if your brakes are like the ones on my '89 240 (and I'm sure they are), you
don't have to disassemble the caliper at all.... just use use a C-clamp or
large channel-lock pliers to force the existing brake pad backing plates
away from the rotor (to push the pistons into the calipers), then drive out
the two pins that hold the backing plates in place. The plates (and
remaining pads) will slide out. Replace with the new ones, slip them back
into place (always harder than it sounds), fit the pins and the springs back
into place, and that's it! Caliper stays intact, although I always find it a
good idea to get a friend to help me go thru bleeding the brake lines every
year or two, just so there's fresh fluid in the system to prevent
corrosion....

Remove the lower pinch bolt on the caliper then slide up out of the way

You don't have to disassemble the caliper, on my 740 with ABS you take one
one bolt and the caliper flips up IIRC.