Alrighty, so there's a bug going around and it had me good and knocked out earlier this week. Being home all day, I tried to pick myself up and get some stuff done. Luckily RockAuto ships at lightning speeds so I had the o-rings and idler arm available to work
Right away, I could tell by the rust pattern on the disc that something was wrong with this brake. Looking closer at the caliper it looks like BOTH of the larger pistons were seized in position. This is weird because I am 100% not gentle with my judicious application of force to that brake pedal, but I digress.
Right about here I noticed something was amiss... Two different sized pistons, but all four of my o-rings in my rebuild kit were the same size.
I verified the part number versus what I ordered in RockAuto and in doing so, I discovered that I ordered the ONLY kit that was marked "42mm pistons only".
And because I ordered two boxes (one for each side), I now have a lifetime supply of half-caliper rebuild supplies.
yay me.
Since the smaller pistons weren't seized, I used their original o-rings and just gave everything a good cleaning before putting it all back together. This is when I discovered the dust boots in my kits didn't fit either (strike two?). So of course I cleaned up my original ones and put them in as well. Luckily I was careful not to damage anything when I took it all apart (I'm learning).
In the end, it looked something like this:
Once bled, I gave the pedal a good stomp.
op checks good.
I pushed all the pistons back on the right side as well. Everything looked good so I opted not to take it apart unnecessarily.
Good times.