The problem is If the fluid ever got too low you'll get air Into the abs block. There are two procedures to run to activate the abs block and the abs pump. I'll look in the PDF Repair manual and see if I can find the process.

1. Connect BMW Diagnosis and Information System (DIS).
2. Call up service function Bleeding ABS/DSC3 Hydraulics.
3. Connect bleeding unit to expansion tank and switch on.
4. To flush system completely see FLUSHING BRAKE SYSTEM COMPLETELY.
5. To only bleed front or rear system see BLEEDING FRONT OR REAR-AXLE BRAKE CIRCUIT.
6. Switch off bleeder unit and disconnect from expansion tank.
7. Check brake fluid level.
8. Close expansion tank.

Flushing Brake System Completely

1. Connect bleeder hose with container to bleed valve on rear right brake caliper.
2. Open bleed valve and flush until clear, bubble-free brake fluid emerges.
3. Close bleeder valve.
4. Follow same procedure at rear left, front right, then front left calipers.

Bleeding Front Or Rear-Axle Brake Circuit

1. Connect bleeder hose with container to bleed valve on right brake caliper.
2. Open bleed valve.
3. Run bleeding routine with BMW Diagnosis and Information System (DIS) with bleeder valve open.
4. After running routine, press brake pedal 5 times to stop. Clear, bubble-free brake fluid must flow out.
5. Close bleeder valve.
6. Repeat procedure at left caliper.

__________________
2011 E70 • N55 (me)
2012 E70 • N63 (wife)