Slightly jumbled inputs on right stick.

I have one of these controllers, but when I move the right stick above half way while it's in analog mode, it registers the R3 button as pressed too. When I press the R3 button, it also registers the stick as having been moved to the top. I've tried cleaning out the stick mechanism with contact cleaner and I've checked for any bridges between the pins that connect the sticks to the main board. Is there a way to fix it without replacing parts and, if not, where can I get the replacement parts I need?