Hydraulic problem

Working on my swather and the hydraulic are giving me fits. Everything worked good before I changed the drive belts. To change the belts I had to remove the pump from the drive to pass the belt through. I did not open the hydraulic anywhere, just pulled it off and layed it down. Now I have very low pressure, just enough to raise the header and real at full throttle, but I get nothing from the variable speed valve. As I said, everything worked good before. Here is a pic of the valves.




I pulled the lines near the pump and have oil flowing there. In the pic the pressure line is in the upper left, the rubber line you can just see. The u shaped line from the left to right valve is pressure to the second valve. The return is the right line on the left valve that is T'd from the right valve. The far left steel lines that are T'd are the header lift. The right rubber line in that valve is the variable speed line. The right valve is the real lift, the rubber line dropping down and left is that feed.

So where could the problem be? I don't know what the pressure is, I'll have to get a pipe fitting to hook up my Gage. It will lift the header and real at full throttle, but not at idle. I'm stumped since everything worked before.

Ask the last guy that worked on it! : )

Do you suppose when you layed it down you got an air pocket in it somewhere? Maybe if you bleed every line.

I don't know the machine, but let me ask this question. When you pulled the pump, is it possible you got the coupling back wrong, had a key go missing, etc? I've seen things like this happen where the pump is turned passively, but not with enough power to actually do anything.

Since pulling the pump seems to be the only thing you did that has ties to the hydraulic system, that's where I'd start looking.

How is the pump driven? Direct drive though a coupler of some sort, or belt drive? Where is the reservoir? Is there a low pressure type hose from the reservoir to the pump, which could have kinked, and now be drawing flat when under suction? Can you get someone to look at things as you try to operate them?

On the very simple, similar system on the old Gleaner E the belt had to be "fiddle string" tight or it would slip. You would check the belt and believe it to be tight enough. But have someone operate the controls while watching, and the you could see the pulley slowing down.

You can see the pump on the very bottom of this pic, it drives through a coupler on the end of the shaft with the big pulley. Thought maybe that belt was slipping so tightened it, it was not slipping.





The reservoir is part of the pump.

Jon I am with Bob and Wayne on this to get started. Is there any other valves or control you could have touched or moved. Next if possible start from resivior and work out. Good luck.

I wonder if a hose went bad inside once it may of been bent out of the way ?

OK, so it's definitely not a belt drive, nor supply hose problem. There's probably a screen down in the bottom of that sump. It would be worth checking.

If one of the spool valves is stuck a tiny bit off center, or not returning all the way, it can screw everything up.

I would try to tee in a pressure gauge if possible. You probably have a bit of gunk stuck in the relief valve. By moving the pump around it could have loosened some gunk that had settled in the reservoir or broke loose from inside of a hose. HTH Jf


P.S. Keep up the funnies I read them daily.