The passenger seat of my 97 855 is rattling. I tightened all of the bolts at the hip joint, but am still getting a rattle. This passenger seat folds flat (the one in my 95 didn't, but it also didn't rattle) so I think it may be to do with that. I folded down the seat and then put it back up to make sure it locked in place - still rattling. Has anyone traced this one down and solved it?