Unsensitive Control Buttons

[BluePhirePB]

Hey guys. I got an older Microsoft Sidewinder Racing Wheel (non FF) and tonight when I was playing Carbon, the shift down button on the back of the left of the steering wheel started to malfunction. The button is become non-responsive and it's causing me to have to push really hard on the button to downshift now. I've had this wheel since Underground and I take good care of it. My question is, how can I correct this problem? Can I take apart the wheel and add an extra layer of paper or something under the button to correct this problem or should I invest in a new wheel?