AGENT GMD500+SHOWA IX110 lock case, lock defect inspection

"Sometimes it's hard to lock."

This is an apartment that was built 35 years ago. It was written on the internet that it was made of lightweight steel, but it doesn't seem like it from the outside. The exterior walls appear to have been repaired several times, but the area around the entrance door has only undergone some renovation. The interior had been renovated, so only the entrance door was old and had deteriorated over time.

We were able to confirm that the pull-leg screws were loose and the area around the lock case was dirty. Completed by disassembly cleaning and locking treatment. There was no click feeling from the lock case (some of the springs may have been weakened), but if you turn it firmly, you can use it normally, so I decided to leave it as is and see what happens.