MIWA U9.BH, disassembly and cleaning due to cylinder malfunction

"Sometimes the key won't turn."

It seems like he hasn't been feeling well lately. There are two locks on the front door, but the bottom one is not working properly. It is a defect that it is difficult to turn.

When I checked it, it was MIWA U9.BH (DZ), but it was upside down. With this, the direction of locking and unlocking will be different from that of the main lock. I often come across things installed like this quite often. It must have been a mistake by the door designer. I guess it's still on the market.

I checked the operation including the main lock, but the latch bolt of the LD lock also does not move easily. BH lock is cylinder operation defect. The hinges also make a creaking sound. It was the BH side cylinder that required disassembly. Other areas were usually improved with spray cleaning.