Cat 299D2 XHP issue with Spool Valve?

[bso32177]

Grapple cylinders are extending with this issue, and when im clamped tight on material they wont stay tight so they lose their hold and will retract a bit. Cylinders are plumbed correctly. When i roll back on the thumbwheel they retract and when i roll forward they extend. Each Aux line at quick connect comes to a T and then go to the corresponding ends of the cylinders. Ive bypass tested the cylinders and they are not bypassing.

 

[Cmark]

Well if the cylinder drifts down rod-out AND won't hold pressure rod-out AND both cylinders are good then it looks like you have leakage on both lines. I would say the next step would be to remove the control valve and take a look inside the aux section.

 

[bso32177]

Where is the control valve located? Is that the section of the valve block where the two aux solenoids are? The one that midway up the firewall?

 

[Cmark]

Yes. It's the one Nige has been discussing with you. This is the cross section. Follow your auxiliary lines and they should go to ports A and B.

 

[bso32177]

I see. Ok. I will check in the morning and report back. Thank you.

 

[RodriguezGrading]

Hello all, came across this post when researching a similar issue with a 4 in 1 bucket. Won't hold in the hold position bucket closes as soon as you let off the roller but will hold open if you disconnect the male coupler on machine side. Did you happen to find a solution to your problem, my 299 is roughly same as yours model-wise. Any information would be helpful. Thank you.