Knowledgeable 3rd function grapple owners

[jimbo913]

Hi,

Looking for someone familiar with factory Kubota L5030 or similar tractor with 3rd function valve and clamp bucket or grapple.
I can clamp and open but when button is released it doesnt hold. Is there a valve or switch to change system operation and hold pressure both directions?
I know some skid steers have a valve that gets moved to go from motorized equipment like augers to clamps, etc. which need to maintain line pressure.

Thanks

 

[firejunkie]

The only circuit that would hold pressure on the valve would be a locking circuit that locks the function(i.e a trigger on the handle to lock the button, or switch for use with an auger/breaker/mixer etc) on a skid steer. Your setup is probably similar to mine in which you have two momentary switches on the handle, one for flow forward, and one for flow reverse, each on activates the coil on either side of the valve to flow fluid in one direction or the other.releasing the button, puts the coil and hence the valve in a neutral state. Meaning no flow in either direction.
Now if your issue is when you operate lets say a grapple, and lets say you grab a log, and the grapple is losing its grip as you travel(or as soon as you release the button) you have a hold circuit problem. This can range from an easy to see external leak of fluid from a line o-ring etc, or it could be a cylinder leaking internally, if the cylinder has a hold valve built in,is it leaking? Or a cheap cylinder with poor internal seals, or is it the valve itself leaking internally through a stuck valve or o-ring, cracked valve body etc. Or it could be a bad coil,or switch still holding the circuit open even after the switch is released.

 

[jimbo913]

Hi,

Thanks for the reply. You provided some great information to help in trouble-shooting. I was not sure that the handle mounted rocker switch was holding pressure both directions when in nuetral position (not pressed). I was affraid that it was in nuetral and not holding pressure and there was some sort of switch or valve somewhere that switched it from locked to unlocke ld pressure.
I figured that it would need to freewheel for items like mixers, etc which cant stop on a dime.
I dont believe anything is damaged, so do you think air could be in the lines? If so, will air eventually work its way out or am I going to have to try and bleed it?

Thanks