Strange Clicking noise in ps2......

[gaijin]

I've recently started having this problem and I did a little errortesting on the ps2. The problem I have is that the piece of plastc that connects the laser tray to the arm running it doesn't connect well. So what happens is that it sitts on top of the marks where it should run, hence the clicking sounds.
I push it into place and it works for a while, maybe one two hours but then it jumps off again and I have to open the damn thing and fix it again.
Any ideas on how to fix it? Doesn't feel like a problem that should cost 35$ to fix.