Jerky Hydraulics

[allyoop]

Hey to all. New here. I have a John Deere 790 that I recently changed the hydraulic fluid and filter as well as cleaning the filter in the bottom of the drive axle. It was working fine when I last used it about 2 months ago. I just tried to use it and all the hydraulics are very slow and very jerky. Any help would be greatly appreciated!

 

[laurencen]

air in the system, check the level and figure how to get air out, if you run it for some time the oil gets tons of bubbles and it needs to sit for many hours to get them out

 

[allyoop]

air in the system, check the level and figure how to get air out, if you run it for some time the oil gets tons of bubbles and it needs to sit for many hours to get them out

I have run it working the hydraulics to remove any air. The reason for changing the fluids was because I had to rebuild a cylinder on the FEL. After the rebuild and fluid change, I operated the FEL until it operated smooth, then used the tractor several times with no problem. The problem arose after the tractor sat for a couple months.

 

[Harry in Ky]

Go over all the hose clamps on the hydraulic suction line. If possible use a 1/4" drive ratchet and socket. More effective than a screwdriver.

 

[allyoop]

Go over all the hose clamps on the hydraulic suction line. If possible use a 1/4" drive ratchet and socket. More effective than a screwdriver.

With laurencen and your answeres, I am assuming that you both think I have an air leak in the suction side somewhere. Would that be a safe assumption?

 

[Peter 315]

I think that's the assumption check all the hoses and the filter to make sure there all tight . Is the hyd oil full?

 

[allyoop]

I think that's the assumption check all the hoses and the filter to make sure there all tight . Is the hyd oil full?

Oil level is full. I'll run down the suction side and see what I can find. Thank you all!

 

[Peter 315]

See if the rubber hose is wet on the screen, might be cracked

 

[laurencen]

is the pump cavitating, is it possible you have to prime the pump?

 

[allyoop]

Ok. Ran down all the suction side and found the filter a little loose, 1/4 turn. Tightened it, found nothing else and still had the problem. Decided to check the filter screen in the bottom of the axle, (even though it was just cleaned about 10 running hours ago), and guess what? It was completely clogged. Cleaned it, problem solved. Thank you all for your input here. You got me looking and thinking right!