The ABS unit failed on my 2004 (European) bike, with the GS911 revealing it to be a high pressure in the rear brake line.
I took the unit out (which was hard enough!) and dismantled the thing down as far as I could. It actually didn't look too bad inside, but I gave it a clean up and put it all back together.
Now, unfortunately, I am unable to generate enough pressure on either the front or rear circuit to get 'into the green' on the GS911 bleed test. Although the brakes work fine initially, as soon as I apply them whilst riding I get the fast flash and both circuits trigger a low-pressure warning.
I can only imagine my dismantling has created a leak within the system. Perhaps I needed to fit new gaskets, or at least apply some sort of sealant. There did seem to be a soft-ish seal around both pressure transducer plates, so maybe they are now leaking fluid. There is also no information on torque settings, so you just have to use what feels about right, I guess, bearing in mind the unit is aluminium!
In hindsight, perhaps I should have just tried removing and cleaning the pressure relief valves, which I think are the black-capped cylinders on the top of the unit (penultimate pic in John's last post). But at the time, I thought the unit would be full of corrosion and dirt inside.
I'm now about to give the German rebuilding company a go. ( Type AM1
). At €800 it's not cheap, and probably not worth it given the age and condition of the bike, but my alternatives are to buy a new LT, but then I'm still stuck with a ageing bike no longer manufactured, or really shell out for a GTL, which I can't afford right now. So I'm going with a rebuild, and then I'll be fastidious about servicing this bike and just hope nothing else major fails for a couple more years!
One other thought - lots of people here talk about removing the ABS unit and reverting to manual braking. For those that do this, have you told your insurers, and if so, what did they say about it? Maybe the law is different in the US, but I think over here if you had an accident and it turned out you had bypassed the ABS without telling them, it would invalidate your insurance, regardless of the cause of the accident.
For those that do want to do this, it seems RH Electronics now sell something to replace the ABS unit, so you don't have to worry about re-routing pipes etc.
Good luck Rich and everyone else with this problem.