DK65 Hydraulic Help needed

[pinus]

Need some help still on my 2003 DK65 Hydraulics. At RPM below ~1400 you the steering or loader will not work. You can rev it up above 1400 rpm and things kick and go mostly. However you can pull one of the rear remote levers at the same time below 1400 rpm and as soon as you hear the slightest squall sound the steering and the loader will work.
Things done so far include replacing the old worn pump, replaced MLS valve o rings and cleaned, cleaning the steering valve on top of the pump (seems like few models are setup this way), replaced fluid and filters twice, and for a short time rigged up a hose to bypass the filters and most of the steel tuber/orings on the suction line to the pump trying to insure we are not sucking air.

I bought a used pump which I'm guessing how good it is. Question is if the pump is really good and also we question the steering pressure valve that sits on top of the hydraulic pump. Any suggestions where to go to from here? Thinking of hauling it a dealer that has flow meter testing capabilities, etc.

 

[pinus]

Also there has been times cracking a hydraulic line or feeling a pressure line there appears to have air or agitation in the system. Can a worn pump cause this effect either by agitation or getting air through shaft seals/bushings? This will make a fellow crazy!

 

[oldnslo]

Does this pump have a single set of gears or two sets of gears AKA a double pump.

If single set of gears with priority steering valve then the priority steering can and will send x amount of flow to steering all the time. Is that amount equal to around 1400 RPM.

Do you have a hydraulic schematic for this tractor.

 

[Billrog]

Diverter valve ?

 

[pinus]

Does this pump have a single set of gears or two sets of gears AKA a double pump.

If single set of gears with priority steering valve then the priority steering can and will send x amount of flow to steering all the time. Is that amount equal to around 1400 RPM.

Do you have a hydraulic schematic for this tractor.

I don't have a schematic for the hydraulics but a guy working on it for me does. There is some design changes that have moved valves without noting it. It does only have a single sprocket on the end of the pump shaft. Pump is a casappa 66614680. I did learn from my mechanic today he could pressure air into the back filler tube and the tractor hydraulics would work at an idle. Makes me wonder if its just not a worn pump that won't pickup until hitting 1400 rpm