John deere 6420s power beyond

[manttys]

Hello guys. I am from Lithuania and nobody seems to be able to help me on the forum, so here i am to give it a try in your forum Excuse my English.


I have John deere 6420s tractor and want to connect a McHale fusion baler to it. The latter has an independent hydraulic control unit and is recommended to use via power beyond with load sensing. AL 161388 Spacer with adjustable LS bleed (POWER BEYOND) is installed on my tractor. I have connected the necessary couplers to it, however, the baler doesn't work properly. The pressure gauge basically shows only standby pressure even though pilot line is returning oil signal from the baler.

Having activated any of SCV units (not plugged), I can see that pressure builds in oil supply line but still no functions on the baler works.

Can it be that the shuttle valve plate between the rockshaft and the power beyond plate is missing (e.g. "B" in the picture), it was changed a couple of years ago due to some failure. Perhaps the mechanic did not add it. As far as I understand, in this case the oil pressure for the power beyond pressure line would not build as it is. How could I check if the valve is missing? Shuttle valves seem to be between all sections in order to transfer oil pressure where it is needed.


Thank you for any help

 

[Tx Jim]

:welcome: to TBN I understand JD's older closed center hyd's(55 series & below) but not the closed center pressure compensated such as your 6420. By chance does the Mchale baler have open center hyd valves?? Maybe another TBN member can help you.
Jim

 

[manttys]

:welcome: to TBN I understand JD's older closed center hyd's(55 series & below) but not the closed center pressure compensated such as your 6420. By chance does the Mchale baler have open center hyd valves?? Maybe another TBN member can help you.
Jim

It can be set to open center by adjusting a screw. When set to open center i do not plug load sensing hose and everything works fine constantly pumping the oil. But they recommend using closed center load sensing; and in addition it helps to save power while pumping oil only when needed

 

[Tx Jim]

It can be set to open center by adjusting a screw. When set to open center i do not plug load sensing hose and everything works fine constantly pumping the oil. But they recommend using closed center load sensing; and in addition it helps to save power while pumping oil only when needed

I attended JD sales meetings in the 60's-70's getting lectured to about the fuel savings of closed center hyd's. Now in my later life I have one question. How much fuel does it take on an open center hyd system pumping hyd oil at almost zero pressure which is what is happening until a control valve is activated?????

 

[manttys]

I attended JD sales meetings in the 60's-70's getting lectured to about the fuel savings of closed center hyd's. Now in my later life I have one question. How much fuel does it take on an open center hyd system pumping hyd oil at almost zero pressure which is what is happening until a control valve is activated?????

citation from mchale manual: "Although it is possible to operate the fusion with a load-sensing system via. tractor auxiliary spools, i.e. continuous oil flow (control valve is set to open centre set-up and flow is set to lit/min. from the tractor), McHale do not recommend operating the Fusion in this set-up, as controlling the oil flow is too variable from one tractor to another, and there is also a 20 kW pto power loss with it's associated over-heating of the oil."

IMHO 20 kw pto loss is very overestimated. Honestly, even going uphill and engaging oil flow didn't seem to have much impact on tractors performance. But there is another issue - when one spool is activated, I can't pick up baler's picup via second spool. The first one takes all the oil flow. So the power beyond application would also help me.

 

[jasong123]

I can't comment on the baler but the 6420 may have a missing shuttle as you suggested. If the shuttle is missing you can test for it in the following way:

1. plug the LS port on the PB section
2. Open the adjustable LS bleed (to bleed the port)
3. Select another section to a dead port. -> if the pump pressure goes up, the shuttle is fitted, if not, the shuttle is missing.

Does the baler have a Supply, Tank and LS line?