John Deere 1020 with poor hydraulic pressure

[J_J]

What is the control valve controlling?

 

[buickanddeere]

I would suggest to put a hyd pressure gage in the system and check to see if the pump is still capable of making that pressure.

Your relief need may need to be reset.

There is no relief valve on the closed center pump. There is a stroke control valve that de-strokes the pump when system pressure reaches 2250psi.

 

[buickanddeere]

You need to verify there is no high pressure oil if flowing when the PS, rockshaft, scv and loader is not being used.
Oil pressure is low either because of a high pressure side leak or low flow from the trans pump to supply the front pump. Or the stroke control valve spring is weak and/or the valve/seat is worn. Dial the standby pressure up to 2300psi.
There is a priority valve that stops oil flow back to the scv,rockshaft and loader if properly plumbed. To preserve operation of the power steering if there is a partial hydraulic system failure.
Front pumps do eventually wear out or break but.....................they are replaced as a wild guess probably 100 times too often. Instead of solving every high pressure leak or low supply flow from the trans pump.

 

[snowman69]

The loader cylinders and bucket.

 

[J_J]

So you are saying the system can build up pressure, but the loader can not develop the pressure or the flow is going somewhere else.

Have you checked the cyl for proper operation. Try connecting the cyl to another source/pump/tractor and see if they can develop the advertised pressure.

If the cyl are known good cyl, then the loader valve is bad.

 

[snowman69]

I will check the PS and rocker this week. I am going to hook up a gauge to the line and see what it is doing. I do not know where the adjustment for the standby pressure is. I plan on trying to find a service manual to look at this week.

 

[Tx Jim]

snowman69
HAVE YOU CHECKED/CLEANED SUMP SCREEN??????????? You keep answering you've changed hyd filter but a clean sump screen is just as important to the operation of this tractors hyd system as the hyd filter. Is your tractors serial number within or """above""" this range(010001-045199)?? The SN is on RH side of trans case under the seat. Have you tried tightening stroke control valve to increase stand-by pressure to the factory setting of 2250 psi?

 

[Tx Jim]

I do not know where the adjustment for the standby pressure is. .

Parts key #29 CW to raise pressure.