[Lil bastard]

There are different springs for the Base and the 'S', be sure yours are the correct type.

There are special tools which give you a mechanical advantage over the spring tension which work well. But, so will a pick or very thin phillips screwdrive. Place the end hook of the spring onto the shaft of the pick/driver. Then put the end of the tool into the hole on the shoe for the spring to use it as a fulcrum. Work the tool to expand the spring, bringing the end hook close to the hole and with your free hand turn the spring/end hook so it's oriented properly, push the end hook to the tip of the tool and simultaneously hook the end hook into the hole on the shoe while extracting the tool from the hole. It may take a couple attempts, especially if this is your 1st time, but I've used this method for many brake repairs and it will work.

BTW, if ever at an Antique Fair or such, keep an eye out for an old fashioned Buttonhook. These are pretty plentiful, cheap, and make excellent tools for pulling and installing springs of all sorts. I have one in my toolbox I paid $5 for and it's saved me a hundred times that amount in ease, speed, and lack of frustration on many repair jobs.