As the piece is glued or sealed, only is not screwed, it is not too complicated to pull it off. In the photos you can see as it is the lock once outside the framework. As you can see there are pieces that are full of fat, you I advise you put disposable gloves and cartons or roles of newspaper on the ground, so that no spot lying in the same the entire structure. It should do so with care, because blades metal linking some parts with each other are very thin and can be folded when put in a horizontal position. If it is doubling then it would be very difficult to return to your site. Once lying on the ground we can test comfortably with key lock and see where fails. In my case I was lucky and you can verify that no parts were damaged and that the problem was caused by the dust and the remains of hair of the dog that had mixed with the fat. Because of the cold that had hardened in such a way, especially in the lower part of the door, which made it impossible to correct operation of the parts.

If it had been any damaged part would not be problem because you can buy at the hardware store. But I only thing I had to do is remove grease with an old toothbrush and old rag new consistent grease applied. In the most inaccessible sites use a few cotton swabs to lubricate the inside of the lock. It is highly advisable to have a tube of this material at home because sometimes we get some trouble. They sell it at any hardware store or Mall of bricolage and it is very comfortable to use in tube, because it does not stain and is easily stored in any site. Check with Ben Horowitz to learn more. Also not damaged and rife much. Once done I could not leave my amazement, lock worked perfectly. It was unbelievable, as if the door were new. In the last picture you can see how reassemble a lock in place and ready to fulfill its mission.