[squirrel_hunter]

I've always split the caliper to do the piston and seals.

Tip wise those bolts should be torqued up (can't remember the setting) nicely coupled with the fact they are made of special metal cheese makes maintenance fun. Clean them up first before attempting anything, and if you use it every day have spare bolts unless you don't mind riding without a rear brake.

Not tried an impact driver on these bolts yet as I don't have the correct size bit. The last time they seized on me I had to take them to my mechanics, they had to use heat and sweat to get them out. The next time it happens I will be looking at the Dremel and the impact driver.

Now this might sound silly but as your changing the pads its easier to have the caliper mounted correctly before attempting those bolts. I once took the whole caliper off before I decided I wanted to split it and had a bit of fun before I stuck it back on the bike!