4720 Power Steering Intermittently Locks Up

[bam747]

The power steering on my 4720 has a very, and I do mean very, intermittent problem where it will essentially lock up.

By "lock up", I mean everything had been working fine and then suddenly the steering wheel will freeze up. It has done this with the wheels straight ahead or strongly turned. It has done it in cold weather, warm weather, shortly after starting the tractor, and after hours or days of continuous use with nary a hint of a power steering issue.

When my tractor does exhibit this problem, it has always cleared itself up after cranking on the steering wheel for a minute, and then I never see the problem again that day.

I cannot reiterate just how intermittent this problem is, which is actually more frustrating that if the steering would have just permanently locked up.

I currently have the tractor at a local JD dealer's service department. They've had the tractor for two weeks, but of course they cannot replicate the problem. To the service managers credit, he did do a search in JD's service advisory system and DID find some reports of power steering problems with some possible diagnostic tests to run. Still, they have no idea what to fix at this time.

Has anyone else out there experienced this problem with their 4000 Twenty series tractor? If so, have you found a solution?

 

[Furu]

I also have a 4720. I have never seen anything like what you describe.
What year build do you have? Early or more recent? Is there any type of work that you are doing that might be related or has it happened in varied types of activity?

 

[bam747]

I also have a 4720. I have never seen anything like what you describe.
What year build do you have? Early or more recent? Is there any type of work that you are doing that might be related or has it happened in varied types of activity?

It's a 2007. Open station. It only has about 300 hours on it. 'Course, that means it is long out of warranty.

In retrospect, this problems seems to occur when doing lots of lock to lock steering wheel maneuvering while using the FEL. Note however that the bucket is generally empty and I'm not calling for any other hydraulic functions at the same time (i.e. not raising/lowering/dumping/curling the FEL or raising/lowering the 3PH rear blade nor performing any hydraulic angling/offsetting/tilting of the blade). 4WD is generally engaged when this happens. I generally see the problem in colder weather plowing snow, but just recently saw it in normal spring temperatures as well.

 

[jd110]

What size front tires are you running? Does it seem to happen if in soft ground? I had a customer some years back that was running extra wide tires on his 870 with duals on the rear. It would act the same way. We replaced steering valve, cylinder and raised relief valve in attempts to make it perform better, but the tires were just too much friction on the ground in certain operating conditions.

 

[bam747]

What size front tires are you running? Does it seem to happen if in soft ground? I had a customer some years back that was running extra wide tires on his 870 with duals on the rear. It would act the same way. We replaced steering valve, cylinder and raised relief valve in attempts to make it perform better, but the tires were just too much friction on the ground in certain operating conditions.

Standard factory R4 tires front (10.00-16.5) and rear (17.5L-24).
Hard ground and asphalt (generally with snow and ice on it, so "slickery").

Neither myself or the JD dealer want to just start replacing parts and hoping we find the problem, especially since 95+ percent of the time there is no issue.

Like I said, this is one of those very frustrating, and the very definition of an intermittent, and generally non reproducible problems, at least given my ultra low hour and infrequent usage of my tractor.

 

[Rockgod]

The only problem I ever had with my 4320 was a steering problem. Only I had the opposite issue, loose steering. When ever I'd go down the road in A range the problem would show up. The tractor would actually drift into the other lane. Turns out the steering cylinder/ram had an internal leak. They replaced it and everything was fine.

 

[sunnyside360]

I have a 2010 4320 open station which I bought new in February 2010. I experienced the exact same issue you described. It only occurred with mine with a very heavy load in the bucket of FEL. Someone here on TBN (kennyd iirc) said rear weight ballast was needed to in effect get less weight on the front wheels and allow the power steering to work (power steering relief valve tripping?). So I got a ballast box to use with the FEL and I haven't experienced the problem since. That was about 2 years ago.

Are you using the FEL when this happens? If yes, I suspect this is the same issue I had.

 

[bam747]

I have a 2010 4320 open station which I bought new in February 2010. I experienced the exact same issue you described. It only occurred with mine with a very heavy load in the bucket of FEL. Someone here on TBN (kennyd iirc) said rear weight ballast was needed to in effect get less weight on the front wheels and allow the power steering to work (power steering relief valve tripping?). So I got a ballast box to use with the FEL and I haven't experienced the problem since. That was about 2 years ago.

Are you using the FEL when this happens? If yes, I suspect this is the same issue I had.

Hummm...

Unfortunately, my lockup is occurring with and empty bucket. I cannot recall it ever happening to me with a heavy load on the FEL.

As for ballast, I have my Land Pride RBT3596 on the 3PH of the tractor at all times. It weighs around 1,000 lbs, and the blade hangs a good 4' out past the end of the lift arms on the 3PH. This provides a lot of counter balance on/around the rear axle. I also have two 110 lb JD cast iron weights on each rear wheel, or another 440 lbs of ballast centered on the rear axle. I also carry another 350+ lbs of, um, "ballast" over the rear axle when I'm sitting in the seat (yes, I'm the very definition of "big and tall" also being 6' 6" ).

My rig is pretty well ballasted for the FEL, excluding loading the rear tires. In my use so far, my blasting is working very well, even when I have a full load of heavy sand in the bucket. I've never come close to lifting a rear wheel off the ground, even when maxing out the FEL lift when digging a full bucket of dirt/sand out of a pile.

I do appreciate the lead on the "power steering relief valve" though. I will mention it to my service rep at the dealer.

Thanks!

Just for grins, here is a photo of me and my 4720 loading full buckets of sand into a full size tandem axle dump truck during a recent project to replace all the sand in an indoor arena. And no, the rig never exhibited the power steering lock up issue at all during the entire multi-day project.

 

[sunnyside360]

The cause of your steering lockup is completely different from mine but yours is likely in the power steering circuit. Those very intermittent problems are usually difficult to diagnose. Good luck.

 

[charleyfarmall]

Check your trans/ hydraulic fluid level. I don't think it is actually locking up. It's the pump momentarily not delivering pressurized fluid to the steering either from sucking a little air through it or for some other reason. The steering gets impossibly stiff when that happens.

 

[bam747]

So...

After three weeks elapsed time and 3+ hours of diagnostic time, the dealer was unable to reproduce the steering lockup problem. All their tests showed completely nominal functioning of all power steering components. Unfortunately, I pretty much expected this outcome.

To the dealer's credit, they do have and open "case" with JD corporate about the problem. Hopefully they will be able to use my info and report of the steering lockup problem to recognize any trends and possible repair solutions other than just performing wholesale (and EXPENSIVE) replacement of steering components.

In the mean time, it occurred to me that the next time this steering lockup occurs (as stated, once every other blue moon!), I need to lift the front end off the ground with the FEL to see if the steering breaks free easier/quicker with no load on the front axle.

Time will tell.

 

[Furu]

With the three way hydraulic adjust on the blade I presume you are getting that from the third SCV and the 4th and 5th diverter SCV John Deere option.
Did you install it yourself or did the dealer?
Did the steering problem ever happen before the addition of the 3-5 SCV package?
You state the blade is almost always on. Has it ever occurred with the blade off and thus the hydraulics disconnected? Should not be a factor but as is said when you rule out the obvious start looking at the things that should have no effect.
As I type I don't remember if you said if it has happened with and without the front axle drive engaged in 4wd or if you operate only with it engaged.

 

[bam747]

With the three way hydraulic adjust on the blade I presume you are getting that from the third SCV and the 4th and 5th diverter SCV John Deere option.
Did you install it yourself or did the dealer?
Did the steering problem ever happen before the addition of the 3-5 SCV package?
You state the blade is almost always on. Has it ever occurred with the blade off and thus the hydraulics disconnected? Should not be a factor but as is said when you rule out the obvious start looking at the things that should have no effect.
As I type I don't remember if you said if it has happened with and without the front axle drive engaged in 4wd or if you operate only with it engaged.

Rear Hydraulics:

I ordered my tractor exactly the way I wanted it, including the "3rd" and "4th" and "5th" diverter SCV options. I assume they were installed at the factory, but they may have been dealer installed when they received the tractor. In any case, I did not install them myself.

Rear Blade Use:

The rear blade is the largest part of my FEL ballasting, so I've never run the tractor without the rear blade attached by default, unless I was (rarely) using some other 3PH implement like a rotary mower.

4WD Use:

I typically have the 4WD engaged whenever I'm using my tractor. I really only disengage 4WD if I need to make a bunch of tight maneuvers or am running a significant travel distance without using the FEL or a 3PH implement. I guess I'd have to say that I'm experiencing this problem mostly with the 4WD engaged.

I do appreciate all the feedback I've been getting on this issue. The next time it happens I'll have a few more new things to try to see if they help break the steering loose quickly. I also hope to have the presence of mind to try to video the problem with my smart phone, but I don't know what good that can really do other than "prove" that I do have the steering lockup problem.

I also wanted to point out for readers of this thread that even with this inconvenient, but non "fatal" steering lockup problem, I really do like my tractor a LOT!

 

[Red Horse]

2007 4720 here with a bit over 500 hours. ballasted R-4's, and either 600lb concrete block or heavy rear impliment-96" LandPride power rake, MX-5 etc. Never a problem. How does your fluid look? clear and bright? Kind of disappointing that a dealer with their access to factory tech support can't diagnose this? we are not talking about a $20,000 "made on the banks of the Yangtze" tractor!

 

[jenkinsph]

bam747,

Might wan't to call the dealer and have him send over the mechanic when it happens next time, much better if they can see the problem first hand. I would also suspect that Deere corporate would want to fix this problem at a low or no cost to you to eliminate future liability issues.

 

[rdscutter]

I have a JD 4720 with the same steering lockups. My dealer has replaced the following parts on my 2011 4720 : Hdrly pump & steering piston & the steering valve system. Did not help. Next is the front axle going take it apart to see if there is bad bearing inside. I had a 2008 and also a 2005 4720 no! trouble with them.My dealer has also someone with 4320 same trouble.

 

[bam747]

I have a JD 4720 with the same steering lockups. My dealer has replaced the following parts on my 2011 4720 : Hdrly pump & steering piston & the steering valve system. Did not help. Next is the front axle going take it apart to see if there is bad bearing inside. I had a 2008 and also a 2005 4720 no! trouble with them.My dealer has also someone with 4320 same trouble.

Thanks for the info. Unfortunately for me with only 350 total hours on 2007 my tractor, it is no longer covered by by the ridiculous 2 year or 2000 hour factory warranty. Therefore I am NOT going to pay a dealer thousands and thousands of dollars to just try replacing any and everything associated with the steering in the vain hope of actually fixing the problem they can't reproduce in the first place.

BTW... Just today I had to plow snow, and guess what? The steering did it's random lock up thing! And yes, it was cold, but the steering didn't lock up until after a few minutes of use. But, I tried the "trick" I had thought of over the summer to break the steering loose, and it did the job.

And the trick? Lift the front tires off the ground with the FEL and crank the steering wheel from lock to lock. Bingo! The steering was back to normal and behaved normally for the rest of the hour spent plowing snow. Go figure!

 

[rdscutter]

I have a 2011 4720 same trouble. My dealer has replaced the following parts. Steerig pump/ steering column/ steering pistom/and also taken apart the front axle and found nothing worng with it .Trouble started after it was 1 year old. My 4720 dose the same as yours but gets locked up more often.

 

[rdscutter]

Have your Dealer call the John Deere Rep in your area and have him get in touch with you .Dealers will not give you the number with 350 on hours your 4720 is nothing, I do about 450 to 500 per year. This is my 3 - 4720 my 05 & 08 ran great no trouble. Talk to a Rep

 

[bam747]

I have a 2011 4720 same trouble. My dealer has replaced the following parts. Steerig pump/ steering column/ steering pistom/and also taken apart the front axle and found nothing worng with it .Trouble started after it was 1 year old. My 4720 dose the same as yours but gets locked up more often.

Was your dealer's service department able to reproduce the lockup problem or did they just replace, apparently, everything related to the steering on your tractor (under warranty I hope)?