john deere 648d skidder

[bentvalve]

hi
having trouble with the valve bank that controls the grapple the rod that opens and closes the grapple does not go down far enough witch makes the grapple close very slow,tried removing the rod but will not come out,any idea how to remove this so i can see whats obstructing this. thanks mike

 

[Delmer]

You tried to remove the valve spool from the bore in the valve housing? Is there a cover on the bottom of that spool with two small bolts holding it on? and you removed that cover? and the spring underneath the cover? and the valve spool still won't come out of the housing? Then you have something inside of the valve blocking it, could try compressed air through one of the ports, like the circuit relief, but don't change the setting of the circuit relief. Could try wiggle and twist on the valve spool until it comes free.

Does it feel like metal on metal, or maybe something soft in there? if it's soft, you might risk pulling it out with force.

 

[bentvalve]

i tried pulling it out from the top that had a little plate with 2 screws,the bottom has an aluminum barrel is that what i have to take off and will it come out that way.when trying to pull it out from the top it only came out about half way then stopped.

 

[Delmer]

yes, the aluminum barrel sounds like the cover I was thinking of. According to jdparts, the cover has FOUR small bolts in the base that have to come out. I'm not familiar with ALL of the stuff in that diagram that is under that cover, so I'm not sure if the small bolt in the center top of that cover has to be removed or not, try it first without removing that bolt, if it doesn't come off, then the bolt must need to be removed. Be careful not to drop anything out of there, and keep it in order, it shouldn't fly out, but you never know if something is broken.

The valves I'm familiar with just have a spring that bolts to the end of the spool, it provides the centering spring action when you operate the valve either direction. Hopefully you find something obvious broken, apart or whatever. If that cover fills up with oil, that will keep it from going down also. Replace the seals on both ends while you're at it.

 

[bentvalve]

it was not easy getting those screws out,but i think i found out what happened,when i removed that bottom barrel everything fell out and found that center screw was unscrewed from the spool keeping the spool from going all the way down.i think the whole valve bank will have to be removed to replace tight quarters. thanks for the help mike

 

[Mike L]

What part of the state are you in?

 

[bentvalve]

lyman maine