Adjustment of the brake pads:
To remove the brakes you first have to remove the bolt under the claw and then the excentric pin that holds the claw.
After replacing the brake pads or whatever you're intentions were you can put the claw back in place together with the excentric pin.
The book I read said that I could reposition the pin by putting chalk on the disc to see when the disc was optimal touched by the brake pads. I found this method pretty difficult and unnecessary.
The following method will do fine and is extremely simple;
To adjust the position of the pin hold down the brake handle just a bit so that the brake pads are beginning to touch the disc. Now turn the pin and keep some strength on the brake handle, when the handle can be moved the most the pin is in it's optimal position.
Finally you can put the spring and the bolt back in place.
(c) W.P.Barendsen 1999