Closed Center Systems

[MNBobcat]

MNBobcat
From reading your other post in JD forum I determined your 3020 is a '64-'68 model which didn't have the option of PBY but could be plumbed by teeing into hyd supply line by brake valve and returning oil to ether rockshaft return line or ported hyd filter cover as shown in attached photos.

I think that has already been done when the control valve on the fender was added for the front end loader. I have the line coming off the hydraulic filter cover that you show in the first photo.



Redneck answered my question which was trying to get my head around how you could dead-end the hydraulic flow and not have problems. I was thinking about it akin to having your well pump running with nowhere for the water to go. Usually that is bad for a pump and builds heat and pressure.

I do need to figure out some way to increase the lift capacity on the front end loader. Don't know if that means more hydraulic pressure and/or different cylinders. I tried to lift 2550 pounds yesterday off a flat bed with no luck. Once the weight was on the ground I could lift it a bit but higher up it wouldn't lift it.

 

[Tx Jim]

1st & simpllest thing to do is check stand-by pressure by plugging a 5000# gauge in a QD. I suggest 2350 psi.

 

[J_J]

I think that has already been done when the control valve on the fender was added for the front end loader. I have the line coming off the hydraulic filter cover that you show in the first photo.

View attachment 439613

Redneck answered my question which was trying to get my head around how you could dead-end the hydraulic flow and not have problems. I was thinking about it akin to having your well pump running with nowhere for the water to go. Usually that is bad for a pump and builds heat and pressure.

I do need to figure out some way to increase the lift capacity on the front end loader. Don't know if that means more hydraulic pressure and/or different cylinders. I tried to lift 2550 pounds yesterday off a flat bed with no luck. Once the weight was on the ground I could lift it a bit but higher up it wouldn't lift it.

Increase pressure will provide an increase in lifting power, but at some risk.

Larger cyl would definitely increase the lifting weight, but you might need more weight on the back.

Tilting the load back over the bucket pins will transfer the center of gravity.

 

[Tx Jim]

Increase pressure will provide an increase in lifting power, but at some risk.

Increasing stand-by pressure on a JD 3020 to 2350 psi involves very little extra risk.

 

[MNBobcat]

Increase pressure will provide an increase in lifting power, but at some risk.

Larger cyl would definitely increase the lifting weight, but you might need more weight on the back.

Tilting the load back over the bucket pins will transfer the center of gravity.

Is there a way to increase the stand-by pressure? I didn't know if there was an adjustment or if it meant swapping something out, etc. Would appreciate hearing how I would increase the pressure if you happen to know.

My rear tires are filled with Chloride so weight shouldn't be an issue.

 

[Tx Jim]

Stroke control adjustment screw can be accessed under frt of tractor. Loosen lock nut then screw in the screw(parts key 37) while observing a 5000# gauge plugged into rear remote with remote control lever activated. As I previously stated I'd set stand-by psi @ 2350 if it was my tractor.

 

[J_J]

The tractor pressure setting is there for a reason, be it the limit of the cyl, hoses, mechanical parts, strength of the metal parts, etc.

If Jim says it s no big deal, go ahead and take your chances, and if it blows up, or burst, etc,, call Jim.

A 2 in cyl 1 in shaft and 2500 psi will lift about 7854 lbs.

A 2 in cyl 1 in shaft and 3000 psi will lift about 9425 lbs.

The potential is there if you can get away with it.

 

[Tx Jim]

J_J
100 extra psi will not hurt a JD 3020 hyd components or attachment but will increase FEL lifting a little bit. BTDT several times as a former JD dealer service manager. 2350 is the very maximum I'll recommend,any more psi and one takes a chance of blowing seals. Besides MNBobcat by installing gauge may determine that his tractor's stand-by pressure is nowhere near the factory setting of 2250 psi.
Jim

 

[MNBobcat]

I only have 2,000 psi. I've been crawling around under the tractor and can't find the stroke control. Do you have any more info on where I can find it? Is it in front of the engine somewhere?

The dealer said it should be 2350 psi.

My manual says there are selective control valves that control the rate of operation for each remote. 2 control valves located by removing the left side shield and reaching under the hood. But I'm not clear if that is different than the stroke control?

 

[MNBobcat]

Found it. I called a friend of my dad's who has been working on John Deere's forever. Old farmer. He clued me in that the pump runs off the front of the crankshaft and he thought it was right by the front axle. Sure enough! I ended up setting it at 2,300. It got dark on me and I called it good.

Thanks again!