Power steering loosing power

NIXON · Feb 11, 2004

I've been following this thread since it began . It seems like your dealer is trying to dodge the issue . You've got a lot of patience in my book . I keep coming back to this thread hoping to read that it's been fixed . JD has a good reputation and I'm sure it will be taken care of by them . Have you gone over the dealers head yet ? Good luck , John

higgy · Feb 11, 2004

I just went through this with my bota. I zeroed out a front tire this last week end when moving snow. I could not get a new tire of the same brand as stock and the bota dealer said that he could not get one with out a rim in it!? I went to the local tire supplier and we looked at what he had. The front tires are 10-16.5 and when we put them next to each other there was about a 1 inch difference when not inflated. I was worried about that much difference and the possible binding it could put on the transfer case, and I would need two new fronts as not to drive the diff all the time.

The rule of thumb that the tire people go by here is 5% allowance on 4x4 between front and back when looking at the damiter. That made the 1 inch in 30 3%.

One thing of interest in the 3130, the stock tires are only 6 ply from the dealer, man, that is a light tire.

We put the new 10 ply tire on the rim and inflated the tire and there is very little difference when mounted. Bought two and off we went.

The tires that I put on are anvil wall, 10 ply, stronger and less expensive the stocker ones.

I have been very happy with the new ones.

Any way I got off track. Measure the diameter of both the front and the back and do a calculation, is it with in 5% (rule of thumb here)?

If it is as them what the allowable difference is, or maybe the poster that is a JD tech could let us know what JD thinks as it would be a number supplied by a non biased reference.

If it is with in the 5% or the allowable difference that JD states then you have weakened their argument.

Did the dealer remember you talking to them before changing the rear tires?

Sorry that this is so long.

Dane

Trev · Feb 11, 2004

( Measure the diameter of both the front and the back and do a calculation, is it with in 5% (rule of thumb here)?)

Hi Dane,

Not sure I'm following you here.. and this is probably a dumb question.. but when you have BIG tires on the back, and little ones on the front, like most of the CUTs, how do you derive the 5% figure you mention? Is it from what the manufacturer states the diameters *should* be?

Tks,
Bob

higgy · Feb 11, 2004

That is the way it was explained to me. Each tire is made with in a range as not all tires are the same in dimension from the different manufactures. When the calcs are done for the ratio of front tire to back tire there is a 5%(rule of thumb, please check with your manufacturer) range that will not cause problems in the drive line.

I would think if this true and the tire even though not the same as new are with in the range there should not be a problem.

By doing a calculation the range of tire heights that should work can be gotten.

For example if the stock tire is 100 inches 5% would be 5 inches which would give a range of 97.5 to 102.5 as workable tire heights.

In my case after mounting and inflation to 40 psi there was only a 0.5% difference, even though when looking at the tires it seemed like a big difference.

I have put 10 hours on the new tires with no problem at all.

Trev · Feb 11, 2004

( In my case after mounting and inflation to 40 psi there was only a 0.5% difference, even though when looking at the tires it seemed like a big difference.)

Thanks, that makes sense. But, 40 PSI?? I run mine at around 12... /forums/images/graemlins/smile.gif

Best.............Bob

keeney · Feb 11, 2004

As far as steering losing power, I have noticed that my machine would occasionally lose power steering when trying to move the maxed-out loader and trying to back out of a low spot at the same time, or some similar combination. I think it was just at the limits of the power steering pump pressure.

Other times, on side hills, sometimes, it seems like the power steering pump is starved for fluid. I checked the level and it seemed fine. I plan to change the filters and fluid out soon - maybe that will help mine.

My understanding is that the JD OEM tire combinations are intentionally chosen to give a slightly higher ground speed on the fronts than the rears to help with steering traction and response.

- Rick

higgy · Feb 11, 2004

I change mine depending on the surface that I am working on. With the new tires I can go all the way to 60 if I want, Can’t say that I have many reasons for doing so but hey at least I have the option.

When operating of dry ground and using the loader I run higher pressure to keep the tire wall from distorting to badly, this can cause high torsion on the tire and I have had them fail when doing sharp turns with less air in the tire.

The worst was on my plane, as it was a taildragger, lock one wheel to turn and the torsion on the pivot wheel is very high.

What does this have to do with tractors< when using differential breaking you set up the same types of forces on the back tires.

Haven't done that in a lot of years, but I am careful not to do it anyway.

tc35dforme · Feb 11, 2004

My understanding is that the JD OEM tire combinations are intentionally chosen to give a slightly higher ground speed on the fronts than the rears to help with steering traction and response.


Now that's something I can't understand. If the front has a higher ground speed, won't the tractor eventually become very long. I would imagine the ground speed ( speed of the unit relative to the ground ) would be the same for any point or object on a tractor in motion. Are you talking rotational speed of the wheel / tire ?. Obviously, the smaller the circumference the faster it has to spin to cover a given distance.

Big tire / slow rev = distance = fast rev / small tire

higgy · Feb 11, 2004

DaneI think that would be rotational speed, a slight slip in the front under 4x4 drive.

The specs must be very close I would think not to have a problem with the drive train.

I have replace diff parts in many 4x4 trucks and they need to be well matched not to bind the drive system, but tire ware, slightly different sizes from the factory etc. will all add to making the rotational speed slightly different so there must be slop built into the drive system.

As these are open diffs in the front the pressure may be released as the power shifts from side to side or when you go around a corner and the inside outside tire rates change. Don't know for sure.

Dane

keeney · Feb 11, 2004

Sorry, your are right, I used the wrong term. I meant the speed at the surface of the tire, not including slippage.

Maybe I should have said "relative tangental speeds of the front tires in comparison to the rear tires, as measured at their respective effective radii under nominal loads and at nominal inflation pressures" if that helps make it any more clear.

Maybe "effective tangental speed"?

Or just "speed"?

- Rick

higgy · Feb 11, 2004

lol very good indead

We do get tangental here as well, on the forms /forums/images/graemlins/blush.gif

del · Feb 11, 2004

I'd just pump them up to what they should be and try it.

There is a certain relief pressure designed in to keep from
bending rods and damaging the steering box.

With the tires properly inflated, even though the fronts
are a little wider it should work as it has turf tires. Turning
a bucket loaded tractor with ag tires is much harder as
the treads really try to dig in.

My oldest tractor will not always turn the tires at a stand
still with ags and a heavy loader but how often do you need
to turn the tires stopped? Just a teensy movement of the
tractor and they turn fine.

The problem here is if it happened JUST with a fluid change
and nothing else. Is there anyway a filter could have been
put in backwards or something installed incorrectly that would impede flow?

Any chance the fluid that was installed (regardless of the
label) was not what it should have been?

Grasping at straws I know...

I know with parts in general you certainly don't always
assume the "new" part is good.

/forums/images/graemlins/smile.gifDE L/forums/images/graemlins/smile.gif

JClark · Feb 11, 2004

The Firestone ag tire web site has a good explanation of the 4WD ratio issues. Sorry, don't have the link right now. My slightly oversize rear tires put me in a lag condition, meaning the front tires are not keeping up with the rears. According to Firestone this is undesirable because of the stress it puts on the transfer case. Makes sense. It doesn't bother me because I only use 4WD when I get stuck. The tractor won't turn very well in 4WD so I stay out of it. I use the differential lock first when one tire starts to spin.

I tend to keep my tire pressures fairly low to minimize the impact on what now seems to be my permanently wet yard. If I have a heavy duty job for the FEL I will pump the fronts up to reduce sidewall flex but otherwise they stay around 20 psi.

My JD advisor called back this afternoon and asked what was going on. I told her I had not heard a word from anyone in over a week and hoped she could tell me. She said her report from the field rep (what I have been calling the regional manager) showed the dealer doing flow tests. She suggested I call the dealer to see when they could schedule the tests. So here we go again.

JClark · Feb 11, 2004

Del,

Yep, happened after the fluid change. All JD fluid and filter per spec. The condition is easy to duplicate, even with a full 750# ballast and just a moderate load in the bucket. Concrete, grass, dirt, gravel, the surface makes little difference. If I drop the ballast to the ground even an empty bucket will cause the problem.

bigpete · Feb 11, 2004

My JD advisor called back this afternoon... 

As frustrating as it may be, your JD advisor is going to be your best advocate in all this hassle. Keep up a good relationship there and they will make it happen. If your dealer remains dumbfounded (or just remains dumb /forums/images/graemlins/mad.gif) your advisor should make the call to the dealer.

Have you written a letter yet? Now is the time. Your advisor will probably have you write it to her. Once I put it in writing, my problem resolution took on a new meaning for the dealer and the RM.

Still out here in the cheap seats rooting for you....

nailerguy · Feb 11, 2004

Hello JCLARK.

I have just finished reading through all 8 pages /forums/images/graemlins/shocked.gif of posts in this thread and there are a couple things I'd like to add to this discussion.

In your first? post you mention that you changed the oil with a low viscosity fluid and that is when you started having the problem. I know for a fact that a lower viscosity fluid will allow more internal pump leakage that will result in a lower system pressure. This slight difference in pressure could be the key difference in your being able to steer the tractor with a load in the bucket before changing the oil and not being able to after changing the oil. /forums/images/graemlins/crazy.gif

In a car engine using regular 10w30 motor oil, my oil pressure at idle was 45 psi cold. When I changed to synthetic oil, it lost 15 psi and went down to 30 psi /forums/images/graemlins/shocked.gif. My point is everything was the same except for the oil. The power steering system uses a lot more pressure than this and the difference between the type of oil that was in the tractor originally and what you put in there to replace it could be where your problem is.

And of course, this all depends on the 2 oils being of different weights to start with, but my money says that they are different. This would also explain why you noticed that the steering wheel would continue to turn when the wheels stopped. The steering wheel is attached to what is basically a hydraulic pump. Internal clearances in the pump are necessary in order for the pump to turn, but that same leakage will allow the pump shaft to turn when the wheels stop. There will be noticeably more leakage with thinner or lower viscosity oils than with thicker or higher viscosity oils.

Now, this being said, There are adjustable and nonadjustable pressure relief cartridges. If yours is adjustable, the dealer should be able to increase the pressure slightly and see if the problem goes away, on the other hand, you could put the original viscosity oil back in the tractor and see if it helps or solves the problem.

I have a Massey Ferguson 4225 utility tractor with 65 engine HP. The tractor has a 72" bucket and with AG tires on the front with 38 Lbs of air, I have very little problem steering the tractor on firm ground with a fully loaded bucket, however, if I drop the air pressure to 25 Lbs, the steering will not operate properly in soft ground. It will start to turn and then stop, to get it going again, I simply move the tractor a little bit and it steers no problem.

Hope this helps in some way, but if not, keep up the posts so we know what the end solution is. /forums/images/graemlins/cool.gif

Nailerguy

JDgreen227 · Feb 11, 2004

BigPete,

No way you are going to convince us that anyone sitting on his nearly new JD has a "cheap seat".

Now, if you had a Kubota or NH instead....... we might believe you.

/forums/images/graemlins/grin.gif

bigpete · Feb 11, 2004

JDgreen227,

My tractor is in a cold, dark shed tonight. I am sitting in my den at my home-office computer desk in a ... you guessed it! /forums/images/graemlins/grin.gif

del · Feb 12, 2004

The low viscosity oil he used is recommended by Deere for
ambient (sp) temps up to 86 degrees.

I don't know if it would make much of a difference though
as the pump itself has far more capabilty then the 2200-2500
psi it's regulated at. I would think it might take .001 seconds
to reach the relief setting with the lighter oil maybe /forums/images/graemlins/smile.gif.

I know with the Kubota UDT/Super UDT the loader/backhoe
operate noticeably faster with the lighter weight oil.

Been there/done that. It is weird that this started with
the oil change though.

Neither Kubota or JD say anything in the manuals about the
need to reset relief pressures using either oil. Will be
interesting to see what the dealer comes up with.

/forums/images/graemlins/smile.gifDE L/forums/images/graemlins/smile.gif

nailerguy · Feb 12, 2004

Del, even though the relief pressure is set the same, it dumps through a sized orifice. And as you said, you noticed that your backhoe and loader worked much faster with the lighter oil. Thats because you can pump thinner oil through a sized orifice much faster and easier than the thicker oil.

Any increase in backpressure with thicker oil may be just enough to cause the steering to work under a load. The time it takes to blow the relief does not make much difference, it's the extra backpressure and reduced pumping losses that will give you the extra push.

An old trick we used to use on worn out automatic transmissions was to add a quart of 90 weight gear oil to improve the pump pressure and make the thing shift until you could scrape up enough money for another tranny! Hey it worked as long as you used the limited slip type. /forums/images/graemlins/grin.gif

I Know I may be splitting hairs, but if it worked before the oil was changed and the oil is now different??? and everything else is except the oil is the same???.

The system has been properly purged of air.
The system supposedly has been checked and is functioning.
Nothing seems to be broken.
A pressure test will tell the story on whether the pump is OK.

My Dad used to tell me to carefully rule out the obvious and whatever was left is usually the answer, this has served me well over the past 43 years and while I could be wrong here, I also could be right. /forums/images/graemlins/wink.gif

Nailerguy