B2710 Steering problems

[Ian]

My tractor has been gone for a week now /w3tcompact/icons/crazy.gif... No problem getting the dealer to work on it (I'm never an optomist when it comes to warranty work). In fact, the service manager seemed familiar with the problem. I'll ask him if Mr. Kubota has a service bulletin out on it.
What I did notice before sending the tractor out was that the hydraulic lines going to the hydraulic pump make a couple of 90 degree bends shortly before the pump housing - that can't be too good for smooth oil flow at high volumes.
I'll post the results - good or bad - when I get my tractor back.

 

[Ian]

Yes! There is a fix.
Good news...the service manager says that they will install a new hydraulic filter and line...redesigned to reduce what is probable cavitation at the pump.
Bad news...they're waiting for parts /w3tcompact/icons/frown.gif .
I will check the part number of the hydraulic filter when I get the tractor back to see if it's different.

 

[Bird]

Thanks for the information, Ian. Does Kubota have a service bulletin on this little problem, or is this just something your dealer came up with?

Bird

 

[Ian]

Bird - I'm not sure if it's a "homebrew" fix or not. If it's a slow day at the plant tomorrow, I'll call the distributor's service department and ask. Failing that, it will be Friday (best case) before I get the tractor back, and can take a closer look at what they've done.

 

[Alan L.]

I'd like to know if Kubota is officially changing something. If so, I want to get it done. I had the problem last summer but maybe only briefly this summer. They had suspected cavitation in hot weather at the time.

 

[ChrisfromCT]

Maybe a stupid question....
Could these problems be caused by a small amount of air in the hydrolic system? Therefore some have it and some don't? I know hydrolic pumps make noise when they get air in them, but maybe a small amount of air wouldn't.

Also, would an air pocket change size, expand / contract based on the temp on the fluid?

I'll keep a lookout for this on my machine.

Regards,

 

[Anonymous Poster]

I have also wondered about air but have not had other symptoms of that. I am bringing mine to the dealer tonight. When I talked to them Monday they did not know of a simple fix when we discussed it since I had tried to purge air, clean radiator etc. I used it last night to tow a little trailer around the property picking up branches and it was doing it some of the time. I could also hear the pump groan at low idle at times when turning the wheel. Normal? or air? I will post what happens when I get it back but I do not have that much faith. I would like to know more about the fix that was mentioned.

 

[Anonymous Poster]

For what it's worth, the design of the steering hydraulics changed between the B1700,2100,2400 series and the 2710,2910 series. The older models have a single hydraulic pump and a diverter valve that forces some portion of oil flow through the power steering mechanism to ensure it never gets starved. Under certain conditions, like full bucket on pavement, the power steering could not keep up. I've experienced this first hand on my B2400.

Presumably to address this issue, the B2710 and 2910 (not sure about the 2410) have two pumps, one dedicated to the steering, and the other for the loader etc. Sounds like there's a first-year-design-bug that needs to be fixed in this new approach.

 

[bsauter]

I brought my B2910 in last night armed with info from this site to try and help them along. The lead mechanic immediately put a call in to the district service rep to try and find out more about this problem. Our rep services 107 dealers here in the midwest so I don't know if they will hear back from him today or not. The mechanic and the owner of the dealership were talking to me in the shop about it and the owner said "Sounds like cavitation in the pump" so I took out my printouts from this thread and said that had been mentioned too. We will see what Mr. Kubota comes back with and what the dealer can do. I hope really though that all they have to do is change fluid or purge air or something since the tractor is only 2 1/2 weeks old.

I know what cavitation is in diesel engines but exactly what is cavitation in the steering pump?

 

[Bird]

I called my service manager yesterday and told him what the power steering does sometimes and he immediately said, "Sounds like air in the system." But he hadn't run into the problem before and didn't know of any service bulletins. He said he'd do some checking to see if there were any service bulletins.

Bird