B1700HSD steering leak

[Tyler_LaRue]

I’ve developed a leak in the steering line that drips too fast to be usable. I thought it was the rear of the propeller shaft but upon closer inspection it is the O-ring in the steering hydraulic line where it mounts into the bottom of the pump near the rear of the tractor. I have tried every O-ring size imaginable that fits and it still leaks. The parts diagram shows two O-rings one on top of the other I’ve never seen this before Is this normal. I’ve tried 1, 2 and, 3 O-rings. Depending on the size of the O-ring the amount of leakage changes but never stops has anyone ever ran into this issue or have any advice. I have attached photos of the line in question.

thank you

 

[Dave_eng]

To rule out any misfit issues I would buy the two Kubota O rings and not be using generic ones.

Also, check the line carefully for any crack or distortion that will prevent the O rings from seating in the bore in the steering housing.

The sides of the bore in the housing where the O rings seat needs to be very clean and free of scratches and nicks.

Am I right in thinking this line is on the low pressure side of the steering box as it is getting oil that has been through the oil cooler?

My point is the above question is to suggest this is not a high pressure point in the hydraulic system so there should be a visible reason for a leak as it is not under high pressure.

Replace the entire line for $64 before taking it to a dealer to fix.

Dave

 

[Tyler_LaRue]

Thank you for your reply. All is clean and I can’t see or feel any nicks. Yes I believe it is low pressure and yes it comes from the cooler. I saw that the line and o rings were reasonably priced. Is it normal to put one o ring on top of the other? I’ve never see that before.

 

[Dave_eng]

When the Space Shuttle was still flying, its solid rocket motors used multiple O rings seals between sections.

Otherwise, it is rare in my experience.

Are there grooves for the O ring to seat in in the pipe?

Dave

 

[Tyler_LaRue]

When the Space Shuttle was still flying, its solid rocket motors used multiple O rings seals between sections.

Otherwise, it is rare in my experience.

Are there grooves for the O ring to seat in in the pipe?

Dave

No there is not a groove. I found that odd. Yeah I’m not sure why the parts diagram shows two orings.

 

[lugbolt]

the book shows 2 o-rings and indeed there is supposed to be TWO o-rings (stacked). Leaks are guaranteed with only one. Just went through it on a B2400 (same tractor more or less)

u can't just use any old o-ring either it has to be the right material and people forget this all the time. I don't know what the material is that kubota uses; but it's a little harder than anything u would buy at a parts store

dave_eng is spot on with his recommendation of using the kubota o-rings they are dirt cheap in comparison to the frustration that you've already gone through

 

[torch]

Otherwise, it is rare in my experience.

I have a couple of hydraulic floor jacks that each use double o-rings around the piston.

 

[Tyler_LaRue]

the book shows 2 o-rings and indeed there is supposed to be TWO o-rings (stacked). Leaks are guaranteed with only one. Just went through it on a B2400 (same tractor more or less)

u can't just use any old o-ring either it has to be the right material and people forget this all the time. I don't know what the material is that kubota uses; but it's a little harder than anything u would buy at a parts store

dave_eng is spot on with his recommendation of using the kubota o-rings they are dirt cheap in comparison to the frustration that you've already gone through

I agree and ordered the factory replacement today. However I did find a size to get me by until they arrive. Danco #31 9/16” O.D. X 5/16” I.D. X 1/8” thick seals it up. This is a very thick o ring and one was enough to seal it up. Found it at my local Lowe’s. No telling how long it will last but I surmise it will last until the new ones arrive and I was able to beat the rain and complete the project. Thanks for the help guys

 

[Dave_eng]

What many do not appreciate is that, although appearing the same or similar, O rings are made from a wide range of materials each with a different property.

This is a case where size is only one of the parameters to duplicate.


Materials include

• Nitrile (Buna-N)
• Ethylene Propylene Rubber (EPR)
• Fluorocarbon (Viton)
• Neoprene.
• Polyurethane.
• Silicone.
• PTFE.
• FFKM.

High performance O rings are expensive and you will not find them in hardware assortments.

I have a simple tool that tells you the O ring material. In simple terms it drops a steel ball from a fixed height unto the O ring. The height of the bounce tells you which material it is made from.

This short video is worth watching as you quickly see the big difference in O ring material properties

O ring material testing

Dave