Power steering loosing power

[JClark]

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]

<font color="blue">these tires are very nearly the same size as the stock R4s</font>
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]

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]

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]

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]

<font color="blue"> Maybe I just need to go to a more cooperative dealer. </font>
I think so.
Have you looked at JD's online parts?

 

[JClark]

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]

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]

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.

/forums/images/graemlins/smile.gif<font color="blue">D</font><font color="orange">E</font> <font color="green">L</font>/forums/images/graemlins/smile.gif

 

[JClark]

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.