Pads in contact with disk when idle on my SLX L675 disk brakes

Question

I've recently bought a Nishiki Hyper pro which features the hydraulic Shimano SLX L675 brake system.

What I've found is that the pads on the back wheel breaks appear to be in constant light contact with the disk. The wheel turns with no effort what so ever on the front wheel, but on the back wheel you both see and hear that it's a constant contact between the disk and the pad(s).

I wonder if, and if so, how I adjust this? I've Googled and looked around but don't seem to find the correct info I'm after unfortunately.

Brakes: https://drive.google.com/open?id=0Bw1M3VAfJAdzQk5YWVRKY2NsSzQ

Lever: https://drive.google.com/file/d/0Bw1M3VAfJAdzXzlRMEVrX1R2OXc/view?usp=sharing

Answer 1

Does the rear brake lever has spongy feel to it or longer throw? If not, you might want to manually rectract the caliper pistons:

1. Remove the wheel.
2. Remove brake pads.
3. Use something with flat non-sharp surface to slightly push both pistons (two white ceramic cylinders behind pads) inside caliper body. I usually use an allen key long arm.
4. Assemble everything back in reverse order and try it out.

If it didn't help and pads are still too close, it can be the case of too much mineral oil in the system. I had the similar issue when I overbled M615 brakes. In this case you'll need to open bleeding port (black bolt to the left of "SLX" print on lever from second photo) prior to step 3 and wrap with some cloth to catch extra mineral oil. After you're done pushing the pistons, screw the bolt back in and try the brake again.

As a side note, keep disc rotor and pads away from mineral oil.