Hello I have an 06 530xi, both my rear brakes are locked up. I’ve taken both sides apart and checked that the piston seals aren’t bad, they don’t move when I have the fluid cap off but they move when I open the bleeder valve and fluid flows out fine, I’ve disconnected the ABS module as well as pulling the abs fuses and still nothing. The pedal doesn’t stick and isn’t harder to press than normal. I’m trying not to replace the master cylinder but that seems like what’s going to end up happening, is there anything else I could try to do before I end up replacing everything?

 

Have you tried to put pressure to the fluid reservoir and open the bleeder?

 

Yep, came out clean