loader on tractor sinking down

[zp18]

hello i have a quick question. i have a john deere 4200 with a 420 loader. every once in a while when i start it up and go to raise the loader. i have like little to no hydraulic pressure. i can raise the loader arms but as soon as i release the hydraulic control lever, the loader arms sink bank down. its not leaking oil anywhere.. all the hydraulic lines are in good shape and it has oil in it. i dont know what causes this or if i could be slowly wrecking the pump by trying to force the loader to work. let me know whats yous think. thanks!

 

[AchingBack]

hello i have a quick question. i have a john deere 4200 with a 420 loader. every once in a while when i start it up and go to raise the loader. i have like little to no hydraulic pressure. i can raise the loader arms but as soon as i release the hydraulic control lever, the loader arms sink bank down. its not leaking oil anywhere.. all the hydraulic lines are in good shape and it has oil in it. i dont know what causes this or if i could be slowly wrecking the pump by trying to force the loader to work. let me know whats yous think. thanks!

You've come to the right place, and a qualified expert will soon be giving better answers than I can. Based upon what I have gleaned from TBN, you possibly have air in the lines leading to the lift arms. I don't know the proper way to bleed the air from the lines. Best of luck on a quick, cheap fix.

 

[zp18]

that would make sense. because it only does it sometimes. last night i shut it off with the bucket curled under to let snow & water run off of it, and today i go out to plow a little bit and the arms kept sinking down. i parked it and let it idle to go inside and get something, and when i came back out the bucket was setting on the ground already.

 

[DT86]

It leaks down but not all the time?

 

[J_J]

Cycle the loader through about 10 times,and hold the lever at the end of the stroke for a few seconds to purge any air in the hyd system.

You might have some worn seals in the cyl.

Your valve spools in the valve might be worn.

The load check valve might have some debris in it. Remove, inspect and clean.

 

[zp18]

it worked fine today. didnt sink down at all. it only does it every once in a great while.

 

[Utopia Texas]

You say the tractor has fluid in it but is it at the correct level?

 

[murphy1244]

Raise loader and disconnect lines if it leaks down its the cylinders IMO.

 

[zp18]

yes it has enough hydraulic oil. it doesnt leak out anywhere.. all the lines are like bran new. and ok, ill have to try that

 

[J_J]

Do not raise the loader and disconnect the lines. It could drop on you.

With the loader lowered. remove the base line and retract.

If fluid keeps flowing, the seals are bad.

 

[zp18]

what do you mean by 'base line' ? just wonderin

 

[J_J]

Opposite the rod end.

 

[zp18]

oh ok man.

 

[wdchyd]

Like jj said cylinders need a repack

 

[zp18]

alright

 

[oldnslo]

Does your directional control valve have cables to operate or is it all mechanical linkage? From what you are describing it sounds like the valve may not be centering properly all the time. This can be from moisture in the control linkage, moisture in the spring caps on the end of the valve spools etc. If the valve is not leaking and the cylinders are full of fluid the loader cannot leak down fully even with bad seals on the cylinders.

 

[zp18]

mechanical i would imagine. im just curious as to what would cause it to happen. it only happens every once in a great while. usually when i set the bucket curled under over night, like when the oil goes back 'into' the tractor it sucks air in the system