Working on garage door rollers is not a particularly complex job with the right tools and knowledge. First of all the door should be opened completely. A clamp is then placed on the track so that it is about two thirds of the way up. The structure is released from the power opener by pulling on the specialized release rope. It is advisable to unplug the opener from the outlet as an additional safety measure.
A pair of pliers comes in handy so as to bend the track near to top and open them accordingly. The first roller should be lined up with the opening that has just been created. A flathead screwdriver is then used to wedge the space between the track and the roller. This allows the removal of the roller through plying. The replacement roller should then be slid in so that it hangs onto the track. This job is best done in pairs.