Re: Clevo Rear main cap
easy solution to your problem. By the sounds of it, you have put in a new neoprene rear seal. The little pin you are referring to was originally put there to locate the older rope style of rear seals, and yes it helped to stop them spinning. Neoprene was not invented yet, way back in 1970!
To fix your binding problem, simply grab some pliers and pul that pin out of there!!!! If you intend in always running a neoprene seal, you will never have a need for that little pin.