4720 Power Steering Intermittently Locks Up

[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)?