Power steering loosing power

del · Feb 21, 2004

( I think one of the bigger
disappointments is the time it took to get pressure readings
on the pump. I think it would be reasonable to expect a more
responsive trouble-shooting process than JClark has seen. )

Am I missing something, or isn't it a bit bizarre the dealer
did not have a pressure guage or flow tester?

I was thinking of getting a pressure gauge for my home use.

Or is that a great sign that such things are NEVER NEEDED,
even my a dealer's shop?

Seems like one of the first things you'd have on hand after
a grease gun and oil drain pan...

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nailerguy · Feb 21, 2004

Big Pete, I think that many of us did not look closer at the caster issue because the problem did not occur when JClark changed the tires. At least thats why I did'nt.

To exaggerate your theory a bit,if you were to raise the back of the tractor to a 45 degree angle and try to turn the front wheels, it would be nearly impossible as the tires would literally have to move the tractor in order to turn from full left to right. The tire would in effect become a lever when the wheel was turned rather than rotating on it's axis.

Nailerguy

bigpete · Feb 21, 2004

Nailerguy, I think that many of us did not look closer at the caster issue because the problem did not occur when JClark changed the tires. At least thats why I did'nt.
 Me too.

I think JClark told us originally that he noticed difficulty steering under a heavy load right after the hydraulic change. It was only later on he mentioned that the RM told him that he needed to get stock tires on the tractor. So I guess none of us really knew/know when the bigger tires were installed, or even that there were bigger tires until the RM mentioned it. When I first started following this thread I was sure, in the back of my mind, that a chunk of the siphon screen or magnet had broken out and cosntricted flow, or something like that--something from the hydraulic change.

The cause of the steering difficulty is almost certainly a combination of things now that we know a little more. Most likely the low-end hydraulic pressure would never have been noticed with stock rear tires, And...most likely the larger rear tires would not have caused any problem if the hydraulic pressure were in the mid-to-high range of the spec. That's my theory, anyway. It's still only a theory..

As to the old-time farmers using bigger rear wheels...putting even bigger wheels than an engineer intended on an old tractor without power steering will continue to make it a PITA to turn under a full front-end load. Ever used an ag tractor without power steering and with a front-end loader? You can't turn the front wheels unless you are moving, no matter what size rears you have on. If you ever screwed up the steering dynamics on an old tractor, it would be hard to tell. With power steering, we've grown to expect fingertip steering under any condition. It's not like the conditions with JClark's tractor were completely disabling. /forums/images/graemlins/shocked.gif

JerryG · Feb 21, 2004

There is no use saying anything else until JClark revisits with an update. Theories are not worth anything unless they are proved or have experience to back them up.

Trev · Feb 21, 2004

The thing about this that has always puzzled me, and perhaps just because I don't know much about the mechanical aspects involved, is that he says the wheel turns one half turn in either direction, and then simlpy won't turn any further. Why one half turn? Is there a clue in that which we're missing?

Bob

bigpete · Feb 21, 2004

Theories are not worth anything? Sure they are, Jerry! Lighten up! /forums/images/graemlins/grin.gif It's a discussion forum. I thought that was why we are here. You've shared your theories here at TBN on occasion, and I think in this thread, haven't you. /forums/images/graemlins/confused.gif

As far as experience, I own a 4110. There's tons of related experience from other members weighing in on this thread. I have been operating farm equipment for over 30 years, and some light construction equipment along the way. Most folks who are offering conjecture here are doing so from experience, reference, or the science in the matter.

JClark has reported recently. It has helped us to further our theories and perhaps some of these theories have helped him work toward resolving his problem. I'm enjoying the discourse, too.

JerryG · Feb 21, 2004

Pete,
We'll find out what is going on if his dealer will ever check it out. It just blows my mind how someone that calls their self a dealer can't even check his pressure.

bigpete · Feb 21, 2004

I think there's a post back a page that mentioned that his dealer did finally check out the pressure. It was at the low end of the spec range. They are adding shims to boost the pressure. We just need the report on whether that helps to remedy the condition.

It's now been said several times that it is amazing that a certified JD dealer would not have a set of tools for measuring the operating pressure of a hydraulic system.

JerryG · Feb 21, 2004

I must have missed it some how. Don't think that I would want them for my dealer, but sadly there seems to be more and more dealer like that every year.

DennoAce · Feb 22, 2004

bigpete, I hear ya, and thanks for the links. I am aware of this condition and of course it matters but not to this extreme in this case. He didn't put tires that were 10 feet high on the rear. If the PS system is that close to being maxed out then JD has a piss-poor design..which I'm sure is not the case. /forums/images/graemlins/smile.gif

I remember why it was discussed at all...because the JD rep mentioned it. I guess what I meant was I don't understand why it is still being discussed. I guess I will just have to say it plain...there is no way in hell those larger tires should affect the front steering on this little tractor. There is a universe of difference between a car that goes around a smooth track/road and a tractor with a bucket on the front and the design capability to lift hundreds of pounds off the ground front and rear, on purpose. If this is true than the steering would be inadequate every time he went down a (reasonable) slope forward, especially with a bucket full. And I assume this tractor was designed to do that and still be able to steer. Yes I know there is a diff. between caster and shifting weight to the front (ala going down a hill or adding larger rear tires), but the impact on the steering pump in this case would be similar...all the system understands is "too much load for me so I give up". It has no clue what angle the pieces are sitting at.

Anyway... next. Isn't this fun? /forums/images/graemlins/smile.gif

JClark · Feb 22, 2004

Jumping in on the steering/bigger tires issue. As I said upthread, the oversize rear turf tires were installed at about 10 hours. The steering problem started at about 60 hours, right after the hydraulic oil change.

It would be tought to convince me the tires have anything to do with this particular steering problem. For one, these tires are very nearly the same size as the stock R4s. Also, my tests to demonstrate the problem or gauge what difference various changes make are always done with the tractor stationary. Another point: with the stock R3s, at recommended inflation levels, the tractor squats noticably while a 4110 with stock R4s does not. My larger rear turfs bring the tractor's attitude much closer to stock R1 and R4 setup.

The reason the steering craps out as the steering angle increases is because the effective lever on the front wheels decreases the farther the steering wheel is turned. At center the steering cylinder has the full length of the steering arms to turn the wheels. As the arms get at a greater angle to the steering cylinder axis the effective leverage is reduced. Shows how close to max the system is working, I think.

JerryG · Feb 22, 2004

these tires are very nearly the same size as the stock R4s
If that is right, then go to the manufactures site and check out the Static Load Radius and also the Rolling Circumference. That might give you the information that you need should they try to say that the size difference is the problem. Also look at the front to rear ratio information that Firestone Tire has on their site. These things might help you out if they push it. Good Luck

JClark · Feb 26, 2004

Today I brought my tractor home from the dealer and I am happy to say it works better now, although not as well as before this problem appeared.

The mechanic added some shims to the pressure relief valve to bring the steering hydraulic pressure up to the specified 1500#. He did not remember the beginning pressure or how many shims he added but said the shims are paper thin and each one raises the pressure by 200#.

Since I need to do the cleanup anyway I am going to pull out the valve and count and measure the shims. I fully expect this problem to reappear sometime later in this tractors life so I want to have some additional shims on hand. The dealer refused to sell me any additional shims so I will make a few.

I was told by a reliable source that JD was no help at all to the dealer in resolving this problem. After my meeting with the field rep I don't doubt it. The mechanic ended up making an adapter so they could attach the pressure gauge to the system. I have a picture of it and will post it if anyone is interested.

While I am relieved to have this behind me, my confidence in both John Deere and this dealer is now very low. I am going to cross my fingers and hope nothing else major goes wrong. Any minor stuff I will take care of myself and I think I can fix this problem myself should it come back.

Thanks again to everyone for their considerable help and support.

JerryG · Feb 26, 2004

JClark,
Glad the it turned out that way. /forums/images/graemlins/cool.gif As far as the shim, go to the parts dept. and have them order them for you.
By all means post the picture. /forums/images/graemlins/grin.gif

JClark · Feb 27, 2004

The parts department has no part number for the shims so would not order them. The parts diagram shows the shims but does not identify them by name or number. Maybe I just need to go to a more cooperative dealer.

JerryG · Feb 27, 2004

Maybe I just need to go to a more cooperative dealer. 
I think so.
Have you looked at JD's online parts?

JClark · Feb 27, 2004

Yep, and the online parts diagrams are exactly the same as the dealer has, except the online is updated sooner (so the parts guy tells me).

It would probably be worth my while to invest in a technical manual but I am almost afraid to ask how much one costs.

Old_Hickory · Feb 27, 2004

I bought 2 shop manuals on E-bay for not very much.
1 manual covers the 4200,4300,4400 the other covers the 4500,4600,4700. Very nice to have when working on the tractor,step by step instructions.

del · Feb 28, 2004

Does the valve you shimmed have any other stamping (name)
on it. JD doesn't make many of the hydraulic components.
For instance, Kubota uses Husco valve bodies on their backhoes.
I needed one of the valve sections, through Kubota it was about
$500. Through a Husco distributor it was $150 for the same part,
and that was RETAIL.

Came grey instead of black though/forums/images/graemlins/frown.gif .

Maybe the manufacturer of the part can get the shims. I'm sure
JD doesn't want everyone shimming things and busting up things.
You can literally tear a loader or backhoe (or steering linkage)
apart by going crazy with the pressure.

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JClark · Feb 29, 2004

The valve is integrated into a section of the transaxle so I don't expect there is anywhere else to go for parts.

Since my tractor is now fixed after only three short months I started a new thread to address the pressure control valve issue, complete with pictures.