Sometimes it's easy to remove cotter pins and sometimes it seems like they are holding the entire car together. You pull and bend and twist, using a strong pair of pliers, and it takes way too long to get the pin out. You've even managed to break perfectly good needle-nose pliers by trying to get a cotter pin out, haven't you? What to do?
The chief reason a cotter pin is hard to remove is because you are pulling "in line" with the pin. Any bends or twists in the pin lodge it in its hole. What you need to do is use leverage, and that means you need to convert in-line motion to 90-degree motion.
A way to do this is to use the old-fashioned, seldom-used drum brake tool. You know the one! It looks like a weird pair of scissors that has a sharp point on one end and a bent spiral on the other. It has long arms that pivot, to provide lots of leverage for those tough brake return springs.
Position the brake tool so that you can grab the cotter's eyelet with one end or the other, then use the leverage of the scissors-action to help pull out the pin. It works!