How to Remove a Broken Key from a Pin Tumbler Lock
You may need to replace the driver pins in a pin tumbler lock. The pins are located inside the cylinder of the lock. To access the pins, the cylinder must be removed from the lock. On most cylinder locks the plug is secured with a circlip. When the circlip is removed, the plug may be withdrawn from the cylinder. Take care when removing the circlip as it is easily damaged. If the circlip is damaged, they are readily available from locksmith supply stores. Use a plug follower, a brass cylinder the same size as the plug, to remove and replace the plug from the lock.
Step 1 – Remove the Plug
After removing the circlip and with the key in the lock, rotate the plug about 45 degrees. Now turn the lock so that the plug is pointing up. This is to avoid dropping the key pins out of the plug as it is being removed. Push the plug follower into the back of the cylinder and start pushing the plug out of the lock. Then the plug follower replaces the plug and will hold all driver pins in position once the plug has been fully removed. Make sure to keep the plug upright after removal to avoid spilling any key pins. It may be worth while to work over a bath towel to prevent the small pins or springs bouncing away if they are accidentally dropped.
Step – 2 – Changing the Driver Pins
The plug follower will have to be removed from the cylinder using great care as the driver pins and their springs will be forced out of the holes as it is removed. Consider removing the plug follower inside a clear plastic bag which will catch all parts when they emerge. Carefully put aside all springs and pins that are removed. Replace the desired springs and pins from the kit and prepare to reassemble the cylinder. This could be tricky.
Step 3 – Replace the Plug
Turn the assembly upside down with the 5 spring chambers facing down and the lock facing you. Push the plug follower into the back of the cylinder just before covering up the fifth spring chamber right at the rear of the lock. Ensure that the groove at the end of the follower faces inwards. Using your fingers or long nosed pliers, place a spring into the groove at the end of the plug follower. Press the spring gently into chamber number 5. After this has been done insert a pin in this groove. The pin won’t be able to enter the chamber because of the spring so use a narrow screwdriver to push it into the spring until the pin is level with the edge of the cylinder. Now push the plug follower in, to keep the spring and pin in place. This process should be repeated for all of the pins and springs. Once this is complete, replace the plug pushing the plug follower back and keeping the pug upright without spilling the new key pins. Reassemble the lock and check the key.