[Omathisen]

Hi,
Turns out the sound is coming from the brake pads that move and out in the caliper. The sideways movement to the rotor is OK, but they are also able to move the other direction -- up against a cotter pin, to make that clunking sound.
Did something fall off (a spacer or spring to keep them in) or is this a sign of wear?
The calipers are Sierra, but I cannot find the model number.
Also, how do you open them up? The two big bolts on the inside?
I do not know much about this, so any help would be appreciated.
Thanks.