[Marco Tahtaras]

Originally Posted by Will N

Marco, Not sure I understand your point. If you center the shoes around the axle, and the drum braking surface is by design centered on the axle, how does it matter if the drum is oversized?

It's tough to describe all the variables with the geometry. In simple terms using a front brake as an example. Lets say you center the shoes at .040" smaller than the drum. What is the first thing you do after installing the drum? You go to the top of the backing plate and crank in the adjusting wedge until you get a "slight drag" on the brake. What you have done is expanded the TOPS of the shoes a bit over .020" while the lower end or "toe" of the shoes remain fixed on the tracks. You have now enlarged the circle UPWARD which raises the center of that circle. That means if you've bent the roller tracks, or better yet used custom roller pins to set the height or vertical center of the shoes you've just undone that work.

Now it IS possible to get close with a cheap centering tool as long as it holds it's setting. Start by installing the brake drum completely. Next, adjust the wedge until you have a very slight drag. Remove the drum and adjust the centering tool to the highest point on the shoes where drum contact occurred. Ideally that would be the heal of both shoes but more likely it will be the heel of JUST ONE.