M125x hard power steering at low rpm

[Farmer-j]

Hi folks, looking for some advice on an ongoing issue i’ve been trying to diagnose

First off, a bit of background info

New to me M125x, almost immediately after getting it home it started having issues going into gear. When I went to shift into gear, tractor would beep and read “P” on dash. After doing some research I came to the conclusion that I was dealing with low hydraulic pressure issues. This problem seemed intermittent, occasionally tractor would start and go into gear and other times nothing but the flashing “P” on dash and tractor would not move.

Decided to disconnect discharge line off the power steering/ transmission pump and found that the pump wasn’t picking up suction. I checked that oil level was proper and installed new filters, inspected suction line and found no isssues. Problem still persisted so I ordered new pump and installed. Once new pump was installed, I drained and replaced oil and new filters once again. Started tractor and had flow at pump discharge, so reassembled everything and tractor has been going into gear without problems since.

However, since replacing the pump, I’m now having issues with hard power steering at low rpm once warmed up. When tractor is started cold the power steering seems to work fine and will turn with or without load on front end loader but after 5-10 minutes steering becomes hard and I need to increase engine rpm for steering to work.

I read through my WSM manual and it tells me to check pressures at regulator valve. I installed pressure gauge into the top check port and pressure is 310psi @2000pm which h looks to be in spec. Installed pressure gauge into bottom check port and at idle pressure is 130 psi and increases to 360 psi as I increase rpm to 2000rpm. According to the WSM this is low so I tried adjusting using the adjustment screw, as I adjust screw in (Clockwise) pressure decreases… this is opposite to what the wsm says should happen. Backed out and tried several times with same result. Decided maybe I have a regulator valve issues so I removed the valve and disassembled to check for stuck valve/ broken spring. Did not find any issues with the valve, everything seems to move freely and springs are good. Reassembled and installed back on tractor. Started tractor and again same issues, hard steering at low rmp when tractor is warm. Pressure is still low at regulating valve and will not increase as I screw in adjustment screw

Seems like the initial problem is solved but Any advice on what to look at next with tbhe power steering????

Questions

• Is it normal to see pressure fluctuate from 130- 360 as engine rev increases or should this be more static?
• What would cause the pressure to decrease as adjustment screw is turned in (clockwise)
• Is there any internal suction screen inside transmission that could be causing me issues?
• What should I look at next

 

[eserv]

Hi folks, looking for some advice on an ongoing issue i’ve been trying to diagnose

First off, a bit of background info

New to me M125x, almost immediately after getting it home it started having issues going into gear. When I went to shift into gear, tractor would beep and read “P” on dash. After doing some research I came to the conclusion that I was dealing with low hydraulic pressure issues. This problem seemed intermittent, occasionally tractor would start and go into gear and other times nothing but the flashing “P” on dash and tractor would not move.

Decided to disconnect discharge line off the power steering/ transmission pump and found that the pump wasn’t picking up suction. I checked that oil level was proper and installed new filters, inspected suction line and found no isssues. Problem still persisted so I ordered new pump and installed. Once new pump was installed, I drained and replaced oil and new filters once again. Started tractor and had flow at pump discharge, so reassembled everything and tractor has been going into gear without problems since.

However, since replacing the pump, I’m now having issues with hard power steering at low rpm once warmed up. When tractor is started cold the power steering seems to work fine and will turn with or without load on front end loader but after 5-10 minutes steering becomes hard and I need to increase engine rpm for steering to work.

I read through my WSM manual and it tells me to check pressures at regulator valve. I installed pressure gauge into the top check port and pressure is 310psi @2000pm which h looks to be in spec. Installed pressure gauge into bottom check port and at idle pressure is 130 psi and increases to 360 psi as I increase rpm to 2000rpm. According to the WSM this is low so I tried adjusting using the adjustment screw, as I adjust screw in (Clockwise) pressure decreases… this is opposite to what the wsm says should happen. Backed out and tried several times with same result. Decided maybe I have a regulator valve issues so I removed the valve and disassembled to check for stuck valve/ broken spring. Did not find any issues with the valve, everything seems to move freely and springs are good. Reassembled and installed back on tractor. Started tractor and again same issues, hard steering at low rmp when tractor is warm. Pressure is still low at regulating valve and will not increase as I screw in adjustment screw

Seems like the initial problem is solved but Any advice on what to look at next with tbhe power steering????

Questions

• Is it normal to see pressure fluctuate from 130- 360 as engine rev increases or should this be more static?
• What would cause the pressure to decrease as adjustment screw is turned in (clockwise)
• Is there any internal suction screen inside transmission that could be causing me issues?
• What should I look at next

Pretty normal for a 135 to have hard steering with a loader when you are not moving.

 

[North Idaho Wolfman]

Pretty normal for a 135 to have hard steering with a loader when you are not moving.

Did you mean 125?

 

[North Idaho Wolfman]

Hi folks, looking for some advice on an ongoing issue i’ve been trying to diagnose

First off, a bit of background info

New to me M125x, almost immediately after getting it home it started having issues going into gear. When I went to shift into gear, tractor would beep and read “P” on dash. After doing some research I came to the conclusion that I was dealing with low hydraulic pressure issues. This problem seemed intermittent, occasionally tractor would start and go into gear and other times nothing but the flashing “P” on dash and tractor would not move.

Decided to disconnect discharge line off the power steering/ transmission pump and found that the pump wasn’t picking up suction. I checked that oil level was proper and installed new filters, inspected suction line and found no isssues. Problem still persisted so I ordered new pump and installed. Once new pump was installed, I drained and replaced oil and new filters once again. Started tractor and had flow at pump discharge, so reassembled everything and tractor has been going into gear without problems since.

However, since replacing the pump, I’m now having issues with hard power steering at low rpm once warmed up. When tractor is started cold the power steering seems to work fine and will turn with or without load on front end loader but after 5-10 minutes steering becomes hard and I need to increase engine rpm for steering to work.

I read through my WSM manual and it tells me to check pressures at regulator valve. I installed pressure gauge into the top check port and pressure is 310psi @2000pm which h looks to be in spec. Installed pressure gauge into bottom check port and at idle pressure is 130 psi and increases to 360 psi as I increase rpm to 2000rpm. According to the WSM this is low so I tried adjusting using the adjustment screw, as I adjust screw in (Clockwise) pressure decreases… this is opposite to what the wsm says should happen. Backed out and tried several times with same result. Decided maybe I have a regulator valve issues so I removed the valve and disassembled to check for stuck valve/ broken spring. Did not find any issues with the valve, everything seems to move freely and springs are good. Reassembled and installed back on tractor. Started tractor and again same issues, hard steering at low rmp when tractor is warm. Pressure is still low at regulating valve and will not increase as I screw in adjustment screw

Seems like the initial problem is solved but Any advice on what to look at next with tbhe power steering????

Questions

• Is it normal to see pressure fluctuate from 130- 360 as engine rev increases or should this be more static?
• What would cause the pressure to decrease as adjustment screw is turned in (clockwise)
• Is there any internal suction screen inside transmission that could be causing me issues?
• What should I look at next

Do you have the WSM (aka service manual)?

 

[eserv]

Did you mean 125?

Yes, I meant a 125, but the 135 would be the same. The shorter wheelbase 135 was worse

 

[eserv]

Yes, I meant a 125, but the 135 would be the same. The shorter wheelbase 135 was worse

This is made even worse if the front wheels are widened out ( they should not be for loader work!)

 

[Farmer-j]

Do you have the WSM (aka service manual)?

Yes I have a WSM. Biggest thing that is puzzling me is the why the pressure on the regulating valve check port decreases as i screw in the adjustment screw clockwise which is opposite to what the WSM the manual says should happen. I also cant get the pressure to go above 360 psi at full rpm. WSM says should be between 398-426 psi

 

[Farmer-j]

This is made even worse if the front wheels are widened out ( they should not be for loader work!)

I can understand having heavier steering at low RPM but this is basically no steering until rpm are above 1100 rpm.
Also doesn't make sense to me why it works perfectly fine when tractor is cold but stops as soon as oil heats up

 

[Farmer-j]

Do you have the WSM (aka service manual)?

Wolfman, can you provide any insight into what would cause the pressure on the regulator valve to decrease as I adjust the adjustment screw in clockwise? My pressures are low according to to the WSM

 

[North Idaho Wolfman]

Wolfman, can you provide any insight into what would cause the pressure on the regulator valve to decrease as I adjust the adjustment screw in clockwise? My pressures are low according to to the WSM

Have you tested all of the outputs of the regulator?

 

[Farmer-j]

Have you tested all of the outputs of the regulator?

Yes I have checked pressures. One the picture attached, Pressure on port #1 is 310psi (whithin spec) , pressure on port #3 is 360 psi ( Spec is 390-425 psi)

Port #3 is low but when i try to increase pressure as WSM describes by turning sdjustment clockwise then my pressure decreases. Can't get pressure to go above 360 psi

 

[North Idaho Wolfman]

Yes I have checked pressures. One the picture attached, Pressure on port #1 is 310psi (whithin spec) , pressure on port #3 is 360 psi ( Spec is 390-425 psi)

Port #3 is low but when i try to increase pressure as WSM describes by turning sdjustment clockwise then my pressure decreases. Can't get pressure to go above 360 psi

That's telling me that the max pressure that the pump / relief valve can supply is 360 psi.
I will dig into the main hydraulic system and see what else could be dropping pressure.

 

[Farmer-j]

That's telling me that the max pressure that the pump / relief valve can supply is 360 psi.
I will dig into the main hydraulic system and see what else could be dropping pressure.

Would this be the relief valve on the power steering gerotor that that controls the relief flow to port #3 on the regulator valve?

 

[North Idaho Wolfman]

Would this be the relief valve on the power steering gerotor that that controls the relief flow to port #3 on the regulator valve?

Yes that could be one of the issues.

 

[Farmer-j]

Yes that could be one of the issues.

Tonight I installed pressure gauge on steering motor to test bypass pressure. At idle bypass pressure with steering wheel turned fully to the left is ~1500 psi, increased rpm to 2100 and bypass pressure increased to 2100 psi.

Would this be normal to see this much variance between idle and full rpm on this relief valve?
Is there another relive valve for this pump?

 

[TheOldHokie]

Tonight I installed pressure gauge on steering motor to test bypass pressure. At idle bypass pressure with steering wheel turned fully to the left is ~1500 psi, increased rpm to 2100 and bypass pressure increased to 2100 psi.

Would this be normal to see this much variance between idle and full rpm on this relief valve?
Is there another relive valve for this pump?

Your low RPM pressure loss is caused by leakage somewhere.

It could be the relief is not fully closing or the pump is worn and leaking internally.

There msy be other explanations. Where was the gauge connected and how?

Dan

 

[Farmer-j]

Your low RPM pressure loss is caused by leakage somewhere.

It could be the relief is not fully closing or the pump is worn and leaking internally.

There msy be other explanations. Where was the gauge connected and how?

Dan

Guage was tee'd in on the "L" port on steering motor (outlet to steering cylinder), steering wheel turned all the way to the left and recorder pressure at idle and at full rpm. Pressures were low so i sourced another steering motor form neighbour. I installed the spare steering motor and checked pressures, reading basically exact same as my original one. 1500 psi at idle and 2100psi at max rpm. Doesn't seem this the relief valve is the problem.

The hydraulic pump is brand new, new kubota oil and filters as well

 

[Farmer-j]

Your low RPM pressure loss is caused by leakage somewhere.

It could be the relief is not fully closing or the pump is worn and leaking internally.

There msy be other explanations. Where was the gauge connected and how?

Dan

Curious what your thoughts are on other possible explainations, starting to run out of ideas what other things I can test

 

[TheOldHokie]

Guage was tee'd in on the "L" port on steering motor (outlet to steering cylinder), steering wheel turned all the way to the left and recorder pressure at idle and at full rpm. Pressures were low so i sourced another steering motor form neighbour. I installed the spare steering motor and checked pressures, reading basically exact same as my original one. 1500 psi at idle and 2100psi at max rpm. Doesn't seem this the relief valve is the problem.

The hydraulic pump is brand new, new kubota oil and filters as well

CAUTION: this advice assumes there is a relief in or somewhere upstream of the steering motor. I do not have a WSM for thIs tractor so verify before attempting this test

Ditch the tee and connect gauge directly to L port. As soon as you turn the wheel left the port pressure will max out against the relief valve. Only hold the wheel left long enough to get a pressure reading. This number is the relief valve cracking pressure.

If the number you get with this test is higher than the previous numbers you are leaking pressure downstream of the steering motor.

Dan

 

[Farmer-j]

Is anybody able to explain the fluid flow through the this entire circuit? Hydraulic pump discharge ties directly to the top of the regulator valve but I don't fully understand how the fluid flows through the different spools within this regulator valve to end up at the steeering motor. Understanding this flow would really help me identfy where the problem might be