# 4020 John Deere hydraulics



## notmydaytoday (Sep 16, 2016)

The hydraulics bleed off when you raise the lower up it will slowly lower it's self when you let off the controls. The loader will only pick up the front of the tractor rolling the bucket it does have the power to do it with the arms.

Also when you open the gate on round baler it slowly closes to.

I checked the fluid level is good and no signs of water.

So is the pump getting weak or am I missing something like a plugged screen somewhere.

This tractor is new to me. Loader is hooked to rear couplers.


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## Tx Jim (Jun 30, 2014)

There are several things that can cause the closed center hyd system on your tractor to be slow. Yes the trans oil sump screen could be clogged. It can be inspected/cleaned by removing a plug on LH side behind hyd filter & in front of rear axle housing. One needs to drain hyd oil or insert nozzle of an operating shop vacuum in hyd filler hole to create a vacuum so oil won't run out when plug is removed. If you don't know how long it's been I'll suggest to change hyd filter(part # AR75603 $10.64). I'll also suggest to check hyd stand-by pressure by plugging a 5000# gauge in rear breakaway then move control lever to activate the gauge. Factory pressure was 2250 psi but can be set to 2350 psi with no harm to system. A large internal hyd leak can cause hyd functions to operate slow because it robs from pump output. If trans is in park or brakes are being applied while attempting to raise frt tires with FEL then it will make loader have to work harder because rear tires need to roll forward a little while frt tires are being raised.


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## Ranger518 (Aug 6, 2016)

Do you have the clutch pushed in when this is happening?


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## Farmineer95 (Aug 11, 2014)

Power shift or synchro trans?


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## Farmerbrown2 (Sep 25, 2018)

Need more info is it a side counsel or and older one with dash controls. Does it do the same thing with an implement.


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## Tx Jim (Jun 30, 2014)

I agree trans type is very important to how hyd's operate. If OP's 4020 has powershift trans then depressing clutch pedal should not affect hyd operation because PS trans pump operates 100% of the time engine is running unlike Syncro-range trans where trans pump stops pumping when clutch pedal is depressed.


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## Tx Jim (Jun 30, 2014)

Farmerbrown2 said:


> Need more info is it a side counsel or and older one with dash controls. Does it do the same thing with an implement.


I'm curious how yr model of 4020 will affect hyd operation as both early & late model 4020's have similar hyd systems.


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## Farmerbrown2 (Sep 25, 2018)

Tx Jim said:


> I'm curious how yr model of 4020 will affect hyd operation as both early & late model 4020's have similar hyd systems.


 I agree they are similar systems but earlier 4020's control valves are under the hood above the motor where as later ones have everything behind the seat .


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## notmydaytoday (Sep 16, 2016)

Sorry it has taken so long.

Clutch is not pushed.

Controls on the dash.

It is a 1967 model. With syncro-trans.

The gate on my baler slowly closes the same as the loader lowers.


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## Tx Jim (Jun 30, 2014)

The valves(key 26 & 27) in control valve housing need adjusted or replaced/adjusted. The valves are tricky to adjust & normally require a technician with prior adjusting experience to adjust them. You could try switching hoses on each breakaway coupler to see if baler tailgate will remain closed but switching hoses will cause control handle of valve to be moved in opposite direction to control baler gate.


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## Ranger518 (Aug 6, 2016)

You may also like at the stroke control valve or the priority valve could also be stuck causing a issue.


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## Tx Jim (Jun 30, 2014)

Ranger518 said:


> You may also like at the stroke control valve or the priority valve could also be stuck causing a issue.


Stroke control or priority valve will not cause scv to bleed off. Yes valves you mentioned could cause loader to not lift tractor frt tires up if tractor is in neutral.


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## Ranger518 (Aug 6, 2016)

Tx Jim said:


> Syr
> 
> Stroke control or priority valve will not cause scv to bleed off. Yes valves you mentioned could cause loader to not lift tractor frt tires up if tractor is in neutral.


Yep I was thinking just weak hydraulics. So just curious do you thing part 26-27 are not seating it off causing it to leak down and also causing a high pressure leak which will be giving it weak hydraulic pressure?


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## Tx Jim (Jun 30, 2014)

Yes one or both valves(key 26 or 27) is leaking. I remember from when I served as a dealer service manager how much FUN the rockers(key 11) are to adjust. IMHO JD engineers made the scv & steering valves on 3020/4020's WAY TOO complicated. If 4020 was mine I'd install a 2 spool valve similar to control FEL to hyd control towed implements & disconnect the factory scv.


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## notmydaytoday (Sep 16, 2016)

So the valves on the tractor need attention form what I am getting.

I was hoping it was something I could fix myself.

TX Jim how hard is it to convert to the 2 spool valve you suggest.


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## Tx Jim (Jun 30, 2014)

Not really that difficult but one would need to make a bracket for valve to mount on or mount valve on RH fender plus routing hoses. If you decide to do that conversion you'll need a closed center plug with correct seals & I can post photos showing where to attach pressure & return hoses that connect to in/out on valve. The routing hoses won't be as neat as factory SCV but it would suffice. You could route hoses to original rear breakaway couplers. JD technician I'm acquainted with in Ohio charges $250 plus parts to renew 1 scv valve. A valve can be purchased for $161.15 + closed center plug,fittings & hoses


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## notmydaytoday (Sep 16, 2016)

Thanks for the help pictures would help. Going to talk to the dealership and see what they charge to rebuild the ones on tractor but if to costly I will do as suggested.


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## Tx Jim (Jun 30, 2014)

I hope your local dealer has a technician that has prior experience with adjusting those valves!

If you decide to utilize 2 spool valve you could mount spool valve on RH side up by firewall & connect hoses to existing hyd tubes that are connected to original control valve for a cleaner appearing conversion. The tubes I'm referring to go under floorboard to rear breakaway couplers.

Pressure connection for spool valve is 1st photo & return is 2nd. Or if you bypass original scv you could utilize those connections for spool valve


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## Farmerbrown2 (Sep 25, 2018)

Once again you have given very sound advice. I’m surprised no one has made a conversion kit for those control valves. PIA is what they are. I see some one is making a power steering conversion for the 20 series Deere tractors.


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## Tx Jim (Jun 30, 2014)

Farmerbrown2

Thank you. Is the power steering conversion the type that resembles hydrostatic valve in the late 30 series rowcrop tractors? If so that should be an improvement over the original complicated valve.

Jim


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## Farmerbrown2 (Sep 25, 2018)

The one I was looking at used the same as a 2-105 White . My understanding was the White’s where a closed center system. One of the tractor parts companies had them,maybe it was Abilene but I’m not sure.


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