A fairly detailed video on how to rebuild an MQB elecontric rear parking brake caliper on a 2013 Audi A3. Should be the same for MQB based cars!

Timestamps :)
0:00 Why
0:09 Wheels Off
0:35 Winding Back Electric Caliper
1:21 Brakes Disassembly
3:04 Clamping Brake Line
3:42 Caliper Cleaning
4:15 Caliper Teardown
4:26 Warning Message
4:52 Caliper Teardown
5:07 Caliper Boot Removal
5:29 Bleeder Screw Removal
5:46 Small Parts Inside
5:56 Slider Boot Removal
6:09 Paint
6:15 Replacing Orings
6:47 Piston Reassembly
7:49 Piston Boot Install
9:13 Securing Clip
9:28 External O Ring Replacement
9:36 Slider Boot Install
9:49 Electric Motor Reinstall
10:02 Bleeder Screw
10:12 Caliper Reinstall
11:54 Bleeding Brakes
12:45 Resetting Parking Brake
13:53 Final Painting
14:01 Reassembly