New Holland 2120 dead headed pump

[MrTea]

This is concerning a 2000 New Holland 2120 compact tractor
I purchased the tractor with this problem so I have no back story or history on it. The tractor would not move forward or reverse so after a lot of investigating I found the power steering pump input shaft was sheared off. The transmission pump is piggyback to the steering pump so they both quit working.
This is potentially good news just one more thing... What caused the deadhead and how do I figure it out? It would be really bad to install a new pump only to have it last a few seconds. There were slivers of metal in the steering pump and wear on one side of the bore. I do not know if this indicates that the steering side was the problem side. The input shaft could have sheared from either pump deadheading.

A couple observations:
The manual says the steering should function even without the aid of the pump. The wheel is hard to turn and it tries but it doesn't steer. I imagine it may if I jacked the front tires off the ground. normal?

On the transmission side I wasn't getting power to the forward and reverse solenoids until I repaired a connection and reconnected a ground. This was off where someone else was trying to fix it. They had removed the control module. I don't know if running it with the control module not working could have caused the damage?

My tractor is a little different than the ones in my manuals. There is a pump mounted behind the timing cover that runs the loader etc.(the loader works fine) then in front of the timing cover are two pumps. The first is the steering pump and the second is the HSS transmission pump. They are bolted together with one input shaft.

 

[countrybumpkin]

What makes you think it had a dead head issue, could be that the pump locked up and broke the shaft.

 

[MrTea]

What makes you think it had a dead head issue, could be that the pump locked up and broke the shaft.

That could be but the pump looked nice or I should say no signs of getting hot. There were slivers off the teeth of the pump gears still in the pump where the gears dug into one side on the lower part. My guess was that it dead headed and the odd wear was from extreme pressure. The bushings and everything else seamed to be in very good shape. I can't be sure what happened though.
Here you can see the scoring and a large sliver:

Slivers on gear:

Output shaft:

 

[oldnslo]

Mrtea,
Since you have no history we can only guess but does it look like someone messed with the any of the plumbing exiting the pump? Reason for asking is that the first valve in the pressure line must be the relief valve. This can be in a block on the tractor, possibly in steering unit, or in front loader valve, etc. If some tried rerouting the plumbing they could have blocked the pump flow and then the weakest link breaks.

 

[RickB]

I would put compressed air (rubber tipped blow gun) into both pump pressure lines and make sure the circuits are open to sump before starting a new pump.

 

[MrTea]

Mrtea,
Since you have no history we can only guess but does it look like someone messed with the any of the plumbing exiting the pump? Reason for asking is that the first valve in the pressure line must be the relief valve. This can be in a block on the tractor, possibly in steering unit, or in front loader valve, etc. If some tried rerouting the plumbing they could have blocked the pump flow and then the weakest link breaks.

The plumbing has not been messed with that I can tell. There is a pretty good leak near where one of the lines goes into the steering ram. When I filled the power steering reservoir it leaked back down over the next couple days. Off the first pump there is a supply line and a pressure line that goes to the steering control valve. Off the second pump there is a supply hose and a pressure line that goes to the HSS transmission control valve.
I will double check all the routing of lines to make sure none seam out of place.

 

[MrTea]

I would put compressed air (rubber tipped blow gun) into both pump pressure lines and make sure the circuits are open to sump before starting a new pump.

That's a great idea. Is it safe for both the steering and transmission lines? Would it trigger the relief valves?

 

[RickB]

That's a great idea. Is it safe for both the steering and transmission lines? Would it trigger the relief valves?

Both circuits are open center and should discharge back to tank so long as the steering wheel is at rest and neither transmission solenoid is activated.

 

[MrTea]

Both circuits are open center and should discharge back to tank so long as the steering wheel is at rest and neither transmission solenoid is activated.

That will be an interesting test. I will get it done in the next day or 2.

Thanks

 

[MrTea]

The transmission circuit was clear but on the steering circuit I couldn't see any air getting through. I pulled the return line and nothing came out.

 

[RickB]

I’m concerned about that but uncertain how to advise you.

 

[ptsg]

Check the lines on the power steering valve. Could be that someone tried to rebuilt it and messed up the lines. There should be markings on the valve. A and B goes to the cylinder and P should go to pump and T to tank.

 

[MrTea]

Check the lines on the power steering valve. Could be that someone tried to rebuilt it and messed up the lines. There should be markings on the valve. A and B goes to the cylinder and P should go to pump and T to tank.

Will do thanks.

 

[MrTea]

I’m concerned about that but uncertain how to advise you.

I will verify the lines are in the correct locations as recommended by ptsg then look over the valve in the manual and see if there any clues.

Thanks

 

[MrTea]

Today I took the orbital valve(steering) apart and I may have found the problem. I also don't know what I am looking at really so I could be totally wrong.

Here is a drawing of the valve(I think it's the same)

The relief valve I took off my pump(follow number 2 on the drawing all the way to the left).This is the plug for the hole, the cap to adjust the spring or hold it in place and the spring. According to the drawing there is a piece missing. A plunger looking thing.

It looks like it could have been new or reman.

I put it back together because there was no reason to let it sit in pieces. Now air flows through from the pressure port out the return line. I guess I can put it back on the tractor and see if it steers now. Any other idea?

 

[MrTea]

This is what I think the relief valve looks like in mine. If there is a piece in the bottom of the hole(#3) it does not budge.

 

[mike48130]

I would put compressed air (rubber tipped blow gun) into both pump pressure lines and make sure the circuits are open to sump before starting a new pump.

I would not do this. If there are any particles in the lines, you just blew them into the rest of the system. Take off the lines and clean them. Take out the pressure relief and check it out and the cavity. Spray them all out with brake cleaner.

Put a gauge on the test port when you start it. I would back off the pressure relief so you know it is below spec, then reset it once running and safe. Some reliefs use a screw, some use shims to adjust. Could be set too high or damaged, so a good inspection or replace based on cost.

Check the hydraulic schematics, and check the relief port/tube/galley back to the tank. If that for some reason is blocked, the relief valve doesn't do any good, and won't relieve the pressure. That you can check with air since your tank has a filter on it.

 

[mike48130]

It looks like you are missing the plunger in the relief valve. If that were the case, you wouldn't get any steering even if the pump was working. You would just pump oil back to the tank. Any chance you dropped it by mistake? Could be a rebuilt that was rebuilt wrong.

 

[MrTea]

I would not do this. If there are any particles in the lines, you just blew them into the rest of the system. Take off the lines and clean them. Take out the pressure relief and check it out and the cavity. Spray them all out with brake cleaner.

Put a gauge on the test port when you start it. I would back off the pressure relief so you know it is below spec, then reset it once running and safe. Some reliefs use a screw, some use shims to adjust. Could be set too high or damaged, so a good inspection or replace based on cost.

Check the hydraulic schematics, and check the relief port/tube/galley back to the tank. If that for some reason is blocked, the relief valve doesn't do any good, and won't relieve the pressure. That you can check with air since your tank has a filter on it.

I already checked it with air pressure.
I checked the pressure with a gauge first. There wasn't any because the input shaft on the pump was sheared off.
The orbital valve was blocked.

 

[MrTea]

It looks like you are missing the plunger in the relief valve. If that were the case, you wouldn't get any steering even if the pump was working. You would just pump oil back to the tank. Any chance you dropped it by mistake? Could be a rebuilt that was rebuilt wrong.

I believe the plunger is missing, it would be nice to see a picture of one. I didn't drop it...
I went out to double check and found it on the ground. Dang it. Glad you asked, I had everything laid out as I pulled it apart.I thought there was zero chance I dropped it. Going to put it in and test it with air again.