3ph and power steering issues

[kyle35]

I'm new to this forum and 1st time tractor owner 2007 JD 790 2wd. I've allready searched this topic and what I've found is that dirty hydraulic oil and/or filter could be the culprit for the power steering not working correctly. Also my 3ph will not move up or down and I was wondering if the power steering and 3ph problem is related. I bought this tractor last week and haven't been able to fool with it much. Any other things to look out for from my fellow 790 owners will be much appreciated also.

 

[jd110]

Dirty filter, clogged sump screen or a bad pump could be causing both problems among other possibilities. I would recommend draining hydraulic oil, cleaning sump screen, and installing new filter to start. If that doesn't fix it, then some other testing needs to be done to be sure the pump is the culprit.

 

[kyle35]

My tractor has a spin on filter under where my left foot rests and according to my local dealer (salesman) that's the only filter I have. I'll change the oil and filter and post my results within a few days. Thanks for the help. I sure hope it's not a bad pump.

 

[AKfish]

You positive there's not a sump screen (filter)? If that's clogged, even changing the filter (under your foot) will not remedy your problem.

AKfish

 

[beenthere]

The tech manual doesn't mention a sump screen on the 790 when describing changing the hyd. oil filter. I looked, as it is on the same CD that my 4300 is on.

 

[Tx Jim]

Parts schematic shows a strainer(parts key 7) PN-M803024
I'd suggest to clean screen,change hyd filter & hyd oil.

 

[beenthere]

Thanks Tx_Jim
Made me go back to the tech manual and search for that screen. No mention of it when describing hyd. oil filter change, but under Theory of Hydraulic Oil Filter Operation, this schematic shows up with the screen. Failure to not mention it anywhere else, apparently. Also found I'd saved the same one you found in parts, but now can't seem to delete it.

 

[kyle35]

Thanks for the info. I've yet to change the oil and filter I was just going off what a local salesman told me. He told me that my tractor only had a spin on filter. I probably won't be able to change the oil until early next week but l'll post results.

 

[kyle35]

Well I finally changed the hydraulic oil so I had to dig up this old thread. The sump screen/reservoir screen was definitely the culprit. My power steering and 3pt would operate slowly and sorta jerky, but now it's smother and faster than my truck. Also the hydraulic pump would "whine" at times, but after the oil and filter change it makes no noise.

Before

Cleaning

After

 

[Tx Jim]

Thanks for update and I'm glad you got problem solved. Looks if you have a young trainee helping you.:cool2: