Front Brake Lever stuck (as a Rock)

[German Larrain (Chile)]

    Just to share an experience, where 911 GS couldn't diagnose an ABS/Brake serious problem.
R1200 GS 2010, suddenly front brake lever got stuck, if I press, it just doesn't move, hard as a rock, plus that the front brake doesn't work at all. First thing tried to bleed the circuit, at the caliper front wheel, the result.... no brake fluid coming out.
I ran 911 GS Auto scan and it doesn't show any fault. I tried the ABS Output test and perform test at all elements, including Solenoid Valves and everything is OK. Tried also the bleed test, and nothing changes, the lever cannot be press, stays firm as a rock. I checked the lines, everything OK. The last possible cause is that the hydraulic portion of the ABS modulator is block . Given this unit hydraulics is sealed, the only way to find out, is  to replace with a good ABS unit and see how it works.
Bingo...it work, the brake lever was actionable again, allowing to bleed the ABS and make the front brake works again. The final cause was the INLET front Valve/Passage was blocked. Even 911 GS was able to action ( three clicks) the corresponding solenoid valve , at the Output Test, it didn't mean that it fully open the valve, so the brake fluid can run free. The most probable cause that an obstruction was produced by a debris or so, and it simple block the fluid to run.

[Jughead]

Yes, the GS911 is unable to diagnose mechanical faults.  There is no diagnostic tool in the world that can do that.

The GS911 can only report what the ZFE/DME have logged as errors.

The fact that the solenoid clicks when tested only reflects that the activation circuit is functional.  It does not mean that the mechanical parts connected are actually functioning as it has no way of determining that.

I have also had a case where the lever was solid with no braking power on the wheel.  In this case the client topped up the fluid using DOT5, which is silicon based and not compatible with the DOT 4 in the system.  This caused the rubber seals to swell and bind, preventing the plungers from moving.

[German Larrain (Chile)]

Thanks for the comment, good input. Probably that's what happen in this client's case. I didn't realize, at first, that DOT 5 can harm that bad, the break fluid elements inside the ABS unit.
Thanks

[German Larrain (Chile)]

          Interesting, somebody shared his experience, where GS-911 was definitely part of the solution. Again, same symptom, front break lever hard, solid. With GS-911 through OUTPUT Test functionality, he actuated the Inlet Front Valve several times, when suddenly the valve release the pressure and now the brake lever can be press and front break start working. The logic here is, although the valve it's a mechanical device, through several valve test, it opens and start working as it should and save some money,