How to remove/change a roof rack barrel

Most roof rack barrels can be removed to allow you to replace them (i.e. if you want matching keys). To change a barrel your need 3 things:

With the change key, simply insert it fully into the unlocked lock and gently pull the key. The barrel should get pulled out with the key. Once the barrel is out remove the change key and insert it into the new barrel. Replace the barrel back into the housing. Once in use you finger to hold the barrel in place so you can remove the change key. Insert the new key to test it.

Roof Box locks are a little different that they are held with a clip or a nut from the inside of the box. You need to open the box and use tools to remove the clip or not and the lock will come out from the front.