This short instructable will guide you through the process of repairing a faulty mouse button. To do so you'll need the following things:

Materials

Button replacement

Tools:

Soldering Iron
Desoldering pen or pump

Notice this will probably void your warranty

Step 1: Troubleshooting

You have to make sure the source of the problem is not other except the button. If there was a more complex hardware problem it would be quite difficult to repair, since it would require SMD soldering skills. Software problems that affect only a button or two are quite strange.

In my case the scroll wheel button started to fail and it required quite a lot of pressure in order to make contact, I was totally sure the button was to blame.

Step 2: Take the Board Out

Open the mouse, if it's the first time be careful, you don't want to break anything or scatter all the pieces, take all the board either by removing the screws (if any) or by releasing the board from the tabs, this might be a bit tricky sometimes, so be patient, try to push the tabs with a flat screwdriver and pull the board out at the same time.

Step 3: Locate the Daulty Button

Locate the faulty button, in my case it was the middle button corresponding to the scroll wheel. But it can also be a the left, or right button, corresponding to those black box-like things at the top right and left.

Step 4: Desolder the Button

Heat your soldering iron at an appropriate temperature, nowadays many electronic devices use lead free tin, so you might need to rise the temperature a bit further. If you can't still melt the tin, melt some leaded tin over the connection, this will help to transfer the heat better and melt the solder blob more easily.

You might already know it, to desolder a component you have to heat the blobs holding it with the soldering iron, and then suck the tin with the desoldering pen, thy to place the pen at a 90º angle so the suction is stronger. I usually hold the soldering iron with my left hand and the desoldering pen with my right, it makes desoldering easier since I have more control over the pen.

After you've sucked the tin with the pen there might be some tin left holding the leg, try pushing the leg with a flat screwdriver to set it free. If you've desoldered the leg correctly it shouldn't be too hard to do this.