5-lever mortice lock occasionally jams

You should be able to disassemble it completely. Just make sure you keep the levers in the same order. :)

Era dealocks usually have 3 small crosshead screws keeping them together, but I've only taken them apart to confirm they are not worth repairing. Take a photo asap after dissassembling.

There should be no problem dismantling a lever lock. Just do it carefully, in case you disturb a spring under tension, though most reputable locks won't have that problem. As always, take some pictures.

The general recommendation for lock lubrication is something dry, either PTFE or graphite. You can try spraying that in the keyhole, but I'd advise dismantling and cleaning, there will almost certainly be some dust build-up, and the pivot for the levers is usually well away from the keyhole.

While the cover is off, try the worst of the keys you have (again watch the springs) and you may be able to see where it is sticking, or has very little clearance. Try it from both sides, as locks are often not perfectly symmetrical.

I know some will oppose the idea but I would use a silicone oil spray. If there is a gummed up part then a dry lubricant isn't going to have any meaningful effect.

They are simple to take apart and clean. They also wear such that some keys work better than others. Best copy a key that works the best!

I wonder how old and how well-used the old lock is? I'm sure they must wear out eventually. I'm beginning to wonder the same thing about my

For what it's worth, the cost of a replacement lock will be fifty quid or a lot less. Extra keys come in at seven quid each or less. Nuisance value of changing everything notwithstanding.

Coming home late at night with the family and all of you being locked out with the only locksmith willing to come out primed to charge you a fortune would not be much fun - see the prices in the story here...

Strip it down and see what it's like after you've tried some maintenance as suggested by the others in this thread but if you have any doubts about it after that, I would replace it - or get digging down into the flower beds!

Nick

you're right - some WILL oppose it

spraying anything through the keyhole is a waste of time

take the thing out and dismantle it, and wash all the crud off with some petrol or some other solvent, then let it all dry.

When its completely dry, just reassemble it using some powdered graphite (theres loads of it on eBay)

One of the advantages of dismantling is that you can confirm that there isnt a broken spring on one of the levers.

I suspect that the actual problem is that a couple of the levers are sticking together

Being cautious, I always remove the key from the other door into the house (which has a modern deadlock that uses a Yale-type key) so my key will actually unlock the door. For some reason with those locks, a key will go all the way into the lock from the outside but if there is a key on the inside the lock won't turn.

We're planning to replace the door that has the Era lock at some stage, as part of remodelling the frame and the windows either side, so I'll try carefully removing the plate from the lock and see if I can spot any gunge that needs to be removed, or lubrication with powdered graphite, to keep the lock going until then.

But it's so quick and simple to do that it's worth doing it first anyway. It may do nothing, as you imply, but it just may solve the problem.

ok - so a waste of not much time ?

Replace the lock. We’re on our third mortice lock in about 30 years. They don’t last forever and whilst you can open them up and do a bit of fettling it’s a lot easier and more reassuring to just fit a new one. I find the automated key copying machines do a much better job than many key cutters so it’s worth getting some spares made at the same time.

Tim

The whole point of a fine spray is that it gets everywhere inside a lock mechanism. There really is nothing to lose.

I agree, but if the problem is a broken or misplaced spring on one of the levers then you are not going to find out by doing that

I think that you are in effect confirming is that a spray can un-jam a mechanism but if the lock still fails to work there is likely a component failure.

In which case the OP is advised to simply change the lock rather than open the lock that is not designed to be repaired and has no (easily) replaceable parts.

If that was true then they would assemble it with rivets instead of screws

uk.d-i-y, right?

Changing a lock is DIY. Well for some at least. I regard it as a trivial process.

I would be taking the lock apart out of interest if anything but conscious a replacement is perhaps a better solution than trying to fix something that is heavily worn.

YMMV

I recently took a lock apart and found one of the springs has slipped out of position. I persuaded it back into place and re-assembled (lubrication judiciously applied whilst I had the thing open). No further problems - and I am a fairly fumble-fingered occasional DIY-er.

After all, if it hadn't worked, I would then have to buy that replacement - so there was no good reason not to at least have a go.

Heavily worn? That could be the case I suppose - but you can only determine that if you take it apart.