Proud new owner..................422 arrived today

RegL · Jun 6, 2004

While we are talking about mowing on hills, here's one that has me scratching my head. I was brush hogging a small ski slope today with the 1430. Not all that steep, although being wide open, I suppose it could be steeper than it looks. Anyway, I make 3 or 4 passes up and down with no problem. Than I start spinning the tires and can't make it all the way up. I even tried shutting the mower off and lifting the deck and I couldn't make it up, even where I had already mowed and my traction seemed to get worse the longer I was mowing. The same thing happened last year and I blamed it on the turf tires and wet conditions but this year I have a brand new set of bar treads on it. Is it possible that as the hydraulic oil get heated that it gets distributed to the wheel motors differently like maybe all gets pumped to the spinning wheels?

This is probably way out there, but I wonder if there is such a thing as flow sensors that control a valve in each wheel circuit to keep equal flow to all wheels all the time. That might be a little to techy for a Power-Trac but it's getting embarrassing having to get someone with an ag tractor go in to finish a job the PT couldn't. LOL!

SnowRidge · Jun 6, 2004

RegL, which wheel(s) were spinning? I would think it would have to be all of them.

I don't know how a 1430 is plumbed, but the 425 hydraulic diagram shows pairs of wheel motors in series. It is not detailed enough to show which wheel is in series with which, but I am assuming that the right rear is in series with the right front, etc. I assume that, since it would be impossible for both wheels on the same side to be off the ground at the same time (except when falling off a cliff, of course /forums/images/graemlins/shocked.gif), thus ensuring movement as long as one wheel held traction.

In any event, plumbing two wheel motors in series would act as a limited slip "differential." When I'm going through a really wet area, I often notice one of the wheels slip slightly, but it never spins much faster than it would if it had full traction.

It is possible your machine is plumbed incorrectly?

SnowRidge

RegL · Jun 6, 2004

( RegL, which wheel(s) were spinning? I would think it would have to be all of them.

I don't know how a 1430 is plumbed, but the 425 hydraulic diagram shows pairs of wheel motors in series. It is not detailed enough to show which wheel is in series with which, but I am assuming that the right rear is in series with the right front, etc. I assume that, since it would be impossible for both wheels on the same side to be off the ground at the same time (except when falling off a cliff, of course /forums/images/graemlins/shocked.gif), thus ensuring movement as long as one wheel held traction.

In any event, plumbing two wheel motors in series would act as limited slip "differential." When I'm going through a really wet area, I often notice one of the wheels slip slightly, but it never spins much faster than it would if it had full traction.

It is possible your machine is plumbed incorrectly?

SnowRidge

That's interesting. I'll check my book. I can deffinitly get one wheel spinning and the others not turning at all. While mowing this slope going forward one or both front wheels were spinning. When trying to back up, one or both back wheels were spinning. After hereing who your tractor acts I suspect that I do have a problem. One of the reasons for buying the PT was I figured it would be better on hills than my cut so I would sure like to get this figured out. Also can't figure why traction is better when tractor is cold. As a matter of fact, I have no traction problems in winter. One year is up in Aug. so I better get cracking. Thanks and keep the ideas coming. )

Bob999 · Jun 6, 2004

Than I start spinning the tires and can't make it all the way up. I even tried shutting the mower off and lifting the deck and I couldn't make it up, even where I had already mowed and my traction seemed to get worse the longer I was mowing. The same thing happened last year and I blamed it on the turf tires and wet conditions but this year I have a brand new set of bar treads on it. Is it possible that as the hydraulic oil get heated that it gets distributed to the wheel motors differently like maybe all gets pumped to the spinning wheels?


My guess would be that the surface conditions are changing as you work--You indicate that wheels are spinning so power is not at issue, rather the issue is traction. I know that on the steep slopes I mow the moisture conditions vary depending upon shade, slope, and orientation of the slope to the sun. I have one area that is nearly always difficult because it is damp.

The moisture conditions could wet your tires and cause a build up of "slime" from newly cut grass and moisture that results in a degradation of traction.

Clarke · Jun 6, 2004

My 425 has the Kohler engine and I operate it at full throttle most of the time. When mowing down hill and using the wheel motors in reverse and you stall the mower adding more reverse to back up the slope sometimes will stall the engine. You can put the parking break on, turn off the PTO or lift the mower. My reaction time is getting better with seat time.

sg

Clarke · Jun 6, 2004

Are all your wheels spinning. Before I purchased the PT I was reading a thread in another site discussing the PT and the traction and wheel motor plumbing. Apparently when you get a wheel spinning you can loose power to the other wheel and loose traction. This was one of the cons to the PT. I'm not a good hydralic person but trying to learn. I do know the fluid will take the path of least resistance and this might be the spinning wheel.

sg

J_J · Jun 6, 2004

In reference to stalling an engine. While cutting on level ground, max engine speed is necessary to provide full hydraulic pump volume to the PTO for maximum cutting tip speed. If you decrease engine speed you lower the pump gpm, and forward speed and decrease your chance of getting a good cut.

In reference to ground speed on a level field, you should use the best ground speed for the grass that you are cutting . If you try to go up an incline, at the same speed, you may very well stall the engine. Why, because you now have increased the load on the engine from rolling speed to lifting speed, and the response for most people is to add more speed by pressing down on the pedall. This is not good for a hydraulic system. What you should do is to let off on the pedal and go up hill slower. Try it and I think you will find this to be true.

I you can barely make it up hill, you might try shutting of the PTO. this decreases the load a little bit.

If you disagree, fine. Let me know what you think.

SnowRidge · Jun 6, 2004

(In reference to ground speed on a level field, you should use the best ground speed for the grass that you are cutting . If you try to go up an incline, at the same speed, you may very well stall the engine. Why, because you now have increased the load on the engine from rolling speed to lifting speed, and the response for most people is to add more speed by pressing down on the pedall. This is not good for a hydraulic system. What you should do is to let off on the pedal and go up hill slower. Try it and I think you will find this to be true.

I you can barely make it up hill, you might try shutting of the PTO. this decreases the load a little bit.

If you disagree, fine. Let me know what you think.) 

J_J, I think you have me confused with another poster. I have never suggested that anyone should increase pedal when the engine is overloaded--quite the opposite, in fact. The pedals are the equivalent of a transmission range control, not a throttle.

SnowRidge

RegL · Jun 6, 2004

( Are all your wheels spinning. Before I purchased the PT I was reading a thread in another site discussing the PT and the traction and wheel motor plumbing. Apparently when you get a wheel spinning you can loose power to the other wheel and loose traction. This was one of the cons to the PT. I'm not a good hydralic person but trying to learn. I do know the fluid will take the path of least resistance and this might be the spinning wheel.

sg )

This post might be kind of long but I just did some traceing and experimenting and found the results interesting being I don't know alot about hydraulics.

First of all Clarke, what you explained about one wheel spinning and loosing power to the rest is the appearance you get, but in fact, I think just the opposite is happening. I think that as you load the wheel motors ( as in driving up a steep slope ), you get to the point where you stall all the motors until one breaks traction and spins. The reason I say that is that I traced the plumbing, and as Snowridge stated before, the front and rear wheels on each side are plumbed in series. Obviously, both motors on that side would have the same flo rate which may be enough to turn the wheel with less traction but not enough to overcome the resistance on the wheel that has good traction. Like two waterwheels in the same stream, one trying to turn a heavy load and the other with no load attached.

Now for the lab work. I chained the PT by the rear hitch to the big old Chinese tractor. Set the PT at half throttle and trammed forward. Sure enough, the front right wheel starts digging a hole and the other three don't turn. went to full throttle and got the right front going pretty fast and the left front about half as fast. Put the treadle all the way forward, engine bogs down and rear wheels still have to much traction to overcome. Engine would have stalled before the rear wheels broke loose. I took it one more step by setting the parking brake. This locks only the front wheels. Trammed in reverse, and the left rear wheel starts spinning.

So, My observations tell me the 1430 doesn't have mechanical problems but it does have limits and that's a hard one to swallow.LOL! Me thinks more horse power to spin all four without stalling would do the trick. ha ha

PTRich · Jun 6, 2004

I run my tractor at full throttle almost always. Works good for me. The hydralics always have the same speed. The hydralics work slower at lower engine speed.