Hydrolics

[MH8675309]

I don't know about your particular machine, but most tractors use the transmission/differential housing as a hydraulic reservoir, and on those machines there is almost always a screen on the suction line to the pump. If you are operating in a dirty environment, or the machine is older, or fluids are allowed to become contaminated, that screen can become plugged so that the hydraulic pump cannot provide enough suction to start picking up the fluid. Your jerky movement in the hydraulic system could have been caused by a dirty filter, low fluid level, or this screen being plugged. I would have done the same thing you did and change the filter only after checking the fluid level and if that did not fix the jerkiness, I would have pulled the screen out of the transmission housing to make sure it was not plugged. If that did not fix the issue, check the suction hose/s and connections for a possible leak of air into the system. When all of these possibilities are not the problem, the pump is probably shot, or as somebody mentioned, the pressure relief may be stuck or failed.

Good post - I recently had the same issue and it was the pickup screen. All the oil had to be drained out - get at least 4 clean plastic 3 gallon pails - or more depending on how much it holds - to catch this. My screen was covered and I mean covered in what looked like wood shavings from a chain saw. Carefully scraped it off with a chisel and then sprayed it thoroughly with brake clean and then blew it out with an air hose. Put it back in filled it back up with the same fluid and working normally again. An easy fix. Start with the simple / cheap stuff first

 

[JRH02]

"... enviroment we are living in today."

Bwahh-hahhh.

Anyway, I have never found a polite way of saying "If you have to ask this question then you will not understand the answer." But we all had to start somewhere, didn't we? The danger is that some don't have the knack for some things mechanical, electrical or both. Is it just the hope that the red button next to the thingy needs to be pressed three times very quickly? And don't try to explain why.

 

[dfkrug]

... there is almost always a screen on the suction line to the pump. If you are operating in a dirty environment, or the machine is older, or fluids are allowed to become contaminated, that screen can become plugged so that the hydraulic pump cannot provide enough suction to start picking up the fluid.

Yes!

Some of those early Kubotas have only suction filtration, and water contamination can turn the oil into a booger-like substance. Priming the pump thru a clogged inlet screen may be difficult.

Photo is inlet screen from a mid-80s B8200. Ugh.