The Japanese company Shimano manufactures many bike components. Among its products is the 105 groupset, which is composed of gears, derailleurs and levers. The 105 is an older groupset in the middle range of quality. If you are overhauling a bike or want to upgrade your brake levers, you will need to know how to remove the old ones. The removal of the 105 brake levers is similar to the removal of any of Shimano's brake levers.
Remove your handlebar tape by pulling out the end caps from the ends of the handlebar, then unwinding the bar tape. As you remove the tape, roll it up to make it easier to put back on after you attach your new brake levers.
Detach the brake cables at the brakes and the shift cables at the derailleurs. Do this by loosening the bolts on the front and rear brakes and the bolts on the front and rear derailleurs with an Allen wrench. With the cable cutters, cut off the end of the cable where an end cap is crimped on. Pull the cable completely out of the bolt.
Push one of the brake levers all the way in. Looking from the front of the bike, you'll see a bolt that holds the lever clamp onto the handlebar. Use an Allen wrench to loosen this bolt. You don't need to remove the bolt, just loosen it. Repeat on the other brake lever.
Slide the brake levers off the end of the handlebar.
If you plan to reuse your cables, cut them as close to the end cap as possible. However, it is a good idea to replace your cables if installing new components.