Jerky/studdering Loader Movement

improviseadaptovercome · Jan 19, 2022

Since I bought my 1985 Kubota 5850DT, the loader movements have been jerky/studdery after reaching a certain point in their movement--usually about 1/4 of the range. If I reverse the movement and then extend it further, it goes a bit farther before jerking again. If I leave the valve open, the movement will eventually go all the way, but it takes a long time and the movement is slow and certainly not smooth.

I recently changed the hydraulic fluid and filters and everything looked fine. I checked the fluid level and it is a little over-filled.

I noticed when I shut the tractor down that when I relieve pressure in the loader valves, I hear a hissing/sloshing sound coming from the hydraulic fluid reservoir behind the cab (circled in the attached picture).

It has been suggested that my fluid is too low (despite being over full on the dipstick).

It has also been suggested that I remove the relief nut (big nut with a hold in it on top of the reservoir) and then test loader function. This makes the most sense to me so far, but wanted to see what you all think.

Any and all suggestions/thoughts are appreciated!!!

seville009 · Jan 20, 2022

If it's always done this as you say, I assume that you bought it used. If you don't see any fluid leaks in any of the loader cylinders, and if the cylinders are nice and smooth (no pitting), if it were me, I would disconnect all of the loader lines (lower it first, obviously), and then unscrew the lift cylinder lines and drain the actual lines. If the lines are old and cracking, maybe a tiny piece of debris is floating around one of the lines.

then reconnect everything, run the loader to purge any air, and top off the fluid.

hopefully that will work.

if the lines are drying and cracking from age, could also just put new ones on.

improviseadaptovercome · Jan 20, 2022

seville009 said:
If it's always done this as you say, I assume that you bought it used. If you don't see any fluid leaks in any of the loader cylinders, and if the cylinders are nice and smooth (no pitting), if it were me, I would disconnect all of the loader lines (lower it first, obviously), and then unscrew the lift cylinder lines and drain the actual lines. If the lines are old and cracking, maybe a tiny piece of debris is floating around one of the lines.

then reconnect everything, run the loader to purge any air, and top off the fluid.

hopefully that will work.

if the lines are drying and cracking from age, could also just put new ones on.

great idea. thanks!

yes i bought it used and it has been great so far.