Another HST Transmission Problem

[Sergei]

My 2815 hst has 557 hrs on it and now it won't move forward or reverse and I discovered that power steering doesn't work either. Tried Installing both filters and new Chevron hydraulic fluid, but that didn't help at all. Was working fine before putting it always.
Also the FEl , 3 point, PT0 all work

Anyone have any thoughts on this problem? it

 

[k0ua]

My 2815 hst has 557 hrs on it and now it won't move forward or reverse and I discovered that power steering doesn't work either. Tried Installing both filters and new Chevron hydraulic fluid, but that didn't help at all. Was working fine before putting it always.
Also the FEl , 3 point, PT0 all work

Anyone have any thoughts on this problem? it

You would have to look in the workshop manual, BUT many tractors use the second section of the main hydraulic pump for power steering operation and also use this fluid flow for the hydrostat charge pump which supplies the "makup oil" that leaks internal to the hydrostat main pump. Some hydrostats have their own built in charge pump, but many of these tractors do not. Without a charge pump flow, your hydro won't go, and without power steering flow from the secondary portion of your main hydraulic pump the steering won't work either. The 3pt and Fel would still work fine as the main pump flow is still working. You need to test the flow from your secondary section of the main hydraulic pump that runs off of your cam.

 

[Sergei]

Looking at the service manual under Hydraulic Pumps I've got a unit located on the engine that has oil pump 1 and also oil pump 2, sounds like what you described. 2 goes to the power steering. And 1 is for Hydraulic Cylinder. Japanese manual are really fun to read and understand.

Thanks for the help

 

[k0ua]

Looking at the service manual under Hydraulic Pumps I've got a unit located on the engine that has oil pump 1 and also oil pump 2, sounds like what you described. 2 goes to the power steering. And 1 is for Hydraulic Cylinder. Japanese manual are really fun to read and understand.

Thanks for the help

If you have circuit diagrams in the manual, see if you have a circuit from pump 2 section that goes to the charge pump input on the hydrostat. It should be around 200 PSI. maybe a bit more. Possibly no pressure being developed for some reason (internal leak) or no fluid flow coming from the pump. Remember these pumps DO NOT make pressure, they make flow. Pressure develops when the flow meets resistance to that flow.

 

[Sergei]

Final found a diagram on the John Deere forum about a 4200 tractor that identify the components and colored the flows. Makes understanding how it works. The Mahindra manual didn't show anything, just a plain schematic.

 

[Sergei]

This tractor is going to fight me every inch that it can. Trying to check the high pressure before working on the pump just to be sure of the problem and sure enough the plugs are using metric hex, only have standard sizes. Didn't have a 5mm hex socket so off to the farm store to get one, but as usual they didn't have one. Got allen wrench instead and can't break either one loose even after soaking with PB blaster,so most likely rusted. Needless to say not a happy camper today.
Question for anyone with either a 2815 or 3215 series and have you removed the plugs. I'm assuming that they losen counter clockwise,but being Japanese I could be wrong.

 

[Sergei]

Removed pump and the shaft is worn and also the inside gears. I'm guessing the pump frozen, but I'm not sure why there appears to be rust in the inside gear.

 

[k0ua]

Water in there somehow? How did that happen?

 

[Sergei]

Looks like rust, it dry inside and powdery where the shaft goes into the housing and I can remove it. The bearing has some bad spots which probably caused the failure. Not sure if it's a dry fit or lubricated. My biggest question yet to be answered is whether the inside grooves are gone. Going to check with local companies for scarp shaft to check.

 

[Sergei]

What I thought was a bearing looks more like oil seal on the shaft. The more I play with it there's has to be wear in the housing for the shaft. When I first tried turning it after removing it I found it was hard to turn.