Cv Joint bolts loosening

Got a small prob with the bolts holding the CV joints in constantly working loose.
I've been lock tighting them and tightening as far as I dare- still coming undone.
The axles seem to be the right length ( I guess) as at rest i can moove them back and forth by about 5mm.
The bolts themselves are aftermarket ( not genuine VW) Is this the problem?

Do you have the little wavy washers under the heads of the bolts?

The bolts themselves are aftermarket ( not genuine VW) Is this the problem?

go and get some S/ Hands one and make sure u fit the wave washers

tighten the evenly as well

Thanks guys, now i've got a project for tommorrow.

You also MUST have the bridge plates under the serated washers.