Side shaft bolts loosen - how do I lock them in place?

Hey guys, 

I tried three times to lock the side shaft bolts (wheel side) in place, using loctite and new spring washers. After a couple of hundred miles, they loosen up again. Did someone have the same issue in the past and how did you fix this? Is there a certain orientation of the side shaft flange neccessary? 

Space is tight, but I managed to fasten the nuts with a long extension ultimately. Maybe they hold better now. 

BR