I've been told that it's possible to pull the wiring away from the frame tube to access the point where the rubber hose from the master cylinder joins the steel tube that runs to the ABS pump.  I haven't been able to do that -- not even close.  I cut the plastic ties and pulled all the wiring harness away from the frame that I could, but I can hardly see the connection point, much less access it with a wrench.  My questions are: has anyone here actually replaced that hose?  How?  Must one remove the radiator and gain access from below the headstock? TIA

Removing the radiator would be of no help.

Undo the bracket that holds the lines down - red arrow.  Blue circle is the connection.

Thanks Drake.  May I ask what bike appears in the photo?  My 1995 K1100LT does not look like that.  I can just make out the metal bracket, but there is a rubber or plastic hood in that area that shields the brake line.  I cannot budge it and I cannot see how it is fastened down to the frame tube(s).  Very odd.  Maybe this is some bizarre modification the P.O. made to the bike. (?) I recall it came to me with a lot of "extra" wiring for the OEM alarm system.  It seems improbable that the factory would turn out something that seemingly defies accessing if brake lines should be changed out after X years.

That's a K1100RS but the metal pipe from the ABS control unit is the same part on RS and LT bikes (34322332027) so it should end at the same place.

I took advantage of our recent fine weather and wheeled the bike out into the bright afternoon light.  That made all the difference in the world!  I located and removed some ties that had previously prevented me from accessing the connection between the solid steel brake line and the flex line.  That pesky old front brake line has now been replaced.  I thereafter pulled the ABS computer/pump to send off for repair.  Honestly, that was an SOB of a job!  Made me wonder how anyone can seriously assert working on a (K1100LT) K-bike is simple. That ABS unit is tucked down in the innards in such a way that almost defies removal.  I now am hoping I will be able to reinstall it without kinking the hard lines, which need to be navigated in order to lower the ABS units back in the tray.

The metal lines are fairly flexible. You can move them around a fair amount without damaging them. (Of course I'm careful and never bend them any more than necessary.)

When doing a spline you can just strap the ABS control unit to the frame so it doesn't have to be removed.

I have received and installed the repaired ABS module in the K1100LT.  The service provided by ModuleMaster was exemplary. It was returned in less than one week.  The unit included notes from the technician that stated there was found to be a multiple faults registered from the sensors. A suspect wire was re - soldered with the speculation that it could be the cause of the faults.  That sounds plausible to me, as the gap between the rotors and sensors always checked out as within spec.  There was also rubber bits around the piston which was taken to be an indication that the brake lines (original, AFAIK) were deteriorating.  ModuleMaster gives a five-year guarantee with the rebuild/repair service.  
Okay, that all makes sense to me and, weather cooperating, I plan to bleed the brakes soon.  The lines are all new.  I plan to push the caliper pads in as far as I can, connect the MightVac to the ABS module and begin to bleed the system there, working back to the master cylinders.  What is wrong with that approach? Where am I likely to shoot myself in the foot?