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rotate
08-16-2010, 11:52 AM
My Howerd Price mower died on the field on the weekend. I need to tow it back to the barn but because the wheels are hydraulically driven, the wheels are essentially locked. I tried towing it with my tractor and the wheels just drag.

I don't have a service manual so I have no idea how to release the wheels. Is there some bypass valve that allows all the hydralics to become free? If so, where is this typically found?

I have no idea why it died and the engine won't turn over even with boost from my pickup. I'm suspecting that one of the piston has seized :( Here's the picture of it.

http://i7.photobucket.com/albums/y287/rotate85/IMG_0559.jpg

Toolguy
08-16-2010, 12:07 PM
I assume it has a forward, neutral and reverse control lever. Is that in the neutral position? Failing all else, maybe you could put the drive wheels on a dolly like the tow truck guys do with cars so the wheels on the mower don't have to turn.

camdigger
08-16-2010, 12:18 PM
Dolly/trailer the old girl home. If it is a hydro stat that does not freewheel, it is likely a closed center variable displacement system that will not coast.:(

winchman
08-16-2010, 12:20 PM
There is likely a dump or tow valve in there somewhere according to this:

http://webcache.googleusercontent.com/search?q=cache:5li34wOliiUJ:www.deere.com/en_US/golfturf/media/powerpoint/customersupport/2500_hydraulic_system.ppt+towing+a+vehicle+with+hy drostatic+drive&cd=2&hl=en&ct=clnk&gl=us&client=firefox-a

The important part:
"The purpose of the dump (or TOW) valve is to allow the movement of a disabled vehicle or if you want to just push it a short distance, without starting the engine. If an attempt is made to push the vehicle the hydrostatic motors become pumps, trying to pump oil through the system. This creates a hydraulic lock between the motor and pump. To overcome this condition, a dump valve has been installed between the inlet check valves.

The dump valve is a plug that contains a rotating stem which has a flat spade end that fits between the two ends of the inlet check valves. When the dump valve is in the closed position, the inlet check valves are also in the closed position. When the dump valve stem is rotated 90, the flat spade end spreads the inlet check valves to the open position. This allows the oil in the hydrostatic closed loop to by-pass around the inlet check valves inside the pump backplate. The by-passing of oil inside the pump backplate will allow the motor to rotate freely when the vehicle is moved a short distance. The dump valve is intended only for moving a vehicle a very short distance and not intended for towing the vehicle long distances behind a truck or tractor!!"

I'd pay particular attention to the last sentence. Probably dolly time.

winchman
08-16-2010, 12:47 PM
You can download manuals for some Howard Price stuff here:

http://www.howardpriceturf.com/manual.htm

oldbikerdude37
08-16-2010, 01:27 PM
I has to have a bypass valve for short range towing, every hydrostatic mower Iv seen has one. It will still pull real hard as it don't work like neutral, you may even hear the oil flow as you tow it along.

When my cub cadet died I could not push or tow it so I went to our local John deer mower service shop where they work on all kinds of mowers. they told me it was a shaft with a yellow knob you push and hold down, well the yellow knob was gone. Anyway I found the shaft and held it down with my foot and it would freewheel .

I would make a phone call to a good mower service center if nobody here knows or you don't find it.

Too_Many_Tools
08-16-2010, 01:30 PM
Good reason to add another trailer to your collection.

TMT

Too_Many_Tools
08-16-2010, 01:33 PM
The dump valve is intended only for moving a vehicle a very short distance and not intended for towing the vehicle long distances behind a truck or tractor!!"

I'd pay particular attention to the last sentence. Probably dolly time.


I strongly agree.

TMT

The Artful Bodger
08-16-2010, 02:58 PM
If you have a tractor and this field is not too far from where you want to go just jack up the drive wheels and slip planks under them and sledge it home with the tractor.

Deja Vu
08-16-2010, 03:34 PM
You didn't say how far out in the field it was. I'd say you could move/tow it to your shop if not a far distance....that is if your local implement dealer or repair shop notes that it indeed has a bipass valve and says it is okay.

rotate
08-16-2010, 03:49 PM
Thanks everyone for your input.

The mower is about 100 feet from the barn, where I'll park it until next year.

I noticed that there are 3 hydraulic connections to each wheel. The third one is a flexible rubber hose, so I'm guessing that it's the lower pressure return line, and the other two are for forward and reverse. Can I just remove the return line and will that allow the wheel to freely spin?

I'll try to drain the hydralic fluid before doing this, but is there a reason why I shouldn't do this?

digger_doug
08-16-2010, 03:56 PM
Thanks everyone for your input.

The mower is about 100 feet from the barn, where I'll park it until next year.

I noticed that there are 3 hydraulic connections to each wheel. The third one is a flexible rubber hose, so I'm guessing that it's the lower pressure return line, and the other two are for forward and reverse. Can I just remove the return line and will that allow the wheel to freely spin?

I'll try to drain the hydralic fluid before doing this, but is there a reason why I shouldn't do this?


Well no, the third should be the "case drain" to take care of leakage
from the motor. When rolling the thing, one high pressure hose will
want to suck oil from the source (thru the variable displacement pump,
which it can't really doo) and the other will try to pump oil back thru the
cotrol (which in a closed center system is closed)

Why not unhook both high pressure lines, forget the low pressure case
drain.
A little oil will be pumped out of the motor in towing, it will suck air in,
but the motor will not pump dry thru towing, so the motor will be
oiled (sort of)

Guido
08-16-2010, 04:04 PM
DiggerDo X 2-----No biggie-------

--G

oldbikerdude37
08-16-2010, 04:09 PM
Thanks everyone for your input.

The mower is about 100 feet from the barn, where I'll park it until next year.

I noticed that there are 3 hydraulic connections to each wheel. The third one is a flexible rubber hose, so I'm guessing that it's the lower pressure return line, and the other two are for forward and reverse. Can I just remove the return line and will that allow the wheel to freely spin?

I'll try to drain the hydralic fluid before doing this, but is there a reason why I shouldn't do this?

That will work, just tape stuff up With rags and tape at least to keep it clean/er. I bet once you get to the barn you will find the bypass.

Best of luck getting it fixed, A mower like that is not cheap, its a shame its not under its own power.

The Artful Bodger
08-16-2010, 04:17 PM
Only 100'? All the more reason to put a couple of planks under and skid it home, there is little point in compromising the hydraulics by opening the system when there is really no need.

Depending on the tractor you might even be able to lift the drive end and creep to the barn with it.

oldbikerdude37
08-16-2010, 05:01 PM
Only 100'? All the more reason to put a couple of planks under and skid it home, there is little point in compromising the hydraulics by opening the system when there is really no need.

Depending on the tractor you might even be able to lift the drive end and creep to the barn with it.

I agree there too, it would piss me off bad and it would be in the barn. Its not a Nascar, no worries of flat spotting the tires, I would drag it home and let my blood pressure go down.

radkins
08-16-2010, 06:03 PM
Thanks everyone for your input.

The mower is about 100 feet from the barn, where I'll park it until next year.

I noticed that there are 3 hydraulic connections to each wheel. The third one is a flexible rubber hose, so I'm guessing that it's the lower pressure return line, and the other two are for forward and reverse. Can I just remove the return line and will that allow the wheel to freely spin?

I'll try to drain the hydralic fluid before doing this, but is there a reason why I shouldn't do this?



NO! That will NOT work, that is not a return line, it is a case drain do not remove it because it will not relieve the pressure. Removing it will not in itself cause any harm and will leak only a relatively small amount of oil but damage can still occur from trying to move the wheels while they are still locked. All that line does is relieve the case pressure from normal internal leakage during o0peration, you still need to find that by-pass valve.


On a hydro-stat system you do not have a return line as such the fluid simply switches directions and both lines alternatively switch from low to high pressure during forward/reverse maneuvers.