The front door is upvc (newish - I have just bought the house from an estate of deceased person so no-one can help from vendors!)...Keys/lock worked fine for 7 days but now I cannot remove the keys (either inside or outside) unless the door is locked. So, if I unlock the door from the outside I can get into the house but then cannot remove the key unless I use a spare key on the inside to lock the door then go around the outside of the house to recover the initial key!! I have tried many permutations of lock/handle/key position (inside and outside) all to no avail. I am really perplexed by this. Can anyone assist or suggest a remedy? Thanks.

Peter Rawlings, August 2010

There are 2 reasons this might be happening. You might have a slipped cam on your cylinder lock. This can be corrected, but it might happen again, so it is best to fit a new cylinder. The other cause could be a faulty gearbox. This is the mechanism that the lock fits into. They do break and they cause problems in removing the key. If it is the gearbox, the complete locking mechanism strip has to be removed from the edge of the door and the gearbox can be replaced. They are normally held in place by torque head machine screws. You would normally have to order one of these from a lock company or a upvc door/window company.

Phil, August 2010

you need a new barrel.
on the lockstrip (on the edge of the door) there is a retaining screw directly in line with the barrel, remove this. turn the key a quarter turn and pull out the barrel.
measure whole length of the barrel, then measure from screw hole to both edges. for eg. 50mm/40mm 45mm/45mm 45mm/55mm and so on. b&q or screwfix sell euro cylinders although you will get the exact size online. building plastic firms also have them. you can use a different size barrel but don`t use a smaller one as you may not be able to get the key fully in, a larger one will stick out further from the handle plate.

levilewy, August 2010