VW Passat B6 – EPB Caliper – What is inside?

Almost all modern cars come with EPB (Electronic Parking Brake) Systems.

This part failed on a 2008 VW Passat B6.

What are the visible faults:

  • plastic case for electric unit has visible cracks that allow water and contaminants
  • brake piston is seized
  • brake fluid really dark and gel like

Now let’s do an exercise and try to understand how and why did it fail.

Trying to answer this question I find myself asking what failed first?

Did the plastic case crack and let water inside that seized the brake piston or maybe it was the other way round?

First the brake cylinder seized and because of this the electric motor managed to snap or twist something? This is very unlikely as we don’t see any grinded parts, but we see the plastic gear being seized.

At this point I give up and let you think and find more information.

Hopefully the photos and video helps.