pilot lock wont release

[bandaidmd]

I added a double pilot operated lock valve to mt tilt to correct a leaky valve and all was good the first couple times i used it. I dont think I was having any drift at all so i let the box blade hang in the air with a jackstand under the left 3ph arm with a cable tie to mark the cyl, got maybe a 1/8" of movement but one of the fittings has a slight leak that i didn't notice so thats prob where the little bit of movement came from.
Started it up today and the tilt wont move? pilot valve will click in both directions and that one little pesky leak on the cyl side of the pilot valve will drip under load so its sending out pressure to at least that port.

Metro Machine Lock Valve-4 Port, Model# 408-04 | Machine Selector Valves| Northern Tool + Equipment

 

[J_J]

The pilot pressure has to overcome the pressure on the other side of the check for things to work.

You might have to jack up the attachment to relieve the pressure.

Excerpt:

This valve will lock a cylinder in place when a directional control valve is in the neutral position. In operation oil is directed to one of the valve ports and oil can free flow to the corresponding cylinder port. The pressure on this valve port will shift the pilot spool opening the opposite check valve. This will allow oil to return through the opposite check valve. This valve has a hardened steel seat and steel ball and therefore should not be used in applications requiring absolutely zero leakage. When using a pilot operated check to lower a heavy load the valve may chatter. An orifice in the line in some cases may be beneficial.

I see that you are using QD's, so reset all the QD's.

 

[bandaidmd]

I unhooked the QD's and it seemed they were fully coupled and holding pressure now I'm hoping some pressure will bleed off to recouple them. I cycled the control valve after shutting off the tractor but i'm not sure that relives the pressure on the QD's hooked to the lock valve. Tomorrow i may try jacking it up or the "hammer and punch" method to relieve the pressure.

 

[bandaidmd]

Update, After sitting all night I pushed in the poppets on the QD's coming from the cyl this morning one had no pressure and the other had just a little bit. Hooked them back up and it works again so rather it was the sitting overnight or the slight bit of pressure something must have had the pilot valve screwed up.