M5140 Power Steering Issue

KD47

New member

Equipment
M5140
Nov 1, 2020
3
0
1
Alabama
I have an M5140 with only 250 hours on it and the power steering does not work well any time I have more than a few hundred pounds of weight on the bucket (or moving 800 LB hay bales). I need to get this fixed but not sure what the exact fault is. Has anyone else experienced this? If so what did you do to fix it?
 

SidecarFlip

Banned

Equipment
M9000HDCC3, M9000HD, Kubota GS850 Sidekick
Oct 28, 2018
7,197
555
83
USA
No Kubota with hydrostatic steering works well when the motor is turning at low RPM, the fluid flow and pressure isn't high enough to efficiently turn the wheels right or left with any weight in the bucket..... (I'm presuming that is the issue as you are pretty vague about it).

One thing that helps is making sure your front tires are inflated to the MAXIMUM rated pressure listed in your owners manual. The more they squat the harder it is for them to turn sideways.
 

KD47

New member

Equipment
M5140
Nov 1, 2020
3
0
1
Alabama
No Kubota with hydrostatic steering works well when the motor is turning at low RPM, the fluid flow and pressure isn't high enough to efficiently turn the wheels right or left with any weight in the bucket..... (I'm presuming that is the issue as you are pretty vague about it).

One thing that helps is making sure your front tires are inflated to the MAXIMUM rated pressure listed in your owners manual. The more they squat the harder it is for them to turn sideways.
The steering is difficult to turn at any engine RPM when I have a load on the bucket. It was not that way when I bought it ~5 years ago. When I turn it feels like a pump with cavitation but there is no noise that indicates that. The front tires are fully inflated. No hydraulic leaks anywhere. The tractor is always kept in my garage. It has been serviced as recommended by Kubota. It has been getting worse over the period of this year but I did notice it last year when I went to move my horse trailer using the loader.
There are several components that could fail and given the price of all of them I do not want to replace parts that don’t need it. Please let me know if additional details are needed. I’m ignorant on the system and may not understand what should be discussed. Thanks!
 

Dave_eng

Well-known member
Lifetime Member

Equipment
M7040, Nuffield 465
Oct 6, 2012
5,239
1,022
113
Williamstown Ontario Canada
The power steering uses hydraulic flow from the main system and does not have its own pump.

There is no mechanical connection between the steering wheel and the front wheels.

The steering wheel moves a valve inside a controller at the base of the steering column. The controller routes flow to a cylinder between the two front wheels.

In the event of an engine failure while moving (run out of fuel for example) a part of the steering controller is a manual pump so steering is maintained but with greater effort

Lift the front wheels off the ground with the loader. Turn off the engine and see if you can turn the front wheels using the steering wheel.

If this test works, then the controller is not likely the problem.

The next likely culprit is the steering cylinder between the two front wheels.

There is a piston in the middle of the cylinder. Leakage by this piston reduces the effectiveness of the power steering.

Changing these two seals is the cheapest fix that has a high degree of success.

50117-c23a2b7adca6e037baab232570693f91.jpg


50118-a8c646064cac8792cd1be66c83b8d02b.jpg



Dave
 
Last edited by a moderator:

KD47

New member

Equipment
M5140
Nov 1, 2020
3
0
1
Alabama
The power steering uses hydraulic flow from the main system and does not have its own pump.

There is no mechanical connection between the steering wheel and the front wheels.

The steering wheel moves a valve inside a controller at the base of the steering column. The controller routes flow to a cylinder between the two front wheels.

In the event of an engine failure while moving (run out of fuel for example) a part of the steering controller is a manual pump so steering is maintained but with greater effort

Lift the front wheels off the ground with the loader. Turn off the engine and see if you can turn the front wheels using the steering wheel.

If this test works, then the controller is not likely the problem.

The next likely culprit is the steering cylinder between the two front wheels.

There is a piston in the middle of the cylinder. Leakage by this piston reduces the effectiveness of the power steering.

Changing these two seals is the cheapest fix that has a high degree of success.

View attachment 50117

View attachment 50118

Dave
Awesome information! I will try your test and follow up! Thank you!