When I was a young engineering apprentice, I noticed that one experienced milling machine operator always put a sheet of newspaper on the table of his machine and then put his vise on top of the paper.
He explained that the friction value of metal on metal was low and putting a sheet of newspaper between the faces very much reduced the tendency of the vise to slide from its position under heavy cutting loads.
Logical really, after all, we do not run metal upon metal in braking systems.
So my suggestion is that if you do not have opportunity to fit a positive adjustable stop for the outrigger, then just cut out a paper gasket to go between the faces. I can not claim absolutely that it will solve the problem, but it will definitely help.
Another thought on the subject is to scribe a line around the front edge of the outrigger on to the undertray after resetting the outrigger. You can then have a look after your ride to see if there is any evidence of movement. Kind Regards Roger
