I am attempting to re-assemble a mountain bike for a friend that won it "pre-assembled" at a fundraiser auction. It is one of those nasty, cheap full suspension bikes. Michelob Ultra full suspension. These keep showing up on Craigslist as "1 of only 300 ever made" collectors bikes non-sense.

This one is brand new out of the box and slapped together for the auction block.

The issue is the disc brakes. They are labeled "YUS" and that is all.
These appear to be a Yusheng YDS-11 brake caliper.


The problem is, there are no assembly instructions for the bike and the caliper does not move when the lever on the caliper is moved. The lever moves freely but the piston does not even hint at compressing.

I am about to disassemble the caliper and was hoping maybe someone has looked at and has some clue about these calipers.

Attached is an example picture of the bike in question:
Michelob Ultra bike.jpg