Overheating 520 Hydraulics

Gary Puckett · Jul 8, 2016

I purchased an 810 two bottom plow for my 520 about two miles from home. I have never used the hydraulics before, but did change the fluid with Deere hydraulic fluid recently. It is full. The lift seems to work right and lifted the plow easily. Coming home, the pump got really hot and started smoking. I stopped twice and let it cool. The remote cylinder lever was centered. What might the problem be? I have the tractor manual and plow manual and have read both.

BushogPapa · Jul 8, 2016

If the Hydraulic lever was Centered, the system was NOT putting any load on the Hydraulic pump..it was "Holding" the position via Check-valves..

Have you checked the PTO for proper oil level..?

Are you referring to the Hydraulic Pump on the Governor..?

Never heard of one of them "Smoking"...

Let us know more..!

Gary Puckett · Jul 8, 2016

Thanks. The rockshaft lever was in the up position obviously, but I was just stating that the other remote lever was centered meaning there was no pressure on the pump. It was the pump that was really hot. What effect would the PTO oil level on the have on the hydraulics? I did check the PTO and it was on, but isn't it independent from the hydraulics?

BushogPapa · Jul 8, 2016

Well, I have a Late Styled JD "B" and a 520...still don't remember if the 520 has a pump driven by the PTO ( at the rear)...I was thinking that if that was the source of the over-heating, it would be very uncommon...
After thinking about it, I guess the only Hydraulic pump on a 520 is attached to the governor...

Was the Hydraulics "Cycling" often, to keep the plow up..?? If so, the Hydraulic oil might get sort of how, but it should not smoke..!!

Cycling often usually means the Hydraulic piston ring is leaking a little or the Check Valve may be too..

I have always used engine oil in my hydraulics on all my older tractors, with no trouble what so ever...

MSM · Jul 9, 2016

The draft control is built into where the top link attaches to the tractor. Possibly it was trying to hold position as the plow bounced while you were roading it home and was constantly lifting the plow which would cause the pump to build pressure and get hot. Check your manuals and see which of the holes the top link should be in for the plow you have. IIRC there is a limiting plate with a set screw that is installed in one of the holes in the top link mount to keep the draft control from constantly making adjustments. I know the 3 bottom that came with my fathers 520 had this plate, it should be shown in the tractor or plow manual

fixerupper · Jul 9, 2016

It could be the famous idler gear that drives the pump.

machineryman · Jul 9, 2016

I agree with the post about the position locations. You seem to be putting a constant pressure on the pump and it's wonder it didn't destroy it. I suppose you didn't know that the pump has a turn knob to disengage it when not needed. That was the purpose of this feature so people wouldn't hook items up when the lift wasn't needed. "Also" John Deere made a position carrier for transport such as your's. Hopefully you haven't damaged the pump gears or body.

ET · Jul 9, 2016

If the linkage for the rockshaft control lever wasn't adjusted quit right the control valve never gets completely back the neutral when the plow is raised all the way so the pump keeps working. Did you try to let the plow down a little ways to see if anything changed.

buickanddeere · Jul 9, 2016

As fixer upper stated, few operator's are aware of the hydraulic pump disengagement function. The pump wears out and wastes fuel whirling away pushing oil through the system for thousands of hours while no hydraulic loads are being used.
Odds are it's time for the pressure lubed idler shaft update .
There ain't no transmission driven hydraulic pump on a first numbered , 20 series, 30 series , R or late AR.

Gary Puckett · Jul 9, 2016

In this case, the operator is aware and the pump is off when not in use.

buickanddeere · Jul 9, 2016

Been a lot of operators since 1957 or so.

Gary Puckett · Jul 9, 2016

Thanks. Can you tell me more about the transport carrier positon? Is that a mechanical device? The pump does stay off when not in use.

Gary Puckett · Jul 9, 2016

Good point.

r.w.b. · Jul 9, 2016

I was thinking piston seals also.they went bad on my 630 and got hot 1 day while carrying a load,and then it started hunting or bouncing.new piston seals was all it needed

fixerupper · Jul 9, 2016

Driving one mile would not take up enough time to overheat the pump. Does the relief squeal? If the pump is pushing oil against something that is deadheaded, like a three point that can't lift the load the relief will be very audibly squealing and the engine will be slightly laboring. I assume if the three point hitch valve is misadjusted so the pump is still trying to lift it after it has hit the top the relief will be squealing. A four bottom mounted plow hanging on a 630 won't come close to being heavy enough to squeal the hydraulics. A hog cart on the back of a 630 hauling five big old sows will make it squeal when it is only a foot off the ground and the front end will be very light. If oil is bypassing the lift cylinder the three point will be jerking and hunting. I still suspect the idler gear. That bugger WILL make smoke when the gear is galling the shaft.

Gary Puckett · Jul 10, 2016

fixerupper, thanks. I have heard some squealing and the lift does hunt some. Not having had one of these pumps apart, the area that got the
hottest was on the left side of the pump around a shaft about one inch in diameter that protudes through the casting. It scorched the paint
around that shaft. Is that shaft he idler gear shaft? Thanks

buickanddeere · Jul 10, 2016

http://jdpc.deere.com/jdpc/servlet/com.deere.u90490.partscatalog.view.servlets.HomePageServlet_Alt

fixerupper · Jul 10, 2016

Yes that is the shaft and it sounds like that is your problem. Don't use the pump and try not to run the tractor much until the shaft is fixed. The idler gear can weld itself to the shaft and spin the shaft. You don't want that to happen. Keep us updated.

fixerupper · Jul 10, 2016

Come to think of it, it's possible the squealing is the relief valve. A squealing relief means an over worked pump and the stress from tha pump working constantly finished off the idler. The squealing might just be the sound of the idler going bad and everything else is OK. I'm not there to listen to it.

buickanddeere · Jul 11, 2016

Best to just inspect and rebuild the pump then install the pressure fed idler anyways . Eliminate the potential problem once and for all.

John Deere D · Jul 11, 2016

My Neighbour, was noticing high oil temperature on his JD 520 when ever the 3 POINT HITCH was all the way UP. He was not aware that the HIGH PITCH sound was the relief valve relieving. When the lift control lever was moved downwards off the full lift position (1/16>1/8 " )the noise of the relief valve relieving and high oil temperature became a thing of the past:

Overheating 520 Hydraulics

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