This isn't right, anyone else's look like this?

[Cheesetoast]

the above pic is what this peice should  look like according to my mechanic, pushed in, you can push it in yon your own, but in a week or 2 i'll have worked it's way out again  (below pic). He says i need a whole new altenator bracket, anyoen else have this problem?

[MK3 GTD]

if you follow the tube that the shaft goes through it should go into the spring loaded tensioner which should have 2 allen head bolts holding it on to the alternator bracket and another smaller allen head bolt holding the shaft into it in the direct centre of the tensioner. check if any bolts are missing.

[Cheesetoast]

nope, no bolts missing, in fact my mechanic replaced that tentioner when i first got the car, was making a hell of a noise, said he had to 'fix' the bracket with epoxy too because the vibration had chiped away the bracket