Dual 1229 Refurb - Tonearm Mechanism Question

Well, the bug had bit again and I have a new refurb project a Dual 1229. It's excellent condition but the tonearm doesn't work in auto mode. Fortunately there are loads of videos showing the process of sorting the problem and I'm almost there.

I have one question that I haven't been able to find an answer to though. How much movement should there be in the component marked in red? At the moment it doesn't move very freely.

Thanks in advance.