S-650-G HYDRAULIC SYSTEM

[deputy175]

I RECENTLY HAD MY HYDRAILIC PUMP OFF, AND SENT IT TO GET REBUILT. AS IT CAME BACK, THEY PUT A NEW FRONT SEAL ON IT, AND TOLD ME IT WAS IN GOOD WORKING CONDITION. I HOOKED IT BACK UP , FILLED THE RESERVIOR, AND STILL NO LIFT. I HAVE CHECKED THE FILTER, WHICH LOOKS BRAND NEW. I AM SLOWLY RUNNING OUT OF THINGS TO CHECK. ANY SUGGESTIONS.

IS THERE A RELEIF VALVE ON A 650 THAT COULD BE STUCK?

ALSO, AS IN MY EARLIER POST, THE DIAL UNDER THE SEAT SEEMS TO SPIN "A LITTLE TOO FREELY", COULD THIS BE THE PROBLEM???????? ANY INFO WOULD HELP.

 

[Villengineer]

I went back and read your previous post and noticed that you have power steering. That actually might help pinpoint the problem.
First, does power steering work?
If it doesn't work, then I would take the pressure line loose from the valve and take the coil wire off. Crank the starter real quick and see if you are moving oil. If you're not spitting oil out, either the line from the reservior to the pump is plugged and the pump is running dry (not good) or the pressure line is plugged. If you are getting oil out of the pressure line from the pump, then we need to check to see if the ps valve is the problem and that why you don't have ps or lift. It's entirely possible it's plugged with the old seal fragments. I don't remember if that valve has relief in it or not, if it does that could also be plugged open or broken and you simply can't build pressure b/c you're dumping the oil back to the tank side of the circuit.
If your ps is working take the pressure line from the ps valve to lift valve bank off at the lift valve and do the same procedure to check to see if you are getting oil through the divider valve and pressure line. If you aren't getting oil you now know the either the line is plugged or the ps valve is the problem. So take the line loose at the valve and try again. Oil = plugged line, No oil = valve problem.
So at this point we've probably either found the problem or know it's in the lift circuit itself. The only other possibility is if there is a relief in the ps valve that's working incorrectly and is closed at low pressure, but opens too quickly under load. The circuit gets a little more difficult now because so much is done internal and I don't have my manuals with the circuit here at work to walk you through a way to check it. If you do the above and still haven't found the problem, post and I'll try to figure out a way to trouble shoot the rest of the circuit. Hope this helps.

 

[deputy175]

Thanks for the reply. I have fluid to the hyd pump. I have fluid at the outlet side of the pump. I have no power steering. I think it must be something in the power steering pump. I think the tractor sset for a long while , and had little upkeep. I will tear into the power steering pump tommorrow am after I get home from work. I will let you know what I find. Thanks for the help...Ken

 

[deputy175]

I FIXED THE PROBLEM. THERE WAS AIR IN THE LINE. I TOOK OFF THE LINE AT THE RIGHT REAR OF THE TRACTOR AND AFTER PUSHING OUT ALL OF THE AIR [AND QUITE A BIT OF FLUID] IT BEGAN TO WORK. THANKS TO ALL WHO POSTED