sliding door - can shut or lock but not both

[ambivert]

The lock stopped working - the lock lever simply wouldn't operate either via the key or the black button inside. Something was getting in its way.

It seemed like the bowden cable (which runs from the door handle to the rear catch) was at fault... it was too slack so I adjusted it. This pulled the mechanism along a bit and whatever was blocking the lock moved out of its way and let it work.

But yesterday the door stopped shutting, it just bounced straight open everytime I tried. When I did it slowly from inside I could see that the rear catch wasn't closing, because the bowden cable was now too tight and pulling it open.

So I slackened if off some... But now it won't lock !!!
As I tighten the cable up, to be able to lock it, it becomes un-shuttable way before it becomes lockable.

Something in the lock must have worn out or broken for this to be occurring...? Anyone got any ideas what it could be, before I start pulling it to bits?

As a temporary measure I have left it slack so I can at least shut it and have fitted a padlock

[asahartz]

Take the rear catch out and lubricate it. Mine used to need a really good heave on the handle and a bone-shuddering slam, after lubing the catch it's much easier both ways.