Andrew,
Concerning the dust shield on the L-14 brake assembly, ....it is my thought that it's purpose is to keep abrasives, water, etc out of the unit ....the bronze plates in my opinion would need to be protected from such in order to have a reasonable use life, as well as protecting the hydraulic acctuated piston from scratches, thus insuring it's ability in the containment of brake fluid. The Barre atoll party, are confident that the cover ( if it is such) fits on the outboard small end of the hub,....it seems reasonable to me, many examples of covers on the outboard end ( number 1 in the tireremoval procedure you mentioned)..it's like a hub cap.....keeping dirt /water out of the wheel bearings is important, as well as possibly protecting the air valve stem from damage. Why isn't it on any electra we see, I don't know , my guess is , maybe it was a big pain to deal with,....if it was designed the way the barre atoll people show it in their example, it has no air valve stem hole to add air, did it leak too much around what had to be a seal around the axle to function effectively, actually holding in more dirt than it kept out?....maybe a few other problems with it as well....( That is if it existed). Several views of the airwheel outboard hub show screw holes/ screws ....what if not holding a dust cover on is their purpose?
Jeff,
The link to the manual on the L-14 is dated 1937 ...