brake pads
 

how am i supposed to remove these pins holding the pads?
I removed the M shaped spring holding the pins, but the pins seems to be stuck. any tip?

The M-shaped spring is the only thing holding them in, other than perhaps rust. The pins are supposed to be free sliding. Mine come out with nothing more than a simple push.

You may want to hit them with a little (not a lot) of a rust breaking compound, being carfeul not to get any on either the pads or the discs. Try tapping gently on them. You can apply a tiny amount of grease on the inside of the holes when you put the pins back in, being careful to wipe any excess off the pins. Synthetic grease would be better. Also, grease the caliper slide bolts (the ones with the rubber bellows) while you are at it.