Originally Posted by ALFIEV

So, I have epoxied an aluminium plate onto the back of the firewall, used large fender washers to spread the load of the tightened bolts on both sides of the firewall, and I bored the holes right through the stand-offs so that I can fit a bolt all the way through from front to back and put a nyloc lock-nut on to secure it. I have flown it since and these changes seem to have cured the problem.