Newly installed grapple freezes up

[muttiwilson]

Every now and then while using the grapple that is running off my L3350 factory remotes, the cylinder will lock up. The FEL and 3PT arms work just fine, only the grapple. The tractor lugs and the hose running to the remotes from the loader valve (PB) pulses, but the cylinder doesn't move. Nursing the remote lever slowly one way or another will get the cylinder working again. Any ideas?

 

[k0ua]

Every now and then while using the grapple that is running off my L3350 factory remotes, the cylinder will lock up. The FEL and 3PT arms work just fine, only the grapple. The tractor lugs and the hose running to the remotes from the loader valve (PB) pulses, but the cylinder doesn't move. Nursing the remote lever slowly one way or another will get the cylinder working again. Any ideas?

To me it sounds like that cylinder has a problem. If you hear the pump lug down, and see the hoses pulse, then fluid must be getting out of the valve and down the hoses, and if the cylinder hangs up, then that is a cylinder problem it sounds like to me.

 

[CADplans]

I think the hoses to the valve (in and out from tractor) are reversed,,,,

 

[wdchyd]

Maybe mechanically bound?.......hinge bound or bent hyd rod?

Next time it happens might need to disconnect hoses and manually move the cyl

 

[TMGT]

Bad or not properly seated coupler or bad hose?
Just went through this with a hose on my BH thumb, working fine then would "lock" in place, turns out one of the hose fittings was crimped too much and collapsed, did it intermittently for a bit before not working at all.

 

[kennyd]

My guess is a coupler that is not seating 100% all the time.

 

[muttiwilson]

I'll check the rear couplings. That may be it. The hose running to the remotes pulses and there is an audible click under the seat area but I do not think the hose(s) running to the grapple pulse. I'll check that tonight and check back in.

 

[MinnesotaEric]

Every now and then while using the grapple that is running off my L3350 factory remotes, the cylinder will lock up. The FEL and 3PT arms work just fine, only the grapple. The tractor lugs and the hose running to the remotes from the loader valve (PB) pulses, but the cylinder doesn't move. Nursing the remote lever slowly one way or another will get the cylinder working again. Any ideas?

You have an open center valve and valve body that is installed between the power beyond port on your loader's valve and your three point.

When the grapple binds, confirm the three point lifts normally. This tells us that fluid is flowing through the open center valve and valve body (from pressure P to tank T) as it is supposed to.

If the three point will not move or moves slower than it should then there is a problem. Report your findings.

Most likely, you have a coupler that is not seated properly.

Turn off your machine. Cycle the loader joystick all over, and cycle the electric over hydraulic valve both ways to relieve pressure.

Disconnect your third function couplers. Bang the couplers' spring loaded detents on anything to relieve any residual pressure left in the grapple lines and then reconnect. Check performance and report findings.

 

[1stDeuce]

If it always happens with the cylinder fully extended, it could be that the cylinder is opening the jaw to the point that it has no leverage to close it... Or rather, all the pivots end up in a straight line, so that the cylinder is trying to compress them all instead of swinging the jaw... ?? I saw a writeup where the stops on the jaw on someone's grapple was to slightly over-center so it wouldn't close, and they were "banging" it down to force it back over-center so it would close... They added stops to keep it from opening quite so far and zero issues after.

If that sounds similar to your case, try not to open it all the way up.

Just another possibility...

Otherwise

 

[muttiwilson]

If it always happens with the cylinder fully extended, it could be that the cylinder is opening the jaw to the point that it has no leverage to close it... Or rather, all the pivots end up in a straight line, so that the cylinder is trying to compress them all instead of swinging the jaw... ?? I saw a writeup where the stops on the jaw on someone's grapple was to slightly over-center so it wouldn't close, and they were "banging" it down to force it back over-center so it would close... They added stops to keep it from opening quite so far and zero issues after.

If that sounds similar to your case, try not to open it all the way up.

Just another possibility...

Otherwise

It locks up in all spots of the stroke. I first thought it was going over center but that's not it. I'm going to replace the female connectors from the remote valve. I have no flexing of lines after the remote valve when it locks up. I don't think the remotes were ever used and it's 30 years old. It's worth a shot. I'll be going up to the property on Friday and will swap them out then.

3pt works just fine as do all of the other hydraulics.

I banged on them, released the pressure and reconnected with the same issues.