4020 power steering cuts out

[Clodhopper Pete]

I bought a 4020 about a month ago. A couple of times now while backing up a hay wagon the power steering has cut out. Other wise the ps hasn't given me a bit of trouble. My neighbor told me the 4020 he had did the same thing sometimes. Is that a common problem on that tractor, and what needs to be done to fix it? Thanks for any suggestions.
Pete
 

[Tx Jim]

1st thing I'd suggest to do is check stand-by pressure. It should be 2250 psi. 4020's don't have a history of intermittent power steering.
 

[tim s]

What year is it and what transmission?? If the transmission pump is weak it will not keep enough flow going to the front pump as you feather the clutch while backing, also could be a high pressure leak to sump causing to much reserve pressure oil to get away...
 

[David G]

I have seen this issue immediately after starting when the check valve leaks from front pump back into the transmission.
 

[Clodhopper Pete]

It is a 1970 syncro.
 

[Tx Jim]

Tim hit the nail on the head. When backing trailer every time clutch is depressed trans pump stops pumping oil to frt pump.
 

[tim s]

It seems that the console models are worse for this, a lot of times it's the PTO operating valve leaking through...
 

[AJB-830]

Tim,
Was reading this today. A friend of mine has a 3020 Syncro Transmission with the same problem. He had the transmission pump replaced in spring and now the problem is back. Any clue as to what might be wrong or could it be that a bad pump was installed. Otherwise it will have to be hauled back to his JD dealer. Thanks. Al
 

[tim s]

Al, I have had this same thing happen and it can be tough to find the reason, There is a way to install a check valve down on the left rear side where the charge oil leaves the case (It has been talked about on here with the things you need to do it), this can help, then isolate components one at a time to try and find if one of them is letting standby oil pressure escape too quickly. The thing to think about is the charge oil supply stops as you press the clutch pedal down,so the reserve is what is in the oil cooler, or on console models the storage tank out front.if the trans pump is bad it will let oil barf back past the worn gears, plus not supplying a strong charge to start with, if this is freshened up and the problem still exists a component such as the brake valve ,Scv,steering,could be leaking through using up the reserve oil supply as you feather the clutch while backing, or edging forward.
 

[Tx Jim]

I'll add to what Tim stated to check each hyd function with a laser thermometer to see if one component is getting hotter than the rest of them.
 

[AJB-830]

Tim S, Tx Jim,
Thanks for your replies. My friend will probably be taking his 3020 back to the JD dealer to see if they can find the problem. We are not that experienced in fixing hydraulic problems or have the tools. Will let you know what they find. Al