Sliding gate not opening or closing completely Posted on September 28, 2019September 28, 2019 by wwilder Sliding gate not opening or closing completely If you have an automatic gate operator and a sliding gate that isn’t opening or closing completely, a close inspection of the roller drive chain will often reveal the problem. CAUTION NEVER TOUCH A CHAIN OR SPROCKET DUE TO RISK OF INJURY When the chain begins to rust it may not fully engage with the gate operator drive sprocket. This can result in the chain jumping teeth on the sprocket. You might have experienced this phenomenon if you ever had a very loose bicycle chain. The difference here is the gate operator is designed to start and stop based upon the chain staying indexed to the sprocket. If it jumps teeth when either opening or closing, it will close too far hitting the post or it can open so far the gate actually passes through the overhead guide rollers allowing the gate to fall which can be dangerous. If the chain has failed on your gate operator due to rust please contact an experienced service company to correct the problem. More about chains: Never use WD40 on your gate operator chain because it will wash away the lubricant causing premature failureMost lubricants for garage doors will work just fine.