Kubota MX4700- Steering Locks Up when Loader Used

[EuropeanAM]

Let's see if anyone here has any ideas....

2009 Kubota MX4700 with less than 35 hours. Loader equipped 2WD model.

When NEW, steering worked flawlessly. Carried 800# on loader while steering with one finger.

At around 15 hours, the steering began to LOCK one way or the other anytime a load was on the bucket or forks. Doesn't seem to matter how much weight.... even 350# causes the steering to lock. Added RPM's make NO difference. Neither does dropping the loader back to the ground.

Problem seems more pronounced in warmer weather (80+ degrees). Once the steering locks, you have to set the load down, back up (steering still locked), and shut the tractor down for several minutes. Restart... 90% of the time normal steering function returns.

Been round and round with local dealer, Kubota Technical and Field Rep. Filters replaced, pressures checked, counterweights added, tire pressures checked, etc. etc.

Last communication with them was told "2 wheel drive tractor with loader won't steer with load on loader... you should have 4 wheel drive model". Offered to upgrade to 4 wheel drive for "X amount of dollars".

Still going on after 6 months.... called the field rep last week and said we'd agree to the upgrade (don't really NEED 4WD, but if it solves the problem... that is what we need to do). Told me the dealer would call us..... but no call after one week.

Really beginning to get aggravated.... love the tractor, but it kindof defeats the purpose of having a loader and forks IF YOU CAN'T STEER!!!

Suggestions???? Would really like to get this taken care of, or fixed. Stinks that we have to spend thousands of dollars to "fix" it, but if that's what's necessary.....

 

[jinman]

I would ask the dealer/rep one question. Why would they sell a configuration that will not work? If you added the loader after buying the tractor, then they might have a tiny bit of justification for their premise, but if they sold you a tractor with a loader, my demand would be that they make it work correctly or take the tractor back. Besides, I'd bet if you asked them to give you the details of why power steering would work better with 4wd, they'd be "blowin' smoke" your way.

My tractor is 4wd and may stall the power steering while it is sitting still, but as soon as I roll a couple of inches, it begins to work fine. The fact that you have to shut your tractor down and restart tells me that there is a cavitation, airlock, or some other malfuntion that has to bleed off before the power steering pump and control motor will work. Why oh why would you buy another tractor from somebody who couldn't make the first tractor work as it did when new? I think you're being fed a ration of BS and you know it. Don't let them off the hook. Be respectful, but be firm.

 

[Treemonkey1000]

I would agree the dealer is blowing smoke. Espcially since the tractor worked fine at first. Cavitation like the other guy said. Or you may have bent part of the frame or steering linkage. Up grading to 4wd is going to give you more power in the mud or snow is the only benefit. Still for them to sell you that rig and not be able to drive around with a load in the bucket is nonsense.

 

[art]

I'd try changing dealers! It is under warrantee.

 

[Gator6x4]

If memory serves several New Holland owners have posted with having the same problem when using a loader on a 2wd unit. You may do a search and see what their resolution was.

 

[mrmikey]

Not familiar with a Kubota system so I may be way out in left field here.
If it uses the same pump for the loader and power steering there may be a splitter valve in the circuit (if they don't use a power beyond configuration). If so, it sounds like the spool in the valve is hanging up, expanding due to heat. That would explain why shutting it down for awhile allows it to work, it allows the spring to center the spool once things cool off.
Just for the heck of it, trace out the plumbing from the pump and see if there's a splitter there, if there is the next time it screws up give it a sharp rap with a hammer......Mike

 

[nikdfish]

Back when we were shopping around for a tractor, we were talking with a Massey Ferguson dealer who described exactly the same thing happening with some of their smaller models. He had had customers that could not turn the steering wheel while standing still with a full load in the bucket.

He said the problem they had run into was the factory arbitrarily setting too low a pressure on the power steering pump, well below the pump's capacity. The fix they finally got the factory engineers to sign off on was increasing the size of an output aperture on a plate on the pump, which raised the pressure of the steering hydraulics to be comparable with that of models which didn't have the problem ...


Nick

 

[woodlandfarms]

So, I don't have this in question, but I can tell you a weirdness with mine that might relate.

PT's do the same thing, Can't turn when tilting or dumping (well, you can but tilt dump slow down a bit and sometimes stop).

it is related to the following on our machines. The pump that drives steering drives lift and tilt. It has a charge valve that keep the pressure up on the system.

My thought is that your charge valve (if you have one, it is this little gas cylinder looking thingy) might be empty. Sometimes they discharge.

Carl

 

[jinman]

The MX4700 has a dedicated 4.9 gpm power steering pump and a separate 9.5 gpm main hydraulic pump. If 4.9 gpm can't steer that tractor with 800 lb in the FEL, it's a sad, sad hydraulic day.

 

[Treemonkey1000]

The MX4700 has a dedicated 4.9 gpm power steering pump and a separate 9.5 gpm main hydraulic pump. If 4.9 gpm can't steer that tractor with 800 lb in the FEL, it's a sad, sad hydraulic day.

I agree with you Jinman. Maybe as someone suggested there is a valve that is sticking or crudded up. I would be an unhappy camper if that were my tractor having to shut it down to get the steering back..