4520 JD Hydro issue

[Feedinggrounds]

Hi I work at a golf course in northern mi. Have just aquired a used 4520 about 2004 vintage aprox 600 hours my issue is my lower links at the rear will not lift under a load they do work with no load. You can hear engine change and they try to lift about a inch, draft knob has been turned to both extremes. Machine is set up for loader but I do not have it. Fluid looks brand new,I think it is. The hydro filter is dated 40hrs 2005 yr. painted on. Any insight to my problem would help Thanks. Dan

 

[jenkinsph]

Have you tried the hitch with a light implement load? I would wan't to know if it is functioning correctly thru the full range of motion first. If it does work but has problems lifting a heavy load I would suspect the rockshaft cylinder needs rebuilding. I would change hydraulic filter based on the age and so you know it is good but that may not be the problem you are having.

The draft know you are referring to is the ROD (rate of drop) which is used to control how fast an implement lowers to the ground. It shouldn't affect the raising of an implement though. For testing purposes while trouble shooting your problem set it to the middle position.

To be clear you want to determine that the position control and valve is all working correctly and is in proper adjustment, with the hitch raising and lowering and stopping where you position the rockshaft lever. If that all works out and you still have a problem lifting a typical 800 lb implement then the likely cause is a worn rockshaft cylinder which can be rebuilt.

I would also wan't to verify the hydraulic pressures on an outlet are up to specs too, on my 4520 that is about 2500 psi iirc.

 

[Feedinggrounds]

Have new filter on it's way. My 4330 Kubota lifts at idle I did get the 4520 to lift at half throttle or more it is a heavy implement a Toro aerifyer for fairways. If that is normal then thats ok. My next issue is that the JD geometry at the rear is different than my Kubota, needing a shorter pto shaft. Was wanting to interchange implements between tractors but starting to be more trouble than its worth. The JD seems a lot more suited to farm type use, the Kubota is more golf course friendly turf wise, Just my opinion.

 

[Tx Jim]

My next issue is that the JD geometry at the rear is different than my Kubota, needing a shorter pto shaft.

Determining if the geometry on 3 pt & pto is different between tractors is simple. Just measure the distance from end of pto to a line in the center of draft links and compare the measurement for both tractors. After new hyd filter arrives & installed if 3 pt doesn't operate properly I'd recommend checking hyd pressure with a gauge.

 

[arlen4720]

Don't forget to clean the suction screen when you change the fluid and filter. The 4520 should lift just fine at idle. I lift my MX6 which is over 1000lbs at idle with no problem

 

[greasemonkeyok]

It is my experience that the 4*20 series needs rpm to operate the hydraulics. Mine does not do well at lower rpm.

Maybe I need to clean the suction screen because I can't lift the MX6 at idle.

 

[Furu]

My 4720 lifts fine at idle even with my 2000 lb chipper on it. Lift is slower but lifts fine. With your tractor do you have a PB on it? The earlier model 4x20 had an in line filter on the PB circuit. The three point lift is downstream of the PB circuit and if that filter is restricted it might be your problem. JD service seems to not know of this filter in their service manual. The only place it seems to be mentioned is in the PB installation manual. If you have PB I would definitely replace the filter.

 

[BigMike50]

It is my experience that the 4*20 series needs rpm to operate the hydraulics. Mine does not do well at lower rpm.

Maybe I need to clean the suction screen because I can't lift the MX6 at idle.

true for the loader but not so much for the 3pt. Should be able to lift full capacity of over a ton at idle. I say this because my smaller machine does

 

[Feedinggrounds]

Well lots to absorb, I did increase rpm and it did lift the implement but I do have a MX7 bushhog that will be used on this tractor. Will check screen when changing filter and go from there. thanks, Dan

 

[AKfish]

Well lots to absorb, I did increase rpm and it did lift the implement but I do have a MX7 bushhog that will be used on this tractor. Will check screen when changing filter and go from there. thanks, Dan

IIRC - Deere recommends that both the hydraulic oil be drained/changed and the sump filter cleaned @ 400 hours. If the charge filter (canister) hasn't been changed since 2005 @ 40 hours - I'd have to assume that most of the other routine maintenance hasn't been kept up with, either.

Tractor should get a thorough going over before hitting the "greens" - IMO.

AKfish