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Upvc back door won't lock

Hi, problem locking my back door - the bolting mechanism seems to work fine, ie. when I raise the handle the 4 bolts go into their correct positions but the key will not turn enough to lock the door. Seems like there's an obstruction of some sort stopping the cam (think that's the correct term?) from rotating in the cylinder. Have replaced the cylinder with a new one but to no avail. Also, tried to remove the brass strip that runs the length of the door to try to see what the problem is, but I need to remove the 4 locking bolts to release the strip and they just keep turning in the door when I try to unscrew them with an allen key. Seems like they are not threaded, which is a bit puzzling to say the least?

Any help much appreciated

Sorted! :) The problem was with the locking mechanism that's attached to the brass strip mentioned above. I managed to remove it from the door by simply undoing all the screws - doh!... then checked the locking mechanism - didn't really know what I was looking for, but as luck would have it a very small piece of metal dropped out. Wasn't sure at first if the piece of metal had broke off something important in the mechanism and I would have to buy a new one. Thankfully it did not, and once replaced the lock worked just fine. :) Obviously the piece of metal must have been the cause of the lock jamming.

Thanks very much for the responses. Hopefully the above will help someone else with a similar problem.

4 Answers from MyBuilder Window & Door Fitters

Best Answer

As the last trade has said, the door probably needs re packing. Easy way to test door lock is to open door and try locking it in this position if it locks then that is fine, so you will need to toe and heal it. You may want to call on a local installer to do this if you are unsure.


Answered 23rd Oct 2013

Hi, try and toe and heel your door, take your glazing beads off the inside of the door. Look on the side where the handle is, you will see packers on the top and sides, try and get a couple of packers and lift on the handle side about 3-4mm and if the door will lock then, make sure you don't use anything metal to lift the door and check to see if any packers have slipped down the side of the glass.


Answered 24th Jun 2013

Without looking at this it's hard to say but given previous doings with this type of problem it will be to do with the locking mechanisms with the bolts as mentioned. It's clearly not the locking mechanism as you stated you have tried a new one. I had 2 jobs last month and both turned out to be the locking nuts. I altered them with an allan key and eventually the door was able to lock so personally you need to have a play around with them till the lock turns and locks properly (it's all down to having to be bang on with the locking mechanisms for the door to work correctly)


Answered 24th Jun 2013

The door probably will need adjusting. You say something has broken off from the locking mechanism it could have broken off from the gearbox, this is in the centre of the locking strip. You say there is an obstruction when you turn the cam, I think the gearbox is at fault.


Answered 24th Nov 2015

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