Cat hydraulic pin grabber won't lock

I have a Cat 308e2 with hydraulic pin grabber. Today all of a sudden the back of the bucket would come loose. I tried locking and unlocking a bunch of times with no luck. I can move the wedge lock in and out with a pry bar. Any ideas on where to start looking? Serial # CAT3080308ECFJX01196

Cat hydraulic pin grabber won't lock