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
When you move it is the switch in the close position ? If so it may be bypassing in the piston itself
If yours works through the monitor panel I seem to remember there was a two step process for locking and unlocking those things. Check your operator manual.
If it's a red wedge like I'm thinking I have a customer that has 2 and it appears there is not enough force to lock when it gets dirt packed in there. I have to drive pin out and clean out before it goes out on rent. Hope I'm thinking of the same issue your having.
It is the type with a red wedge. When you curl the bucket all the way in it will put pressure on the wedge. But as soon as you release the joy stick you can move the wedge with a pry bar. I had the check valve out of the valve body on the coupler and it looked fine.
If I had to guess. There is probably fragments in the relay valve. We had the opposite happening on one of our 345’s and the cylinder for the locking jaw was coming apart on the inside
Capped the lines going to the cylinder and could not move the cylinder with a pry bar. So the cylinder and packing should be good. Must be a bad valve.
Was finally able to dig a little deeper and I'm 99.99% sure I found the problem. Damaged seals inside the lock cylinder. Any idea how this could happen? Not like this cylinder is going in and out all day long. Only 1300hrs on the machine. Called cat they only sell a kit for $370. I'm going to see if a hydraulic shop can get me the seals.
In my fleet, that occurs when doing everything but digging...including, but not limited to, compacting dirt by beating it in with the bucket heel, and shovel digging (putting the bucket on backwards). Both processes attempt to dislodge the bucket toward the cab, resulting in pressure spikes in the latch cylinder. If it's 1st gen Cat (Miller Bug), the cylinder barrel swells, or the jaw pivot pin shears. If it's a 2nd gen Cat (Centerlock), either the rocker arm saddles fracture, sending the cylinder and the cylinder's external tubing into the stick, effectively destroying the cylinder, or...the rocker arm anchor pins shear, resulting in a 3week delay awaiting new pins. If it's a 3rd gen Cat (sliding wedge), well, we haven't had the opportunity to endurance test one of those. Regardless, using a hydraulic coupler for any operation opposite of digging can and will result in failure of some component.
We had this somewhat happened on the 345bl last year. Multiple causes. Guy was pounding on concrete footing and the worn out cylinder. 20000 hrs who would have guessed. Lol
20000 hours? Hell, I'd have been happy with 2k hours on my 345c.
Thank you for your reply. I believe it's a 3rd gen cat. It has a red sliding wedge on the rear and a safety latch on the front pin.
We had borrowed a 305 from another company. Nice little machine, it had the cat quick attach. It had a safety latch that had to be moved manually, then the lock was opened with the touch screen. When you put the bucket back on, the safety latched it's self then the touch screen engaged the lock. The first time I tried our 308, I opened the safety then used the touch screen, all the indicators lit up. Bucket wouldn't come off. Tried again, and again and again. Called the mechanic, he was on site. Told him the problem. He got me to work the control while he watched. He walked up, reached in the front window and took the nice shiny cat wrench that was at my feet, manually opened the lock and said try it now. How dumb did I feel.