My rod separated from the gray valve at one point. There was still enough of the valve stem protruding from the gray valve to crawl under and pull it with pliers.
I found that the rods used on valves do not seem to be very strongly attached to the stem. Over time the force of pulling the rod can lead to separation. So -- frequent lubrication can alleviate the force used and presumably extend rod life. Second, separation may be at worst point but the failure is not catastrophic in my experience.
Crawl under and carefully investigate how your system works to determine what might happen in a separation. You will probably have to do some re-engineering on the rods if you really want to avoid the risk of failure.
