I have a 70's John Deere 300 Industrial tractor/loader (similar to a 1020) with a JD9250 backhoe attachment which has served me well for 15 years of occasional use. Recently, it has developed a hydraulic problem. First, after using it for hours, suddenly the loader and backhoe would not operate at all. Engine runs fine, transmission fine, tractor moves fine. No funny noises, just nothing. After about 10 minutes, hydraulic function came back, then came and went intermittently.
The next day, tractor ran fine for about 30 minutes, then the same intermittent loss of hydraulics. Next day, same thing. Oil level is fine.
I thought it might be clogged filters, so I changed both hydraulic filters (the transmission one and the loader return one. I also changed the hyd. fluid. The oil fluid and filters were clean as new. So I started it up, let it idle to self-purge for about 20 minutes, and it operated fine for about 5 minutes then, intermittently began to lose hydraulics, with occasional shuddering and air banging around in the lines. No amount to extending/retracting of the cylinders would clear them out. I have changed fluids on this tractor before and never had this problem. It feels like air is being sucked into the lines somewhere, but hoses and lines look tight.
I am not very familiar with hydraulics and would be grateful for a point in the right direction to troubleshoot this problem.
Many thanks,
Richard
The next day, tractor ran fine for about 30 minutes, then the same intermittent loss of hydraulics. Next day, same thing. Oil level is fine.
I thought it might be clogged filters, so I changed both hydraulic filters (the transmission one and the loader return one. I also changed the hyd. fluid. The oil fluid and filters were clean as new. So I started it up, let it idle to self-purge for about 20 minutes, and it operated fine for about 5 minutes then, intermittently began to lose hydraulics, with occasional shuddering and air banging around in the lines. No amount to extending/retracting of the cylinders would clear them out. I have changed fluids on this tractor before and never had this problem. It feels like air is being sucked into the lines somewhere, but hoses and lines look tight.
I am not very familiar with hydraulics and would be grateful for a point in the right direction to troubleshoot this problem.
Many thanks,
Richard