Wrong hydraulic oil causing too much resistance in hydraulic pump?

[TimBuck2]

Solved.

Langanobob nailed it. I took the mower off of jack stands and ran it on the ground. The hydraulic pump(s) made ugly noise for about 5 seconds, but then everything is started working normally.

Apparently hydraulic motors (or at least my set up) can't be "free wheeling" otherwise pressures build up in the wrong places.

Good thing to know!

Thanks again.

 

[dodge man]

I think I’d stick the old hydraulic filter back on and try it. Just a guess but wrong or defective filter.

 

[TimBuck2]

Parking brakes aren't engaged are they?

They were not, but believe me, I have done dumber things than that

 

[oldnslo]

Solved.

Langanobob nailed it. I took the mower off of jack stands and ran it on the ground. The hydraulic pump(s) made ugly noise for about 5 seconds, but then everything is started working normally.

Apparently hydraulic motors (or at least my set up) can't be "free wheeling" otherwise pressures build up in the wrong places.

Good thing to know!

Thanks again.

Solved.

Langanobob nailed it. I took the mower off of jack stands and ran it on the ground. The hydraulic pump(s) made ugly noise for about 5 seconds, but then everything is started working normally.

Apparently hydraulic motors (or at least my set up) can't be "free wheeling" otherwise pressures build up in the wrong places.

Good thing to know!

Thanks again.

Where the wheels running at full speed when on the jack stands? Just curious since logic would say if everything was full of oil and stayed full of oil it should not matter if spinning free or not.

Glad it is working for you now.

 

[TimBuck2]

Where the wheels running at full speed when on the jack stands? Just curious since logic would say if everything was full of oil and stayed full of oil it should not matter if spinning free or not.

Glad it is working for you now.

When it was on the jack stands I would engage the hydraulic valve control for either wheel about 1/8 or less of the total lever/throw distance and the wheel would start spinning. It may have been spinning about full speed by then, but it was hard to tell.

Then as I moved the valve lever further there would be enough torque at the hydraulic pump that the engine would bog heavily, and by half way through the valve lever throw distance the engine would slow down and died in just a few more seconds.

If anyone has any ideas how running the hydraulic motors with no resistance / back pressure resulted in so much pressure and torque int he system I would be very curious.

 

[oldnslo]

Tim
I have no clue on how running wheels in the air would cause excessive pressure.

 

[Bentrim]

Have you bled the pumps? Raise the wheels off the ground open the "push with engine off valves" usually a hex head with a hole in it. Start and run engine while moving the control handles forward and reverse slowly.
Reason: The pump to motor circuit is a "closed" system, air can get trapped in this circuit and destroy the pump and motor. Opening the bypass screw allows the air to get out of this circuit. Check operators manual may explain the particulars.

 

[Flogger]

Air in the system. Open freewheel valves and work the sticks forward to reverse a half dozen times. Close the valves and try it again. Repeat until it runs smoothly. I would definitely put the 20w50 back in it. When you get it heated up the hydraulic oil will be like water.