I have a R1200GS 2006 Model.
I have been having problems with ABS and brake failure staying on / flashing. After many hours of research the problem was the elect assist servo module with ABS. Because of the cost this is how to remove the module pump, re-plumb brake pipes and split the pump keeping the module intact to ensure brake switches and speedo still work.
1. Connect pipe from front master cylinder to front callipers. Use existing 4 way union, but use one side of the union.
2. Use existing pipe from union on rear frame. Cut, flare and fit new male brake pipe end into rear master cylinder.
3. Remove tank
4. Remove Servo pump complete.
5. Split pump and remove electrical pump connections from the hydraulic pump side. Reconnect multi plug and refit the module only using existing rubber mounting (i fitted a small cover over module and sealed to keep water out.
6. Bleed Brakes as normal and refit tank.
7. You now have it great brakes with no servo. Saving £1000 and it works !!!!.
8. I am working on extinguishing the flashing brake failure and warning light. I am thinking if splitting the dash and just removing the LED's. This is cheapest option.