JD 3520 brand new ....FELoader and top and tilt Bleeds down.(drifts down)

[cartod]

So you are saying I don't just have to live with a droopy bucket, and this is curable?

 

[Wnc3]

yes, it is fixable.

 

[Wnc3]

update:

I picked up the machine and the hydraulics will hold much better. However, it will not hold the bucket up over night which mean there is still seapage in the valve body. So that is just how it is....According to one of the mechanics, the older jd's had a diffent style valve that had a more positive shut off and a different style valve. Just what he said...
I know that some spool valves will hold for a long time, so not sure what is different about these spool valves, but I would guess it has to do with the precision of how they are made and posibly O rings and seals.
The hoses to the diverter were also plumbed backwards and the result was when the tractor was turned off/on it would default to the rear svs valves and not the Front loader. That is fixed and makes much more sense...

 

[jeffster]

Just as a point of reference I have a 2007 3520 and mine has no seepage that I have ever noticed. Absolutely doesn't do it while working and I always relieve pressure off the FEL and 3pt for safety reasons (i.e., nothing hanging in the air for people/pets to get trapped under), but I do know that I have had the FEL in the air for a few hours while I was skinning an elk and it never drooped.

 

[arlen4720]

update:

I picked up the machine and the hydraulics will hold much better. However, it will not hold the bucket up over night which mean there is still seapage in the valve body. So that is just how it is....According to one of the mechanics, the older jd's had a diffent style valve that had a more positive shut off and a different style valve. Just what he said...
I know that some spool valves will hold for a long time, so not sure what is different about these spool valves, but I would guess it has to do with the precision of how they are made and posibly O rings and seals.
The hoses to the diverter were also plumbed backwards and the result was when the tractor was turned off/on it would default to the rear svs valves and not the Front loader. That is fixed and makes much more sense...

I agree that some of the older tractors held allot better. There isn't any seals or o-rings in a spool valve. I's just a precision machined metal-on-metal seal.
I too don't know what is different. One thought I had was possibly modern hydraulic oil may be lower viscosity???.
As a kid, I remember a tractor that we would put in the machine shed for the winter, and we would raise the loader up to clear another tractor. It would sit there all winter and not bleed down. If you look on the "other forum", in the technical library, there is a document with the published accepted leakdown rates from JD. For the 300cx its 2 or 3 inches per hour. My 400cx MAYBE will drop 2 or 3 inches overnight, but It's only got 80 hours on it.

 

[MtnViewRanch]

I agree that some of the older tractors held allot better. There isn't any seals or o-rings in a spool valve. I's just a precision machined metal-on-metal seal.
I too don't know what is different. One thought I had was possibly modern hydraulic oil may be lower viscosity???.
As a kid, I remember a tractor that we would put in the machine shed for the winter, and we would raise the loader up to clear another tractor. It would sit there all winter and not bleed down. If you look on the "other forum", in the technical library, there is a document with the published accepted leakdown rates from JD. For the 300cx its 2 or 3 inches per hour. My 400cx MAYBE will drop 2 or 3 inches overnight, but It's only got 80 hours on it.

I'm guessing that you have never had a prince spool valve apart. There are seals at each end. Now what all those seals do I do not know. I do know that after I gave up on replacing the o'rings after several times and went to actual lipped seals, I have not had any more leaks or leak down to worry about.

 

[arlen4720]

I think those seals are just to seal the plungers. They don't (thankfully) have anything to do with sealing the internal ports from one another. I guess I worded that poorly. I was speaking in the context of internal leakage, not leaking of fluid to the outside world.

 

[MtnViewRanch]

You are right as far as they don't take any real pressure, but the fluid leaks out plenty fast when they are bad, and thus causing cylinders to drift down for a very poor and messy situation.