I realize this is an old post but i figured I would share my experience with this anyways as it happened recently to our TH514C

We have had this happen twice now. Once the eye on the end of the cylinder actually ripped apart and the other time thankfully the cylinder was put incorrectly and was able to slide off the bushing. In our application the operators are used to running a JLG and they always drive around with the attachment tilted up all the way. So if you have the boom up and the attachment tilted all the way up and you go to let the boom down the two compensation cylinder can't compensate and tilt the attachment up farther while you lower the boom. It seems there is no bypass valve or it doesn't work fast enough and over time you will end up with a catastrophic failure. We have mandated that the attachment whether it be forks or bucket etc should remain level as much as possible to allow for the compensation cylinders to do their job. I think the biggest issue is lifting and lowering the boom with your attachment tilted all the way up or down. Seems like a really bad design and I did talk to a CAT Engineer about it. However the machine now is too old for them to really care about it anymore. Hope this helps some more people with this problem