B2910 Hydraulic Fluid Aerating

[fordman]

After running my B-2910 for a hour or so, if I drop it to an idle, I loose my power steering and my loader will barely lift the front end off the ground.The only time this happens is when Im using my Mid PTO for my belly mower.I can shut it down for 45mins. or so and when I start it back up its fine and everything works perfect.All this started when it had around 90 to 100 hours on it, and it has just continued to get worse.Ive had it to my dealer 8 or 9 times now and they have tried everything with no luck.They say they know the problem and its the hydraulic fluid aerating but they are waiting for Kubota to come up with a fix.It has been two months later and still no fix.I was wondering how many other B2410-2710 or B2910,s have had this problem and how they were fixed? I really need some help with this one and it looks like KUBOTA needs some also.

 

[Pks]

I have not had that problem with a B2400.

 

[fordman]

Thanks anyway...According to Kubota, only serial numbers 50001 thru 54546 were possibly having this problem,thats on the B2910 anyway....There may be others also,but Kubota is not even sure about that.

 

[ronjhall]

Fordman
There is a fix for your problem. I would call the<font color="orange"> Kubota </font>district office. Their phone number is on the back cover of your Owners manual. The customer service manger should be able to help you with the problem.

 

[fordman]

They are actually the ones who are telling me this ...
David Haggerty which is the district main service tech for the central division and Phil Bradshaw which is the National Tech Advisor in Torrance, CA. and he's telling me that they are woking with the Japan engineers to try to come up with a solution on all these tractors.

 

[Pks]

If <font color="blue">"...only serial numbers 50001 thru 54546 were" </font> having this problem, any idea as to why and any idea as to what was done to the other serial numbered units that don't have this problem?

 

[Bird]

Peter, I'm not sure of the serial numbers, but I do know that the early B2710's had a single spin on hydraulic oil filter (as mine did), but the later model B2710's had two separate spin on filters. However, I thought (not sure) that all the B2910's had the two filters.

 

[deminin]

I will be interested in hearing how this comes out. My 2910 falls right in the middle of the serial number range you quoted, but as yet, I have had no problems with my tractor. I do not use the mid PTO, just the rear. I have about 110 hours on my unit, and have done some serious work with it. A couple of weeks ago, I moved heavy stumps for about 4 hours with the loader, then graded the area with the rear blade, and landscape rake. At no time did the tractor hiccup. I do all the maintainance myself, and am using super UDT. Is it possible that you are using something other than super UDT, and it is breaking down under heat? Just a thought.

 

[ronjhall]

Fordman
The last I heard they had to changed items in the rear end of tractor.
Is your tractor out of the serial number range that you listed?

 

[fordman]

Yes my tractor is in that range of serial numbers.It's # 53737 ..Kubota had relocated a return line.Also they have a Production Servise Bulletin PSB-2002-045 that that includes the return line change,which my B-2910 has had done and still did not fix the problem.Kubota says this fixed some of them, but there is still a few that it did not fix.They also tried a bronze bushing as a restrictor that they put in the pumps discharge side to hold a little more volume,hoping that might help.and again that helped a few others but not mine.

 

[Rover]

Are there any more updates on this thread? My 2910 is starting to show this problem after mowing with my MMM. Its a very early 2910 (#50384) and is approaching 200 hrs.

This would seem to be from the hydro fluid getting too hot, since its doesn't have a problem until things get hot.

Rover

 

[fordman]

Rover
That sounds just exactly like the same thing mine was doing.Finally after 6 months we got it fixed.The first thing wrong as far as the steering goes,is the power steering relief pressures where set around 450psi to low.They should be set at 1636 to 1778psi with the engine totally hot at 2600 rpm.After raising my pressures up it made my steering turn really easy,as it felt like the front tires are off the ground.After using my MMM for 2 or 3 hours and then droping to an idle,the steering is not quite as free, but as soon as you give it any throttle at all it is back to normal.Kubota say this is normal because you loose approx. 10 to 15% of your psi and flow after the fluid is really hot.As far as my FEL goes it was almost the same story,it was set about 200psi to low also.It is set at 2000psi and Kubota says it wont hurt a thing to set it a little high,so we set it at 2150psi and that is at full throttle.And that is on a LA402,but if you look at the LA302 it has 1 1/2"
cylinders instead of the 1 3/4" on the LA402 but the LA302 sets at 2200psi.After raising my pressure up my loader works better than it ever did.

 

[chim]

The steering on my B7500 would get "lumpy" and difficult to turn after running ay PTO speed with the RFM for an hour or so. It seemed temperature-related. I took IF readings on the fluid cooling coils for reference (forget what the were, but i I posted them at one time). To see what would happen with cooler fluid, when it began to misbehave, I kept it running and sprayed water on the coils to drop the temp. It "fixed" the problem immediately.

The tractor was delivered with UDT. I changed the fluid at the 50 hour interval using UDT again, per my dealer's recommendation. The problem continued. I did tell my dealer about it so it wouldn't be a warranty issue later.

At 250 hours, I changed to Super UDT and the problem has yet to return.

Keep the screens and radiator fins clean as well. Don't know about your tractor, but my B7500 has the battery planted right in front of the coils and radiator - right where you'd think the engineers would want uninterruppted airflow.................chim

 

[Rover]

Thanks for the tip Chim,
My screens are clean and I'm running Super UDT after my 50 hr. service. I was thinking about using some AMSOIL to see if that would help and/or adding an extra cooler, but that for a different thread.

Just comparing this to my B8200 I traded in for the B2910, it had 11 less horsepower, no power steering and 3.5 liters more hydro in its case.

IMHO Kubota needs a bigger tank for the hydro oil and/or a better cooler for the B2910.

Rover

 

[Rover]

Update,

I talked to my dealer today, he hasn't see any tractors in his shop for this problem and was unaware of PSB. Thanks for posting the number here. He looked the PSB number up and looks I'll get this put in about 3 weeks, I'll also have him check the pressure at that time also. I figure this is not a big problem in this area as it is in hotter parts of the country.

BTW this is covered under 4.5 hrs of warrenty work for the dealer and looks like a fairly detailed tear down of the tractor just to get to the lines.

Rover