My drivers side door lock will lock but will not unlock by using the key. I took apart the door and it seems that the end of the lock spins for alil bit before the " tear drop bracket" on the back of the lock turns. I think this is what is causing the rod to not extend downward enough to lock the door. Question is it the lock or the bracket?? please help.

 

It sounds as if the lock cylinder or cam plate is worn. A bit of linkage rod adjustment might get it to work a bit longer, but finding and curing the excessive lash problem would be the best solution. You might consider changing the four body lock cylinders with new ones. They are often sold in kits.