M4900 Hydraulic Problems. Power steering, PTO are OK. Everything else weak

[BAP]

SA cylinders work fine with SA valves.

Problems arise when you skirt the rules and try to use a DA valve to control a SA cylinder.

Dan

Then how do the hundreds of thousands farm tractors with planters and mowers with single action lift cylinders and dual valves work then? We used them for 40+ years without any issues.

 

[TheOldHokie]

Then how do the hundreds of thousands farm tractors with planters and mowers with single action lift cylinders and dual valves work then? We used them for 40+ years without any issues.

Just as you described earlier - with issues.

Dan

 

[wheelinag]

Well I wish it was as easy as the remote being stuck in one of the positions, but if I accidentally do that, I can hear it. The mower is no longer hooked up and hence the one hydraulic hose isn't either. No changes.

My buddy apparently did a mess of research while I was trying to manage the Johnson grass yesterday. He got a bunch of diagrams and trouble shooting lists. I'll start trying to trouble shoot this better tomorrow. I'm hoping it's just a piece of junk stuck in a relief valve somewhere.

Luckily I had brought the trailer to the orchard and it was supposed to be going back empty.

 

[TheOldHokie]

Well I wish it was as easy as the remote being stuck in one of the positions, but if I accidentally do that, I can hear it. The mower is no longer hooked up and hence the one hydraulic hose isn't either. No changes.

My buddy apparently did a mess of research while I was trying to manage the Johnson grass yesterday. He got a bunch of diagrams and trouble shooting lists. I'll start trying to trouble shoot this better tomorrow. I'm hoping it's just a piece of junk stuck in a relief valve somewhere.

Luckily I had brought the trailer to the orchard and it was supposed to be going back empty.

The neutral circuit on ypur tractor is quite simple.

Pump -> loader valve -> system relief valve -> remotes -> 3pt.

I dont see anyway a stuck relief will give you the symptoms you have.

Dan

 

[wheelinag]

The neutral circuit on ypur tractor is quite simple.

Pump -> loader valve -> system relief valve -> remotes -> 3pt.

I dont see anyway a stuck relief will give you the symptoms you have.

Dan

Any suggestions?

 

[TheOldHokie]

Any suggestions?

I am sorry - got this thread confused with another so I would like to retract the relief valve comment

Finding the problem should be straight forward. Start with pressure tests at the loader valve power beyond port.

1. Remove the power bryond hose and connect the gauge to the power beyond port on the valve. Start tractor and read pressure. That will be max pump pressure as regulated by the loader relief. If its low the problem is loader relief or pump
2. If pressure is good remove gauge and install a tee in the power beyind port. Connect gauge and power beyond hose to tee. Start tractor and read pressure. It should be close to zero. If not something downstream of the loader is blocking the neutral circuit.

Dan

 

[Russell King]

@wheelinag

You will need to know what type of threads are in the valve ports and then get adapters as needed for the tee and the gauge OR get the gauge and tee to match the port threads.

The gauge should probably be 3000 PSI to 5000 PSI maximum reading.

And the power beyond port probably has a power beyond sleeve in it that must stay in the port. That means the first hex head should be left in the valve (if there are two things that look like fittings).

 

[TheOldHokie]

@wheelinag

You will need to know what type of threads are in the valve ports and then get adapters as needed for the tee and the gauge OR get the gauge and tee to match the port threads.

The gauge should probably be 3000 PSI to 5000 PSI maximum reading.

And the power beyond port probably has a power beyond sleeve in it that must stay in the port. That means the first hex head should be left in the valve (if there are two things that look like fittings).

Same threads and connection point as the power beyond hose. Probably a female JIC-8 or -10 swivel.

Dan

 

[wheelinag]

Same threads and connection point as the power beyond hose. Probably a female JIC-8 or -10 swivel.

Dan

Thanks everyone for the suggestions and help.

We have a lot of hydraulic fittings here at the shop. I'm going confirm we have the right fittings, and if not order them this afternoon. I need to go to Tractor supply and buy quick connect as well. I left all of that kind of stuff at the orchard.

 

[TheOldHokie]

Thanks everyone for the suggestions and help.

We have a lot of hydraulic fittings here at the shop. I'm going confirm we have the right fittings, and if not order them this afternoon. I need to go to Tractor supply and buy quick connect as well. I left all of that kind of stuff at the orchard.

This type tee and a JIC cap will let you hook in for both tests with minimal changeover.

 

[wheelinag]

Well I think it took an hour to find all the fittings, but I came up with this Rube Goldberg. Gauge read 700psi on the power beyond port at 2300rpm. I'm going to check it with an analog tomorrow, but don't really have any suspicion that the digital gauge is wrong. I didn't have much more time today other than to get that reading.

Assuming it's correct, the issue seems to be either in the loader block/relief valve or the pump. I don't see how a pump dies in the middle of mowing a field, but I guess stranger things have happened.

I'm going to do some research tonight, but if anyone has the adjustment/test procedure for the relief valve, I'd appreciate it.

 

[wheelinag]

Hmm, this thread from 10 years ago has me concerned about what port is the power beyond. https://www.tractorbynet.com/forums...yond-line-hose-installation-to-loader.323149/

I have the manual that came with the loader from the original owner. It's labeled differently than the pics in the post above, even though it looks like it's the same valve block. Definitely double checking tomorrow when I get to the shop.

Edit: Found this snippet from another thread. This confirms what my manual shows, however, I think a few people mentioned it's the port with the "extra nut". There definitely was a port on the side of the valve block that had a stacked nut on it. I'll look where it goes on the tractor tomorrow.

 

[TheOldHokie]

Hmm, this thread from 10 years ago has me concerned about what port is the power beyond. https://www.tractorbynet.com/forums...yond-line-hose-installation-to-loader.323149/

I have the manual that came with the loader from the original owner. It's labeled differently than the pics in the post above, even though it looks like it's the same valve block. Definitely double checking tomorrow when I get to the shop.

Edit: Found this snippet from another thread. This confirms what my manual shows, however, I think a few people mentioned it's the port with the "extra nut". There definitely was a port on the side of the valve block that had a stacked nut on it. I'll look where it goes on the tractor tomorrow.

View attachment 154823

That was my immediate reaction.

What did you remove from that port before installing the swivel fitting? Put things back as they were originally and post some pictures of that.

Dan

 

[wheelinag]

The lines on my loader are hooked up exactly as in the manual that came the tractor from the previous owner. Attached are pictures of my loader and the pictures from the manual.

 

[TheOldHokie]

The lines on my loader are hooked up exactly as in the manual that came the tractor from the previous owner. Attached are pictures of my loader and the pictures from the manual.

Thats quite clear.

Disconnect the hose on the port labeled IN and connect your gauge to the hose. What pressure do you get there?

Dan

 

[wheelinag]

Well the "In Hose" is reading the same as yesterdays reading at the power beyond, ~700psi. I'm going to take seat off and sheet metal so I can get to the rest of this crap easier.

 

[TheOldHokie]

Well the "In Hose" is reading the same as yesterdays reading at the power beyond, ~700psi. I'm going to take seat off and sheet metal so I can get to the rest of this crap easier.

If the IN hose is reading 700 PSI something is wrong upstream. That feed is coming straight from the pump and should be roughly 2700 PSI. Given the sudden nature of thr failure my first thought is the main relief is stuck open.

Dan

 

[wheelinag]

If the IN hose is reading 700 PSI something is wrong upstream. That feed is coming straight from the pump and should be roughly 2700 PSI. Given the sudden nature of thr failure my first thought is the main relief is stuck open.

Dan

Well crap. Took everything apart and lightly pressure washed all the dirt off. Took apart the relief valve and saw no smoking gun. Cleaned everything and reassembled with hydraulic fluid. Same situation.

Any suggestions? I just don't see how a pump would die that quick. The day before the issue I was lifting 1500lbs of fence panels off a trailer.

 

[TheOldHokie]

Well crap. Took everything apart and lightly pressure washed all the dirt off. Took apart the relief valve and saw no smoking gun. Cleaned everything and reassembled with hydraulic fluid. Same situation.

Any suggestions? I just don't see how a pump would die that quick. The day before the issue I was lifting 1500lbs of fence panels off a trailer.

I will second the "well crap". Are you sure you removed the relief valve and not the safety valve?

I am also of the same mind as you with regard to the pump. Just to be sure about your inlet pressure test. You removed the hose connected to the IN port and screwed the gauge DIRECTLY onto the end of the hose. No tees or branches?

Dan

 

[wheelinag]

I will second the "well crap". Are you sure you removed the relief valve and not the safety valve?

I am also of the same mind as you with regard to the pump. Just to be sure about your inlet pressure test. You removed the hose connected to the IN port and screwed the gauge DIRECTLY onto the end of the hose. No tees or branches?

Dan

About 99.9% sure. Here is valve I took out and inspected. And yes, I hooked the gauge directly to the hose.

Not sure where to go from here. Is there another relief valve in the 3pt system? I'm hesitant to mess with the pump because I think I'll just end up with the same result.