26x 1981 D5B Special Apllication tractor hydraulic question

Hello All,

I have a question on the hydraulic system on my tractor. I am relatively new to this machine, and I am hooking it up to a large pull behind Soil Ripper for amending some of my pastures. The action of the hydraulics are not working on the hydraulic ram. My educated guess is that the return valve is not opening to let the fluid return to the reservoir. However, on smaller rams it works perfectly. Is is the flow rate on these older pumps too slow? Our 1985 John Deere 2750 lifts the ram up and down perfectly. Any help appreciated.

Edit* I don't know how much variation there were in these machines, but according to the manual I believe the 3 sets of valves have a resting position, a float position, and a full position--they were built pretty specific for plowing wheat in the midwest, and I'm not sure what might have been different.

That's right - up/down/float on at least one of the three valves. The D8LSA has float on the first valve only. Sounds like a weird symptom that it works ok on a small ram but not on a large ram. Need to identify the differences between the JD and the Cat. One thing you could do is connect a line direct from the up port to the down port and see if it works ok. Do you know if any work has ever been done on the valves? Could be that it hasn't been reassembled correctly. Is the behavior the same across all three valves?

as other tractor hydraulic systems , I guess, with higher pressure hydraulic systems, can operate the ram, there maybe a non-return valve on the ram that requires more pressure than the D5B system can generate to open it.

I stand to be corrected.

Eddie B.