lift.