Quoted from cooked71:
That magnet is way too low. Should be flush or a fraction above to prevent wear on the edge of the pf. It's a pretty simple adjustment but you'll likely need a big wrench to loosen the nut under the PF, and a big flathead to twist the magnet.
Might also be a good idea to warm the locking nut with a heat gun (on LOW setting) if it is very stiff. They sometimes have a lot of Threadlock on.