Trunk lock problems, how to fix?
 

My trunk lock is difficult to insert the key into, and very picky about how deep the key is inserted to allow unlocking/locking. Is this a disassemble and clean fix, or a replace fix?

Probably a combination of worn key and dry lock tumblers. Key depth usually is a miscut replacement key. Hard to insert is a dry lock. As with any lube issue try WD 40 first!

Tried a generous dose of WD40. A little better, briefly. I'm thinking disassembly and proper lubrication may be the best route.

Disassembled the lock, cleaned dried grease and lint out, found one pin missing, and destroyed the spring that holds the ball during assembly. Ooops. It works better now. It will lock and unlock with the key fully inserted now, but is still catchy. I think it's just worn out.