Having been there before myself, if you put the brake system all back together, bleed the brakes, then dry everything off around that bleeder valve, then push on the brake pedal a good bid - if there is no leakage, you might have it resolved. Brakes are one of those things, though, that I hate to have any
? about, especially on a 280SL. I think you are probably correct that if you can get the bleeder screw to seat tight against the female part of the caliper it should work. I would probably make a few calls and see if there are any used calipers available nearby just because, as I said above, I really don't like there to be any
on any part of the brakes. I'm not sure what you will be doing at Gernold's place but I will bet he has a brake caliper and if you drive there with what you have, if it were me I would replace it at his place. Shouldn't be more than 1/2 hour to R and R the caliper and bleed. I'm sure others are going to tell you don't even try it, and i would really only do it as a last resort. Maybe if you call Gernold he could overnight you a replacement caliper.