Ford 4000, 3pt not working under load

I am trying to troubleshoot my 3 pt. It does not work under a load. I put a new hydaulic pump in a couple of years ago and it worked for one season. Arms will come up with out load. Local NH dealer said it was probally the flow control valve and that they would sell me one for around $1,000. Looking for other ideas before I go to that extreme.

Is that an earlier 4 cylinder 4000 model, or a later 3 cylinder 4000 model?

Since you mentioned a flow control valve, I assume that it is the later 3 cylinder model, since I don't believe that the 4 cylinder models had a flow control valve.

Has the dealer actually looked at the tractor, or are they just going by your description of the problem?

The flow control valve controls the speed of the flow of the fluid, but not the pressure or how strong it can lift, so I personally would doubt it being the flow control valve. If it allows enough fluid to flow to lift the arms with no weight on them it should allow enough to flow to lift them with a load as well. It sounds more like the relief valve is leaking or opening too soon to me.

Sean in PA,

Thank you for your reply. No the dealer has not looked at it. and yes you are correct in your deduction that it is a 3 cy dsl. How do you go about checking and/or fixing the relief valve?

Yes, Untill we get to know you here -or at least get to know your tractor - always mention if it is a 3 or 4 cyl model.
Your dealer sounds like he's full of hooey.
Put a test gauge on it somewhere and check the pressure - either on a remote hose or if you don't have remotes hook it to the test port on the blank cover under the seat - first photo.
Just as you can not see what your electrics without a meter you can not see your hydraulic pressure without a gauge. Cheap gauge can be had from Northerntool or ebay.
Post back with your findings. Someone here can surely help you.

I finally got the tractor running (the starter was bad) to be able to test as you suggested.
I first attached the guage to the remote and the gauge did not register a pressure, but the arms did come up.
Today I attached the guage to the plate under the seat identified in you picture. Again the pressure did not register. I reved the engine just to see if that made a difference. Although the arms came up faster it did not make a difference on the guage.
There was pressure, apparently not enough to register on the guage . I know because I did not let the arms back down before disconnecting the gauge and as I removed the gauge the fluid shot out of the port and the arms went back down.

The guage came from the local Ford dealer and looks just like the one in your photo.

Where do I go from here? Thank you for you input.

That test port will only show pressure if you do something to provide resistance to the flow. Hydraulic flow without any resistance equals no pressure. Only flow and resistance combined produces pressure. You can try lifting whatever heavy implement it is that you said it wouldn't lift in your original post and watch the gauge while you try that. You should see at least a little pressure build up before the relief valve opens and dumps the pressure. However, if it won't even lift a hundred pounds then you likely won't be able to see the pressure on a 3000 psi gauge.

(quoted from post at 10:09:32 05/10/13) That test port will only show pressure if you do something to provide resistance to the flow. Hydraulic flow without any resistance equals no pressure. Only flow and resistance combined produces pressure. You can try lifting whatever heavy implement it is that you said it wouldn't lift in your original post and watch the gauge while you try that. You should see at least a little pressure build up before the relief valve opens and dumps the pressure. However, if it won't even lift a hundred pounds then you likely won't be able to see the pressure on a 3000 psi gauge.

Click to expand...

Okay. And if I don't see pressure, then what? Sorry, all very new to this.

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(quoted from post at 04:14:56 05/11/13) [u:6e70a10c14]Hydraulic top cover Repair Kit[/u:6e70a10c14]

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Click to expand...

Thank you very much.

I have replaced the o-rings including the big one on the lift cylinder and once I got everything put back the arms came up quickly and was able to lift about 200 lbs so I thought eveything was good. Next I attached the brush hog and was only able to lift it about six inches off the ground. So I still do not have the lift power I should have. This is what I am going to try next:
1. Confirm fluid level.
2. Put gauge on to see if any pressure now shows.
(It did not show any pressure before.)

Can someone suggest additional things to check or try?

Lets go back to square one. Its been a long time but it won't hurt to start there. Three years ago you installed a new pump. Why? What were the symptoms and how did you know it needed a new pump. Was the pump new or rebuilt.

I'm wondering if you're sucking air somewhere but that's a solution before confirmed symptom. You might start by testing the pressure at the pump now that you have a gauge.

(quoted from post at 07:37:34 05/26/13) Lets go back to square one. Its been a long time but it won't hurt to start there. Three years ago you installed a new pump. Why? What were the symptoms and how did you know it needed a new pump. Was the pump new or rebuilt.

I'm wondering if you're sucking air somewhere but that's a solution before confirmed symptom. You might start by testing the pressure at the pump now that you have a gauge.

Click to expand...

The symptoms three years ago were much the same as they are now. After installing an aftermarket remote (six years ago) to be able to raise the hay mower all was fine for about three years. Then the hydraulics began to fail. I checked fluid levels, they were fine. After speaking with dealer at that time and not knowing any better I deduced it was the pump and purcased an aftermarket one via the internet since it was roughly half of what Ford dealer wanted. A machanic friend of mine helped me install it. (Incidently, the original pump did not show a significant amount of wear and I still have it. Afterwards the hydraulics worked for a season but leaked from the top of the pump where the tube goes up to the flow control valve. When I addressed this it looked like my friend had left off one of the o-rings on that tube. So I installed one and everything was good as we began hay season. By the end of the season though we were back to hydraulic failure. I bought Ford fluids because the dealer told me the generic brand could be the source of the problem. Changing fluid did nothing really to improve the condition. The last two years I have just done without hydraulics on this tractor. Im tired of it not working the way it should. I don't have money to take it to the dealer though. I will put the guage on it tomorrow ( I had to work today) to see if I get a reading. I didn't get a reading before replacing the o-rings.
Not sure where I would be sucking air from if that could be the issue.

Thanks for your reply!

Sorry. I didn't have more time to respond to your last post. It sounds like your 4000 has the gear pump in the center housing. There should be a pressure port in the face of the pump. You can connect a test line to this pressure tap. Unfortunately you're going to need more than just a pressure gauge. You need a high pressure line to tap the pump. On the other side of the high pressure line you install a Tee and pressure gauge. You then exit the Tee with another high pressure line and run it to a high pressure valve. This is called a load valve and it enables you to restrict the flow of high pressure oil through your test line which places a load on the pump and registers pressure on the gauge. You run a low pressure line out the other side of the load valve back to the fill plug in the center housing so the oil circulates out of the pump and back into the hydraulic system.

McMaster Carr is one source for a high pressure valve.

As you close the valve, the pressure rises in the test line and hydraulic system and registers pressure on your gauge. If you close the valve completely, the relief valve in the pump should open and allow oil to flow back into the center housing and you should register maximum pressure on your gauge.

I'm curious. Do you still have all the parts which would enable you to block off the remote valve you installed. If you could quickly remove the remote and return the tractor to its original configuration and it functioned normally, you'd have your problem isolated. If this produced no change, you'd know the problem was not in the remote valve.

I think you can troubleshoot this yourself and figure out what's going on. It doesn't sound like the dealer was much help to you. Selling you more parts you don't need or charging you to repair a problem they don't know how to fix isn't going to help your checkbook. You've had the top cover off and the pump out so there's no more mysteries.

You really need a manual. I think someone suggested this already. I may be able to scan and email the pages which will be helpful to you if you wish. The Ford manual isn't easy to flatten out on a scanner. I'm not sure how email works on this forum. I will have to figure that out.

Hope this helps a bit and doesn't make things worse.

Sorry, I can't seem to post my entire response. I tried breaking it up into several posts but only the first part posts as an edit. I'll try again later.

Found the problem. The URL to McMaster Carr. Here it is without the link.

http://www.mcmaster.com/#flow-control-needle-valves/=mxvv0t

(quoted from post at 21:19:05 05/27/13) I think you can troubleshoot this yourself and figure out what's going on. It doesn't sound like the dealer was much help to you. Selling you more parts you don't need or charging you to repair a problem they don't know how to fix isn't going to help your checkbook. You've had the top cover off and the pump out so there's no more mysteries.

You really need a manual. I think someone suggested this already. I may be able to scan and email the pages which will be helpful to you if you wish. The Ford manual isn't easy to flatten out on a scanner. I'm not sure how email works on this forum. I will have to figure that out.

Hope this helps a bit and doesn't make things worse.

Click to expand...

Thank you for your response. I did get a manual. Two actually. The second one seems to be much better than the first when it comes to diagnosing the hydraulics. I will be getting the valve and hose you reccomended and will post results when I have completed that test.
I have a question. If the pump proves to be the issue. Can the old one I have be rebuilt or will I be better off getting a new one.

I did have a couple successes. I fixed the headlights on the 4000 yesterday. That was a bad wire and blown fuse. And, we test drove the 2000 after replacing the front axle and associated parts.

Thanks again!

I don't think you're going to find that the pump is the problem. If you tell me you've been operating the tractor and the pump has been making a high pitched whining noise when running or when you put a load on it I'd change my mind. You haven't said anything that sounds like your pump has been cavitating for quite some time. Cavitation is caused by air being drawn through the pump which will eventually destroy the pump.

Your pump body is not rebuildable using any methods you and I have on hand. If the bushings (bearings) wear and the gears start running out of allignment, they will touch the pump body and eat it up. The pump body is not replaceable. If the bushings (bearings) wear a little but the gears and pump body are good, the bushings and seals were replaceable at one time. If seals were readily available, I'd tell you to take the old pump apart and see what it looks like inside. I'd bet it looks good. Probably better to leave that for another day and just figure out what's going on now so you can use the tractor instead of work on it.

Your dealer didn't steer you completely wrong. There is a valve spool in your flow control valve which can stick, causing the fluid to dump back into the center housing. You can check this valve spool from the outside by pulling the bolt/plug that seals the valve body and determining whether the valve spool moves in the bore. The first thing to come out after the plug is a spring. The valve is behind the spring.

You didn't mention that you had a parts book. You should be able to go online at Messicks and look at parts diagrams. A lot of mystery fades quickly away when you can see what you're working on.

I finally got the test hose and tested the pressure from the port on the face of the flow control valve assembly as well as removing the remote block and testing again. Following the proceedure in the manual I have. I brought the tractor up to approximately 1650 rpm. Fluid was moving through the hose but when I closed the valve the guage did not register any pressure until I throttled the engine fully and then the gauge showed 200 lbs. The result was the same when I removed the remote block. I have not taken the next step that book instructs which is to drain the fluid and pull the pressure relief valve and add shim(s). Manual also says that if adding shim does not change pressure then overhaul pump. Is there an overhaul kit available anymore? I do not believe Ford has one.

Something which may or may not be important is that when my mechanic friend replaced the pump for me he did not remove the pump suction tube and therefore that o-ring was not replaced.

I have wondered if the flow control valve could be the problem. Have considered that it was not installed correctly when the pump was replaced because I can screw it all the way out. Isn't there suposed to be a keeper to keep it from coming out?

Thank you for your replies!

Does your shop manual show a procedure for checking pressure at the pump.

If your pickup tube o-ring is above the oil level in your center housing you could be sucking air through the o-ring. If its below the oil level it may just suck oil but there's a possibility that its creating a void when sucking oil and pulling air in from the surface.

I have to check the parts book but I remember a circlip on the flow control valve spool that prevented it from backing out completely. Hopefully I'm not steering you wrong.

There is a dump valve in the flow control valve housing which can stick, causing oil to return to the center housing. You can check this valve spool from the outside of the flow control housing by pulling the plug that seals the dump valve bore. Check to see if the dump valve spool moves in the bore. Pull it out and look it over closely. The first thing to come out after the plug is a spring. The valve is behind the spring. If the dump valve is returning oil to the center housing you're not going to have much oil pressure.