VW bike rack lock issue

[BristolCali]

I have a new (second hand) original VW T6 rack and regardless of what position the key is turned you can still tighten or loosen the clamps.

Before I ask for a refund I want to make sure I am operating it properly, should locking stop the twisting action on the clamp?

Thanks,
John

 

[royalv2]

When locked, the plastic knob should still spin but without engaging with the thread, so the clamp stays tight shut.

 

[bigmac77]

Mine did this on one of the arms, I sprayed a bit of WD40 into the key hole and it sorted it.

 

[BristolCali]

Thank you, I’ve removed them and cleaned and oiled them. All good now.

What size security torx do I need to fit the rack? I don’t have the original tool.
Thanks.

 

[Ch1pbutty]

It’s also worth removing the locking knobs, and then apply copper grease to the threads, then replace Knobs.