Loader Question 4020

jonwymillj · Jul 24, 2015

I have a 46A on my 4020(some day I want to upgrade to a 148 or 158 but this came on the tractor) with a prince pump on the mid pto. And a cross three spool valve. My problem is that when I pick up a load of bales it wont go more than a couple of inches up or tilt back at a time. When it is empty it almost always works fine. Sometimes when I just grab 2 bales it lifts fine and other times it doesn't. They are close to the same weight of bales. I switched pumps and tried aonther pump no change. I can't see any bad or pinched hoses. I just replaced the high presure from the pump to the valve. My guess is the seals on the spools are starting to leak bye??? I have noticed the loader getting weaker and controls getting worse over the winter plowing snow. Do you guys think I am on the right track? I tried calling Cross to day but did not get through try again next week. Thanks

Bob · Jul 25, 2015

There's NO seals on the spools 'cept at the external ends, to keep oil from leaking out, they are a precision, selective fit in their respective bores. And while they can wear or otherwise fail internally, I don't think that's the cause of your problem.

Start by checking at what pressure the relief valve opens.

Tx Jim · Jul 25, 2015

I agree with Bob that you need to check relief valve opening pressure.

jonwymillj · Jul 25, 2015

What is the best way to check the relief valve? As far as I can tell it is on the left side of the valve. Do I take the plug off the top and put a gauge on there? I put a gauge on the hose coming out (like to the loader) and the both went to about 1800psi.

tim s · Jul 25, 2015

Tighten the relief valve all the way in,, it's not needed in this system...

buickanddeere · Jul 25, 2015

Why would somebody hack up a JD tractor with a pto hydraulic pump? Deere tractors are noted for their high pressure/high flow hydraulics.
Connect it right with a T in the high pressure line and return the loader oil into a ported filter cover. Or use a power-beyond plate.
The loader joystick or control valves will need to be closed center.

Tx Jim · Jul 26, 2015

(quoted from post at 20:33:04 07/25/15) Tighten the relief valve all the way in,, it's not needed in this system...

Tim
I think you overlooked that a relief valve is required on this unit because it's being operated from an open center pto pump not closed center tractor pump. Although 1800 psi for relief valve seems low to me.

jonwymillj · Jul 27, 2015

It is a open center system. The valve is a Cross and I went to their website and found a drawing of it and they have three options, no relief, fixed, and adjustable. Mine is either the no relief or the fixed. I have to check it...
Has to (hacking it up) I use the hyd out the back for lots of other things and don't want to put the extra load of the loader on the system. I like the mid pump, tank, and valve that are all different system.

jonwymillj · Jul 27, 2015

The web address is http://www.crossmfg.com/parts/model-ba-three-spool
That is my valve. Mine is the no relief.

Tx Jim · Jul 28, 2015

Outlined in yellow you'll see that "no relief" for your FEL spool valve is for closed center not open center operation. Open center configuration should have adjustable or a non-adjustable relief valve but not "no relief valve". Is PBY port being utilized on this system??

jonwymillj · Jul 28, 2015

Sorry Tx Jim I was wrong about the no relief

I took it out it looked okay to me. But that is the only one I have ever taken out before! I don't know if there is a way to test it? Would putting a gauge on the left side of the valve do anything for me? You cannot see the plug I could take out on the drawing.
I do not have anything from the power beyond.
I think my relief is the 1500 to 3000.? Checking on that tomorrow hopefully.

Tx Jim · Jul 29, 2015

You can tee a gauge into the fitting where hose attaches to cylinder then when cylinder reaches it's limit of travel gauge should reflect relief valve setting

'

jonwymillj · Jul 31, 2015

Tx Jim will try to put a gauge on next week. I am running 303 oil is the oil too thin? Should I change to 406 or whatever?
Thanks

Tx Jim · Aug 1, 2015

303 is the older spec hydd oil which is fine for a 4020. Much later model tractors need hyd oil that meets J20C spec's.

Loader Question 4020

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