PR.PGF704+B5 Key does not stick, pull out, or turn

"Entrance cylinder malfunction, inspection and repair"

The key doesn't stick and sometimes doesn't come off. It seems that the symptoms are getting worse.

After confirming the phenomenon, I decided to perform normal disassembly and cylinder cleaning work.

It is an old push-pull grip handle lock with a large arch shape. The new model is a U1 type security thumbturn, but the old model is a B5 type security thumbturn.

When I disassembled it, it was covered with dirt due to aging. It has been cleaned and improved.