Brake adjustment on the 2-33

Question to all of the 2-33 'connoiseurs' in the US:

I checked the brakes of both club 2-33. Although the linings look good,
I cannot get any decent brake action. I also noticed that the brake
lever on the wheel and the cable are almost in a straight line before
the linings contact the drum. So, no matter how hard one pulls on the
cable, the effective leverage is nearly zero. There is no slack
adjuster on the shoes as in automotive brakes. Unless I am missing
something here, the brakes cannot adjusted for wear. Our maintenance
manual does not reference anything on this subject.

1.) What is the maximum brake drum inside diameter?
2.) What is the wear limit on the linings? (No - the rivets are not
showing, in fact they are way down in the hole )

Thanks,

Uli Neumann