FSA crank bolt won't stay tight
I've probably posted this question before, but I'll ask again. How do I get the crank bolt to stay tight on my FSA SL-K Mega-Exo crank? Last year when tightening it on the road I actually broke the bolt. The replacement from FSA just doesn't stay tight. I've used a torque wrench on it a few times, but I don't carry that on the road, but it hasn't helped in any case. I tightened the bolt last night for a quick 15 mile ride, and when I went out again tonight my crank arm was ready to fall off again.
Should I try Loctite? And which one? Should I try some kind of lock washer? I know the later models came with a wavy washer, but when I asked FSA they said that my model doesn't take one. There's also the issue with the self-extractor. Since it is also normal threaded it will come off with the bolt, and I lost the original. The later model reverse threads the self extractor.
And a different issue, but also with the crank I think. I bought a derailleur alignment gauge and I used it and now the derailleur is straight and parallel as it should be and is quiet, but I get a lot of chain chatter on the crank. What's the best way to quiet it down? The gear is Chorus 10, except for the FSA crank.