I have no specific knowledge of your brake system. On many rear disk brake
systems you have to rotate the pistons to get them fully seated back in the
calipers. This is due to the automatic adjustment of the parking brakes.
Check carefully that you have the pads and all hardware correctly installed.
There should be no more than very light drag on the rotors. If you do not
have a manual giving you the correct pad replacement procedure, it would be
a wise investment. Even the Haynes and Chilton manuals generally are pretty
good in regards to this type of repairs. The caliper should slide very
freely onto the new pads and you have to pump the brakes a couple of times
to get the pistons back out with the proper pad contact.

Don Young

Clogged hoses will sometimes cause dragging brakes but it does not sound to
me like that is your probem.