One quick question. Is there any interference between the lock lever and the floor mat? I have had issue with just the slightest contact of either the floor mat or the padding underneath the mat. Those lock bars can be finicky.
I strongly urge you not to alter the lock bar in any way. Hopefully someone who had the truck before you didn't alter it, causing you the difficulties you are having.
You can try removing the paint from the curved, round pedal rod to allow the locking bar to have a better bite upon it. The force which makes this apparatus work is friction between those 2 parts.
Carl
