I had the same issue with mine , i solved the pb once and for all by drilling the part holding the clip and then threading it to get a screw fitting there , a little thread lock on top of that and since 4 gallons not even one screw came loose or flyed awayhere is two pics on how looksonce done .
In fact i used a lathe to drill the part to be accurate but i guess that a simple drill and a little patience should do .