"ss" wrote in message
...
On 30/07/2018 09:40, Brian Gaff wrote:
Proper oil, not wd 40. Oh and push pull the loop bit a bit and give it a
major clout. However if it does unlock, I'd most certainly replace it.
Brian

My understanding is that most of the internals are made of corrosion free
or brass parts (apart from the springs).

Yes.

This being the case I doubt if it has seized, more likely to have a worn
pin or key which would prevent the key from turning.

Much more likely that the pins arent moving as freely
as they used to due to dirt in the lock and so they dont
slide down to the key properly, and so dont line up at
the edge of the cylinder anymore, so the lock wont unlock.

Powdered graphite fixes that and it then works fine again.

If the key insert ok then the springs will be free and not seized.

But the; pins wont necessarily slide freely.