If it is a Trimark lock set. Once they start getting loose thats the first sign that you are getting ready to be locked out of your MH.
The older ones have a pot metal lever inside that fatigues and then breaks. Been there done that and if you do a search you will find numerous RV'ers that have been locked out.
You can buy a complete lock set just about anywhere on line. they even were nice enough to offer a 'real' metal lever to replace the pot metal one they thought they could get away with putting inside the lock.