Here are a couple of pics to facilitate the
discussion:

http://user.it.uu.se/~embe8573/bike/brake/

I've heard that

1) the long spring pin should be in the
middle boss hole

2) the pads/shoes/blocks should be slightly
pointing inward on the rim on the front
end

3) the arms should be vertical

4) between the cable anchor bolt/cable
clamp and the noodle/guide should be
39mm of cable

Is there a trick/algorithm to achieve all this?
I have put together several but 1, 2, 3 don't
come automatically for me

--
underground experts united
http://user.it.uu.se/~embe8573