i. Removing the circlip
On most common deadbolt cylinders the plug is held in place with a small ring called a circlip. This ring has a gap in it that allows the circlip to be expanded slightly and removed from the plug. With the key inserted (or the lock picked) and the circlip removed, the plug is free to be pulled from the shell. There are a number of commercial tools available that will make removal of this circlip much easier. You can also remove them with a careful hand and a small, flat head screw driver, though caution must be exercised not to break or badly bend the fragile metal. If a circlip is damaged beyond repair they can often be purchased from a local locksmith or locksmith supply company.
ii. Removing the plug
With the circlip removed and the key inserted into the lock, turn the plug approximately 45°. Next, rotate the lock so the plug is facing upward. This is important so you do not drop the key pins from the plug while removing it. Line up your plug follower with the rear of the plug and begin to use it to push the plug out the front of the lock. The plug follower will replace the plug in the shell keeping the driver pins trapped above the shear line. Be careful not to drop the plug as it leaves the shell, or to tip the plug dropping the key pins. You may find it useful to do this over a kitchen or bath towel on your table or workbench. This way, if any parts drop they will not bounce or roll away.
iii. Changing the key pins
With the plug removed you can gently tip the plug and spill the key pins out onto your towel. If you wish to reassemble the lock in working order be sure to note the order in which the key pins are removed so you can replace them in their appropriate chambers. If you wish to re-key this lock to work with a different key you would need to have key pins that correspond with the bitting of the new key (more on this later).
iv. Changing the springs or driver pins
On occasion, you may wish to change the springs or driver pins in your locks. This can be accomplished by removing the plug follower. Be careful! Because the springs are under tension the driver pins have a tendency to spring out with unexpected force. It is probably not surprising to hear that it is not very fun crawling on hands and knees looking for a stray pin or spring. You may find it helpful to hold the lock in a large, clear plastic freezer bag in order to contain the parts as they spring from the lock.
Once the driver pins and springs are removed be sure to keep track of all of them. Replace the components that you wished to replace and prepare to reload the springs and driver pins into the bible. This can be a tricky exercise. You may find it easier to do with a pair of long needle-nosed pliers. For this description we will assume that your lock contains five pin stacks.
Hold the lock upside down with the bible facing downward and the face of the lock toward you. Insert your plug follower from the back of the lock just slightly into the shell, with the groove in the end of the follower facing in, just to the point where the groove is in line – but not covering – the fifth chamber (farthest to the back of the lock). Either with fingers or pliers, drop a spring down into the shell so it lands in the groove on the end of the follower. Then gently shake the spring down into the fifth chamber. Once complete, drop a driver pin into the groove. The pin will not be able to drop down into the fifth chamber because the spring is fully uncompressed. Use a small flat head screwdriver or the blade of a standard tension wrench to apply pressure on the pin, pushing it against the spring and down into the fifth chamber. Once fully inserted, slide the plug follower forward replacing the blade that was holding the pin down and trapping the pin and spring in the chamber with the follower. Repeat this process for each of the remaining pin chambers, moving one step closer toward you each time.
Once you have loaded all five chambers you can reinsert the plug. Be careful to hold the plug upright so as not to spill the key pins. Align the plug with the follower and reinstall the plug just as you did in the previous section while replacing the key pins.