Did a search and couldn't find what I needed. I have a Porter cable and bought some new pads (cobra cross grove) and the pads keep falling off? Even if I just hold it upside down. I tried a couple of my older pads Lake Country pads and they are not staying on either. Is my backing plate wore out? I have only done about 6-7 cars with it. It is about 6-7 years old though. Am I doing something wrong or should I try a new backing plate?