Allis 5040 slow Hydraulics

[ametcalf]

The 3 pt lift has been slow on our Allis for several years. I have had it to two different shops for other work and told both shops to fix it if they could. Neither shop did anything to improve the lift. I told my wife the other day that I was going to get a gauge and maybe with the help available here I can find out the problem and fix it myself.
I put a 5000# gauge on one of the remotes and this is what I got.
Idle 100 psi
1000 rpm 200 psi
1500 rpm 500 psi
2000 rpm 800 psi
2400 rpm 1000 psi
The manual says that the pump should put out 6.3 GPM at 2600 rpm and 2133 psi. I don't have an easy way to check the flow but it seems to me that what I need is a new hydraulic pump. I think I can get one online for $283 and plan to go ahead unless some one has a better idea.
Any and all advice is appreciated.
Thanks, A. Metcalf

 

[ametcalf]

The 3 pt lift has been slow on our Allis for several years. I have had it to two different shops for other work and told both shops to fix it if they could. Neither shop did anything to improve the lift. I told my wife the other day that I was going to get a gauge and maybe with the help available here I can find out the problem and fix it myself.
I put a 5000# gauge on one of the remotes and this is what I got.
Idle 100 psi
1000 rpm 200 psi
1500 rpm 500 psi
2000 rpm 800 psi
2400 rpm 1000 psi
The manual says that the pump should put out 6.3 GPM at 2600 rpm and 2133 psi. I don't have an easy way to check the flow but it seems to me that what I need is a new hydraulic pump. I think I can get one online for $283 and plan to go ahead unless some one has a better idea.
Any and all advice is appreciated.
Thanks, A. Metcalf

I copied this from a response J_J gave to someone who was having a hydraulic problem and I think it is good advice for my situation.

"Pump could be weak and not pumping the potential pressure.
The 3pt valve could be leaking.
Piston seals worn.
The relief valve could have some trash in it.
The safety valve might have some trash in it.

Does the 3pt try and leak down after the lift is raised?"

In my case the 3pt does not leak down. I think the problem is either with the relief valve or the pump. I don't see any way to tap into the hard line that goes from the pump to the hydraulic control valve under the seat where the relief valve is so I can put a pressure gauge on it.
I am not sure but I think my problem is either in the relief valve or the pump. Is there a way that I can tell which it is or do I just change one and if that doesn't help, change the other?

 

[Leejohn]

How did you hook onto your remote? Did you just plug it in? Do you have a loader? By your reading you are not dead heading to get the relief valve to open.

 

[ametcalf]

How did you hook onto your remote? Did you just plug it in? Do you have a loader? By your reading you are not dead heading to get the relief valve to open.

I appreciate your response, not only are the hydraulics weak on our tractor but hydraulic knowledge is weak in my head.

I use the up side of the remote to raise the lift on a dump wagon that I have. I put a male quick disconnect on a gauge and plugged it into that side of the remote and raised the lever as if I were trying to dump the wagon.

 

[MHarryE]

Based on the numbers it really looks like 1 of 2 of J J's items is your problem. The problem is likely to be either a bad relief or badly worn pump. Do you have any idea how to get to the relief valve on your tractor to check it out? This is where having a service manual really comes in handy. Have you changed your hydraulic oil and filter? If you have and if you still have the filter, it would be interesting to open the filter and check for material. I assume your pump is a gear pump with aluminum housing - if the pump is badly worn you will find aluminum housing particles in the filter media.

 

[Leejohn]

MHarryE is right. Find your main relief if you have one, if not it's in the 3pt valve or may be the rockshaft housing.

 

[ametcalf]

Based on the numbers it really looks like 1 of 2 of J J's items is your problem. The problem is likely to be either a bad relief or badly worn pump. Do you have any idea how to get to the relief valve on your tractor to check it out? This is where having a service manual really comes in handy. Have you changed your hydraulic oil and filter? If you have and if you still have the filter, it would be interesting to open the filter and check for material. I assume your pump is a gear pump with aluminum housing - if the pump is badly worn you will find aluminum housing particles in the filter media.

I have the operator's manual and the service manual and the relief valve is real easy to get to. I just don't know what I should be looking for when I take it apart. The filter is a metal screen type of filter and over the years I have changed fluid and cleaned the filter as well as having a shop change the fluid. I assumed that when they changed the fluid that they also checked the screen. I don't remember seeing great amounts of metal in the screen but I don't know about what the shop may have found. Communications is not their strong suit. The tractor is at least 30 years old and as far as I know the pump nor the relief valve have never been changed. I can't remember how many hours it had on it when I had the engine overhauled quite some time ago. When they overhauled the engine I had them put a fix tach and in now reads 3600 hours so my guess is the pump and relief valve have at least 5 or 6 thousand hours. I didn't know that the pumps had aluminum housings. With that in mind my guess is that there has been alot of wear with that many hours and the tractor probably deserves a new pump. I think I will pull the relief valve when I get a chance and see if there is anything obvious. If anyone has any suggestions of what I should be looking for I would appreciate their wisdom.
Thanks

 

[MHarryE]

Some relief valves can get a bit complicated but it is likely that on your tractor it is a direct acting relief which means a spring is acting on a poppet. Hydraulic pressure pushes on the poppet until it overcomes the spring pressure. The poppet will lift off its seat allowing oil to flow directly back to tank. If it is this type of relief, it can be as easy as disassembly and inspection to make sure nothing is caught in the relief and there is no wear on the seating surfaces. Then the trick is to get everything reassembled correctly and to the right pressure setting. You have a pressure gauge - the gauge and wrenches should be all you need to set the relief if you disassemble it, find a problem, and solve it. When I talked about cutting open a filter and checking the media for wear particles, I had in mind a spin-on type filter element with a pleated fiber media. With just a strainer, its not possible unless you find big chunks. If the oil is changed properly, it is warmed up and drained so all of the wear particles will be in suspension and go out in the drain bucket. I worked in Engineering for Allis-Chalmers from 1967 - 1989 but on combines. We used Cessna hydraulic pumps exclusively but I do not know if tractors also used Cessna. The Cessna gear pumps were a simple and robust pump but at 5,000+ hours with only a strainer for filtration, I would not be surprised to find the pump worn out. We used a paper filter on combines but even then we didn't figure on even a 5,000 hour life for our gear pumps.

 

[ametcalf]

MHarryE,
Thank you very much, you have been very helpful. This tractor was made in Romania so I am not sure where the hydraulic pump was made. If I am understanding the manual right, there is no adjustment for the relief valve. If it is out of specs you replace it. Here is what the trouble shooting section of the manual says:

"E. Poor lifting capacity, less than estimated. 1)Probable cause--Wrong pressure relief valve setting. Remedy--Replace it. 2)Probable cause--Low pump efficiency (normally accompanied by a considerable increase of the lifting time). Remedy--Test pump performance and overhaul it, if necessary.

My thinking now is that I will take out the relief valve and look it over and if there is nothing obvious that I can see I will put it back and replace the pump and see if that helps. I will let you know what happens.
Thanks again.
A Metcalf

 

[MHarryE]

I hadn't realized this is a tractor sourced in Romania until you mentioned it. Definitely not a Cessna, nor any other US built pump. I did find this comment from another person who owns a 5040:

Mine runs great and everything works however, I am having troubles finding parts (relief valve, fender, front grill). Does anyone have a good site for parts? v/r Marty

Interesting that this person is looking for a relief valve. Not sure if that indicates a common problem.

The statement you have from the service manual indicates a cartridge relief that is not adjustable and cannot be disassembled to clean and inspect, but you might be able to spot something unusual like a cracked part or piece of metal stuck in the valve. I'm a bit confused by the "overhaul" comment in the service manual. If it is a gear pump like I suspect, the solution is the one you mention - replace. That's what the major gear pump manufacturers I have worked with over the past 20 years, Bosch-Rexroth and Sauer-Danfoss have said. Pump output not up to specs, replace the pump.

 

[ametcalf]

The statement you have from the service manual indicates a cartridge relief that is not adjustable and cannot be disassembled to clean and inspect, but you might be able to spot something unusual like a cracked part or piece of metal stuck in the valve. I'm a bit confused by the "overhaul" comment in the service manual. If it is a gear pump like I suspect, the solution is the one you mention - replace. That's what the major gear pump manufacturers I have worked with over the past 20 years, Bosch-Rexroth and Sauer-Danfoss have said. Pump output not up to specs, replace the pump.

After collecting metric sockets, 1/2" rachet and two big breaker bars I headed to the barn to attack the relief valve. The type of head on the cartridge took an 11/16 open end and when I got braced to put my weight into it I almost collapsed. It came out very easily because it uses an o-ring for sealing. I couldn't see any problems either with the cartridge or by looking in the hole so I put it back together.
I called one place to order a pump and they decided they must not stock it any more but by that time it was 5:00 pm. I am going to try another place in the morning and hopefully get one on order. The service manual actually gives pretty clear instructions on how to overhaul the existing pump but I think that would be a mistake for me to try.
Thanks again for your interest in my problem. The reason I am anxious to get this fixed now is that I am digging some post holes for a friend and in order to lift the digger out of the ground I have to run the tractor wide open which means the digger is spinning much faster than I would like.

 

[ametcalf]

I ordered a hydraulic pump this morning, they said it will be shipped Monday and hopefully it will get here Wednesday
A Metcalf

 

[MHarryE]

Glad you could find a pump. During the last several years there has been a lot of mergers and acquisitions in European hydraulic suppliers and with each merger, the remaining company would combine pump models - meaning they quit producing product lines. Fortunately there are standard pump mountings. In fact this might have happened back in the late 70s/early 80s when your tractor was built. I see the pump displacement changed from 5.75 to 6.23 gpm.

 

[Wayne County Hose]

I ordered a hydraulic pump this morning, they said it will be shipped Monday and hopefully it will get here Wednesday
A Metcalf

Before you put the pump in try removing the suction strainer. It's in a large steel line that runs to the pump, I believe 3 or 4 bolts to take the cap off. Don't clean and install, just remove it and try the hydraulics.

 

[J_J]

My opinion on this is that you should have verified the pump was not capable of the pressure required. If you can't test it your self, take it to a hyd shop and have them test it for you to verify good or bad/weak, and get an estimate for the rebuild if possible.

When you install the new pump, you will have to have a complete circuit to test pressure. you install the new pump.

If something downstream was causing your loss of pressure, you may have replaced a good pump.

 

[ametcalf]

Glad you could find a pump. ................

Thanks, I hope I found the right pump. I'm not counting my chickens until it comes and I get to look it over.

Before you put the pump in try removing the suction strainer. It's in a large steel line that runs to the pump, I believe 3 or 4 bolts to take the cap off. Don't clean and install, just remove it and try the hydraulics.

I flushed the system, cleaned the strainer and put in new fluid last year (about 100 hours ago) but I didn't think about trying the system without the screen. I will do that tomorrow if I get time, if not I will certainly do it before I put the new pump on. Thanks for the advice.

My opinion on this is that you should have verified the pump was not capable of the pressure required. If you can't test it your self, take it to a hyd shop and have them test it for you to verify good or bad/weak, and get an estimate for the rebuild if possible.

When you install the new pump, you will have to have a complete circuit to test pressure. you install the new pump.

If something downstream was causing your loss of pressure, you may have replaced a good pump.

J_J, I was hoping you would respond, I have a lot of respect for your knowledge. I should have been more patient, I thought maybe you weren't interested in my problem. I did try to read many of your posts in trying to figure this thing out. I asked the shop where I bought the 5000# gauge about what they would charge to rebuild the pump and they couldn't give me a ball park figure within a couple of hundred dollars. They could only give me their shop rate and they didn't know if they could get the parts or not. I kind of resigned myself to the idea that I would have to pay for my own education on this. I figured I would start at the pump ($225) because I thought that was the most likely culprit and then go to the relief valve ($105) and hope that one of the two fixed it. I didn't know about taking the screen out and running the system like Wayne County Hose suggested, which I will do before I change the pump. If the screen doesn't work, I will call the shop again and see what they would charge me to check the pump.
Thank you for your interest.

 

[J_J]

I would recommend installing the gage in the IN port of the FEL, using a tee. Now, operate all the valves so the cyl are maxed out.

Lets us know the reading on the FEL valve , remote valve, and 3pt valve.

With the gage installed at the input to the FEL. you can check any part of the hyd system.

As far as flow, remove a pressure hose and place in a bucket, and activate that work port.

If you can get 1.5 GPM in 15 sec, then your pump is putting out 6.3 GPM's, and you probably will not see any pressure.

The best way to test the pumps is with a gage, flow meter, and needle valve with a relief valve in the setup. BY connecting this setup just after the pump, it will test the pump only.

If you take the pump to a hyd shop, they will do a pressure, flow and load test for about .5 hr of labor cost. Then you will know for sure. Have them write down the figures for the test. However if the pump test good, then you have to look elsewhere for the leakage.

 

[ametcalf]

I would recommend installing the gage in the IN port of the FEL, using a tee. Now, operate all the valves so the cyl are maxed out.

Lets us know the reading on the FEL valve , remote valve, and 3pt valve.

With the gage installed at the input to the FEL. you can check any part of the hyd system.

As far as flow, remove a pressure hose and place in a bucket, and activate that work port.

If you can get 1.5 GPM in 15 sec, then your pump is putting out 6.3 GPM's, and you probably will not see any pressure.

The best way to test the pumps is with a gage, flow meter, and needle valve with a relief valve in the setup. BY connecting this setup just after the pump, it will test the pump only.

If you take the pump to a hyd shop, they will do a pressure, flow and load test for about .5 hr of labor cost. Then you will know for sure. Have them write down the figures for the test. However if the pump test good, then you have to look elsewhere for the leakage.

Ok guys, here's todays summary:
I called the hydraulic shop and they said they didn't know if they could test it or not but it would cost between $70 and $100 if he can so I figured I would follow your advice and see where that goes.
J_J, I don't have a FEL on the 5040 but I do have a remote that goes to my dump wagon. I ordered the fittings so that I can plumb a tee into that line. I then went out to the barn and it took 37 seconds to lift the empty wagon at 2400 rpm and it took 27 seconds for the wagon to come back down. I then took the screen out as Wayne County Hose suggested and wow what a surprise. I put the pressure gauge on and the pressure went right up to 2500 at 2400 rpm. If you remember the most I could get out of it before was 1000 at 2400 rpm. I also got 1500 psi at 1000 rpm, and at anything over 1500 rpm it jumps right to 1600 psi and then slowly advances to 2200 to 2600 psi. I then hooked the wagon back up and it took 32 seconds @ 2400 rpm to raise the bed and 17 seconds for it to come down. I then put the screen back in thinking that my problem would return but it did not. The pressures were about the same as with the screen out and now it only took 28 seconds to raise the bed. I forgot to mention that anytime the gauge was installed, I could hear the relief valve bypassing which I never heard before. Next I took the QD off the remote hose and ran it into a jug for 20 seconds and got 2.5 qts in the 20 seconds @ 2400 rpm which comes out to 7.5 qts per min. with no back pressure. While on the subject of flow the cylinder on the wagon lift is 5 inches in diameter and the rod comes out 18 inches which if my math is right comes out to about 1.5 gallons which makes the flow to that cylinder about 3 gallons per minute. At first that bothered me that it wasn't faster but then I got to thinking that maybe there is some kind of restrictor in that cylinder that keeps it from going up too fast. While running the fluid into the jug I could see that it was milky with a lot of air bubbles in it so we drained the fluid out rinsed the resevoir with diesel fuel, put in new hydraulic fluid and ran it for a few minutes while exercising the 3 pt hitch and then shut it down and drained it out. I then refilled with new hydraulic fluid and everything seems to be working pretty well now. I ran out of time and the real test will come in the morning when I put the post hole digger on and see how it does with that. One problem that I now have is that the 3 pt hitch has about 6 inches of bounce to it without any weight on it. I assume this is because of air in the system. I hope it works its way out when I run it with some weight on it. I looked in the operator's and maintenance manuals and couldn't find how to bleed the air out of the 3 pt hitch and I did a search on this web site and googled it but couldn't find any help. Maybe I was using the wrong terms but I didn't have any luck. I am thinking that if I put weight on the 3 pt hitch and shut the tractor off with the hitch raised that maybe the air will bleed out. Any advise on this would be appreciated.
I plan to see if I can find a new screen just to be on the safe side.
Thanks again for all of the help.
A Metcalf

 

[J_J]

If there is any air in the system. then operating the valve will bleed the air out.

A new screen will certainly help.

Check the volume of the hose at the cyl and see if there is any restriction.

Your volume seems low. 20 sec should have pumped 2 gal at max speed.

What is the relief setting on your remote valve, and the 3pt valve. With no FEL, the 3pt relief valve was the PRV, but I am sure you put the remote before the 3pt valve, so essentially, you would set the remote valve 50 to 100 psi below the pump max pressure, and set the 3pt relief pressure the same.

If you have air bubbles in the fluid, you might have a suction leak.

 

[ametcalf]

If there is any air in the system. then operating the valve will bleed the air out.

A new screen will certainly help.

Check the volume of the hose at the cyl and see if there is any restriction.

Your volume seems low. 20 sec should have pumped 2 gal at max speed.

What is the relief setting on your remote valve, and the 3pt valve. With no FEL, the 3pt relief valve was the PRV, but I am sure you put the remote before the 3pt valve, so essentially, you would set the remote valve 50 to 100 psi below the pump max pressure, and set the 3pt relief pressure the same.

If you have air bubbles in the fluid, you might have a suction leak.

J_J, Don't you sleep?
I appreciate all your advice.
Once I take the QD off the hose that I ran into the bucket there is no restriction in the line. The hose has half inch fittings on it and I would guess it is a half inch hose. The remote had never been used in the 30 years we have owned the tractor until I got the dump wagon last summer. In order to use the dump wagon, I had to change the QD on the remote hose. When I took the old QD off I realized the fluid in the remote hoses had turned to gunk so I took them off and cleaned them out throughly so I know there is no restriction in them. You are right about the flow, I don't know what I was thinking. When I got 2.5 quarts I thought the flow was good not thinking that it should have been gallons instead of quarts. I am a little hesitant to run the system too much without the screen in it. We did this flow test with the old screen in the system. Once I get the new screen we will try it again before I change the pump. I think when I install the new screen I should should take the whole line off between the bottom of the transmission and the pump and change all the o-rings and such to make sure we aren't getting any suction leaks.

As near as I can tell there is no way to set the remote pressure relief valve. It is a cartrige type afair that just screws out. The book says when there is a problem with it that it should be changed. I didn't realize until this morning that there are separate PRVs for the 3 pt hitch and the remote. I now see them in the book. The one I took out before was the one for the remote. Next time I go to the barn, I will try and find the one for the 3 pt hitch. You are right the remote does come before the 3 pt hitch. The book says the relief on the 3pt should be between 2062 psi and 2205 psi and the remote should be between 2133 psi and 2489 psi. It tells how to test the remote on the tractor but I can't find how to test the relief on the 3 pt hitch while it is on the tractor. The way I see it, if the 3 pt. hitch will lift what I need (the PHD) without engaging the relief valve it will be OK.
Well I am going to order the screen now and then go see how fast it lifts the PHD. Thanks again.