B2150 power steering box problems

Brettmcc1 · Jul 27, 2017

I've just bought an old B2150 with HST, with a blown out bottom seal behind the pitman arm, I have replaced the seal with a new one but as soon as I operated it, it blew it straight out again. Any help would be appreciated.

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Dave_eng · Jul 27, 2017

Can you plse identify the number on the following parts illustration where you are having a seal blow out.

If I am looking at the correct one, does the pitman arm itself not hold the seal in?

Is the seal physically coming out or leaking.

If it is just leaking, could you have it in backwards?

Dave M7040

Brettmcc1 · Jul 27, 2017

Seal 050 and yes the seal is physically coming out as there is about a 15 to 20mm gap between the seal and the pitman arm. Seal has been fitted with part numbers (flat side) facing out.

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Brettmcc1 · Jul 28, 2017

Brettmcc1 said:
Seal 050 and yes the seal is physically coming out as there is about a 15 to 20mm gap between the seal and the pitman arm. Seal has been fitted with part numbers (flat side) facing out.

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This is what it looks like

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Dave_eng · Jul 28, 2017

I wish I knew the type of power steering on your unit.

After looking that the pictures, I am wondering if there is hydraulic pressure in an area where there should not be any and this is what is forcing out your seal. The style of seal on your box is not one intended to hold back 1,500 psi of hydraulic pressure.

Can you post pictures of where the power steering hoses attach either to the steering box or the steering linkages.

I assume the pressure for your power steering is coming from the main hydraulic system within your tractor and there is not a separate pump and reservoir for the steering.

Sometimes the steering is hydrostatic which means there is not physical connection between the box and the front wheels but with the steering arm on your box that is not the case in my mind.

On my M7040, the steering wheel is connected to a hydraulic valve. As you turn the wheel, hydraulic pressure is fed to a hydraulic cylinder which is part of the steering linkage at the front axle.

On cars from the 1970's, the hydraulic power was applied to internal parts within the steering box to add to the effort you applied by turning the steering wheel.

If your box is that type of power steering, an internal seal leak in a high pressure area could be resulting in the problem you are having.

Your case may be such that talking to a Kubota dealer about rebuilding your steering box may be the most practical solution. You may save money by removing the box, you may not.

Getting the WSM for your tractor would be the first step as internal adjustments during the rebuild will be important.

Dave M7040

100 td · Jul 28, 2017

X2 with Dave on HP oil where it shouldn't be, leaking from valve area into the rack/shaft area.
I thought I had a B2150 WSM but have deleted a lot of stuff I didn't need recently, if I am correct and it was a B2150, think I bought it from tradebit for $10, can't remember for sure. Some other kubota tractors have the same steering system so a WSM from something else may get you out of trouble in conjunction with the illustrated parts manual online.

Dave_eng · Jul 28, 2017

The recirculating ball portion of the steering box will be acting as the piston in a hydraulic cylinder. the valve assembly on the upper part of the steering box will be feeding oil to the top or bottom of the part.

Dave M7040

100 td · Jul 28, 2017

Hey Dave,
I've only seen one of these stripped on the bench, never had a look at the oil flow, does HP oil get on the bottom side of the piston/nut shaft area?

Dave_eng · Jul 28, 2017

High pressure oil has to get to both ends of what is in effect the piston to have power steering when turning either right or left.

All it takes is a small passage from the valve assembly to the lower side of the piston.

Dave M7040

100 td · Jul 28, 2017

So is 40 a HP seal on the shaft?

Dave_eng · Jul 29, 2017

100 td said:
So is 40 a HP seal on the shaft?

40 is a gasket.

http://www.messicks.com/ku/84458

Dave M7040

Brettmcc1 · Jul 29, 2017

Dave_eng said:
I wish I knew the type of power steering on your unit.

After looking that the pictures, I am wondering if there is hydraulic pressure in an area where there should not be any and this is what is forcing out your seal. The style of seal on your box is not one intended to hold back 1,500 psi of hydraulic pressure.

Can you post pictures of where the power steering hoses attach either to the steering box or the steering linkages.

I assume the pressure for your power steering is coming from the main hydraulic system within your tractor and there is not a separate pump and reservoir for the steering.

Sometimes the steering is hydrostatic which means there is not physical connection between the box and the front wheels but with the steering arm on your box that is not the case in my mind.

On my M7040, the steering wheel is connected to a hydraulic valve. As you turn the wheel, hydraulic pressure is fed to a hydraulic cylinder which is part of the steering linkage at the front axle.

On cars from the 1970's, the hydraulic power was applied to internal parts within the steering box to add to the effort you applied by turning the steering wheel.

If your box is that type of power steering, an internal seal leak in a high pressure area could be resulting in the problem you are having.

Your case may be such that talking to a Kubota dealer about rebuilding your steering box may be the most practical solution. You may save money by removing the box, you may not.

Getting the WSM for your tractor would be the first step as internal adjustments during the rebuild will be important.

Dave M7040

Some pics of the hyd valve that supply the steering box, I can not see where the lines attach to the steering box without a fair amount of disassembling.

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Brettmcc1 · Jul 29, 2017

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Dave_eng · Jul 29, 2017

Thanks for the photos and illustrations.

My opinion remains an internal seal has gone and hydraulic pressure is getting into an area of the steering box where it is forcing the seal out of position.

The hydraulic valve is likely a priority flow control making certain you always have sufficient flow for the power steering as steering is far more safety oriented than how fast the FEL works for example.

Do you know the history of your machine and if someone without the proper knowledge was into the box before you got it?
Dave M7040

Brettmcc1 · Jul 29, 2017

I don't believe that the box has been apart before as there was no paint disturbed before I removed the nut from the sector shaft, but I do have very little knowledge of the history of this machine. I know part 040 said it's a gasket but is there a chance it should be a pressure seal ?

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Dave_eng · Jul 29, 2017

Plse look at the web site Kubotabooks.com and tell me if the WSM for the
B1700, B2100, B2400 is the same as your B2150.

Part 2 of the WSM has an explanation of the steering system which I am just starting to read.

This is the link to part 2 of the WSM

http://kubotabooks.com/AutoIndex/in...s/&AutoIndex=ccf99936fe184678719ca6abcf20b427

Dave M7040

Dave_eng · Jul 29, 2017

In the WSM I sent you the link for, there are a number of what are described as "U" seals which fit into grooves in the steering box housing.

To see these seals the sector shaft would have to be removed to get to the one where you are having problems.

Being in a groove in the housing with the sector shaft going through the center of the U seal means the seal is not able to slide out.

What is the part number for the seal you bought?

If you were given the seal for a non power steering box and used it with power steering it would explain your problem

Dave M7040

100 td · Jul 29, 2017

Dave, from the manual you have listed, the following pic shows what appears to be a HP seal on the inside of the housing with a dust seal on the outer. If his is like this, then it's likely the inner seal which may be faulty. It's located next to the bearing, whether that corresponds to the "gasket No.40" is another question. I can't see any reason for a gasket to be in that location, unless it's a hp seal?

100 td · Jul 29, 2017

Dave, just had a look at the parts listing for a B2100 (your WSM link goes to this model), the "Gasket" next to the bearing is listed as a "Gasket-U", so item 40 in the original 2150 diagram is in fact a HP seal I suspect, and is likely to be shot, or under more pressure than it was designed for if relief is faulty, or the bearing/shaft is flogged and allowing HP oil to pass.

Dave_eng · Jul 29, 2017

100 td said:
Dave, from the manual you have listed, the following pic shows what appears to be a HP seal on the inside of the housing with a dust seal on the outer. If his is like this, then it's likely the inner seal which may be faulty. It's located next to the bearing, whether that corresponds to the "gasket No.40" is another question. I can't see any reason for a gasket to be in that location, unless it's a hp seal?

You are right and further the outer/dust seal goes in opposite to what the owner Brett is doing. It is intended to weep if the U seal starts to go and not try and hold back the high pressure.

Brett, pay particular attention to this illustration!!!!

Dave M7040

B2150 power steering box problems

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