Hello to all I have a 1995 john deere 648E grapple skidder which has a problem with rotating the grapple, i can spin it fine to the right but will not spin to the left, so I reversed the hydraulic lines and then it'll spin good to the left and not right which to me indicates the rotator motor is fine, what else can it be ?? John deere does not sell parts or sections for the particular body valve anymore. I also reversed the check valves that are located on that particular control on the body valve or valve bank (to rotate grapple) and it still won't turn to the left... There are two pressure relief valves on the hydraulic motor also and i reversed those also with no luck. Any ideas to whats causing this would be greatly appreciated...
did the E series have the electric rotator switch in the handle or are they like the D series?
Maybe,that hose is separating inside and pressure causing inner lining to close off flow. Another hose cheap easy and quick check.
Theres no electric switch on mine, theres three handles one for the blade/dozer, the second one for the boom and arch and the last one closest to the rear window is for the grapple rotation and the grapple tongs.
There should be a cross over relief for the grapple rotate motor one the reliefs will likely be bad or have the orings blown off. The cross over valve are usually bolted to the rotate motor .
I assume you've made sure the linkage is moving the spool correctly? In between those check valves you swapped is a piston, maybe a counterbalance type of thing, you may want to see if it's stuck or off center somehow. I don't see any springs listed there, but I would think there would be.
Sorry I missed that you had already addressed the cross over reliefs.
as far as this morning we believe that is a faulty spool in the valve bank so thats my next job, John Deere doesn't sell these types of spools anymore so I had to find one from a parts dealer which does not sell spools by individually so I had to buy the whole valve bank /body valve. so Ill have 4 spare spools after this is done.
Do you have seperate relief valves in the spool for each direction. Just yesterday I had one stick open on a log loader. It would move only in one direction. Had a tiny piece of rubber in it holding it open in bypass. Checking pressure hoses between pump and spool now for internal peeling.
When I opened up the spool in question the valve came out with no hesitation and the oil was clear and clean but I did find that one relief valve was damaged and the spring that pushes the ball bearing back into its seat would get compressed and get stuck, i got it kind of filed down to where it wouldn't stick anymore and this didn't help anything, even when i switched these pressure relief valves the grapple would only spin in one direction.
Are you talking about the spool in between the two check valves? Or the actual valve spool?
sorry i should've been more clear, the spool between the two check valves, the valve spool moved freely also.
Okay, thanks. But then, where is the problem if everything looks okay and moves freely? Just for giggles, if you haven't torn the valve off completely by now, have you tried swapping the two hoses at the valve block? As Blk Prince alluded to earlier, you may just have a hose that's collapsed inside, it's weird they will sometimes allow flow in one direction, but like a flapper valve the pressure pushes the rubber into a sealed state going the other way. Also, in the work ports under the hose adapters, they show an orifice in each port, would be worth looking at, but you would think it would affect both directions if one was blocked?
Im going to get a pressure gauge and some fittings and check the pressures at the fitting for the rotate motor and coming out of the spool designated for the rotate this will tell me if the hose is blocked, Ill only be doing this on monday,
Good idea
Well I found the problem with the grapple not wanting to rotate, There was no pressure coming out of the valve bank in the bottom hose so I was getting set up to change the whole thing and i started to take off the hoses and connectors i guess i can call the (the fitting that the hose bolts too on the valve bank) and found a little plate inside with a very small hole in I guess its to limit the amount of oil flow for the particular function, anyway, there was a small piece if spring blocking that small hole stopping the flow of oil completely. so I flushed the valve bank and reassembled everything and now its good to go. I changed the two check valves also as i found there was a damaged spring in one of them.
Well I found the problem with the grapple not wanting to rotate, There was no pressure coming out of the valve bank in the bottom hose so I was getting set up to change the whole thing and i started to take off the hoses and connectors i guess i can call the (the fitting that the hose bolts too on the valve bank) and found a little plate (orifice) inside with a very small hole in I guess its to limit the amount of oil flow for the particular function, anyway, there was a small piece if spring blocking that small hole stopping the flow of oil completely. so I flushed the valve bank and reassembled everything and now its good to go. I changed the two check valves also as i found there was a damaged spring in one of them.
Great. Thanks for the update.