Suntour XC Comp Pedal issue

[bikewright]

I am out of ideas why this is happening. I have a set of Suntour XC Comp pedals. While rebuilding my 86 MB-1 the right pedal body would loosen up like the outside dust cap screw would back off. Found out the outside bearing was bad. They do not made the same letter# bearing today. I found a replacement bearing that works.

But I have the same issue. I can go ride a 1/2 mile and that screw will back off. I have tried 242 lock tight and that does not work.

Any ideas why this is happening?

I look forward to your ideas
Brian