John Deere 521 loader drops before lifting

Mike M · Jul 24, 2011

John Deere 521 loader on a 5105 tractor. With a load in the bucket,or hanging from it,if you try and lift slowly it will drop first. I suspect some kinda lift check problem. I looked at the parts breakdown on these and they appear to not be adjustable. Jdparts shows like these were subbed several times. So does anyone know for sure if the newer ones are better ? or is there a service bulletin on this ? and if you pull them out do you loose just a little oil or does it keep running out ?

Thanks in advance.

David G · Jul 24, 2011

I had the same issue with my westendorf loader. The problem was in the float section of the control valve. I used an external control valve for the loader run off the remotes.

Craig C · Jul 24, 2011

What you are describing sounds like a pressure flow comensated system not adjusted correctly. All of our Deere tractors use the closed center system, but I have a Case IH with the PFC system and had to school myself on that in the past. You have stand by pressure and the valve sends a signal through the pilot line and signals the variable output pump to go to high pressure. Thing is that it should do it faster than you even notice. It will act a little different if you just crack the joystick at very low rpm. It is a fuel and power saving system holding 600psi instead of 2350 like the closed center.

Mike M · Jul 24, 2011

The 5105 is not a closed center system. Deere used to tout them as the "greatest" but now most of their tractors don't have it. Go figure ?

Heat Houser · Jul 24, 2011

Another possibility is a leaking piston packing.
What can happen is the the pressures equalize on both sides of the piston and the area of the rod becomes your "effective" piston. When you move the valve, pressures become "normal" and it sags down slightly. Another possibility is the load check is stuck open. Most loader valves have a check valve that will not allow oil trapped in the cylinder to vent backwards into the pump. The load check will hold the boom in position until the pump can pick up the load.

Tx Jim · Jul 25, 2011

(quoted from post at 14:52:21 07/24/11) The 5105 is not a closed center system. Deere used to tout them as the "greatest" but now most of their tractors don't have it. Go figure ?

Mike
I agree. I remember going to JD sales meetings and the speakers bragged on how great closed center was and how terrible open center was. Stressed all the fuel one could save when no oil was being pumped.

What type of hyd controls operate loader tractor or ind valve?

Tx Jim · Jul 25, 2011

(quoted from post at 19:39:07 07/24/11) Another possibility is a leaking piston packing.
What can happen is the the pressures equalize on both sides of the piston and the area of the rod becomes your "effective" piston. When you move the valve, pressures become "normal" and it sags down slightly. The load check will hold the boom in position until the pump can pick up the load.

Heat Houser
I'm not understanding your statement. Could you please elaborate? If the packing in a 2 way cylinder is leaking the boom would be continually wanting to lower if in raised position. I think the oil would just be moving from one side of the piston to the other side thus allowing boom to lower.

Mike M · Jul 25, 2011

It has a seperate mid mounted control valve with a joystick control.

Tx Jim · Jul 25, 2011

(quoted from post at 10:11:17 07/25/11) It has a seperate mid mounted control valve with a joystick control.

Mike
Have you pulled the check valves out of the JS valves to see if they're seating properly? Does your JS valves have the regenerative valve? Will boom settle if left off the ground/floor for a short period?

Mike M · Jul 25, 2011

I have not pulled anything apart yet.

I was hopeing to hear from someone who has had this exact thing or able to see if Deere had any service bulletins on it. I don't know if it is adjustable ? No shims or adjustment screw show in the parts book,but it does show it subbed a few times so they must of done some changes for a reason,maybe this reason.

Tx Jim · Jul 25, 2011

(quoted from post at 16:24:53 07/25/11) I don't know if it is adjustable ? No shims or adjustment screw show in the parts book,but it does show it subbed a few times so they must of done some changes for a reason,maybe this reason.

Mike
I edited my previous post as I meant seated not setting of check valves.

Could you please post the part #s of the substituted part numbers??

Mike M · Jul 26, 2011

RE222161

sub for RE73108

sub for RE210419

Tx Jim · Jul 26, 2011

(quoted from post at 13:06:27 07/26/11) RE222161

sub for RE73108

sub for RE210419

Mike
That's the same check valve that I asked you if you had removed it to check to see if it was seating properly. I agree that's several sub #s for a tractor no older than a 5105. Has D-TAC ever been contacted???

John Deere 521 loader drops before lifting

Mike M

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