Here is my post from another thread, just in case you missed it:
I started driving my Darrin and found the brakes difficult to stop. I didn't arc them at the time since there worked fine 6 years ago when I was driving it before the restoration, what a mistake!!
I arced the fronts and what a difference. Pictures tell the story!!
pic 1 arcing machine, this is what they look like! You must first use a micrometer on the Drum for the actual diameter, then set the machine up for that diameter. Then you slowly arc the shoes till they match the drums - 100% contact!!!
pic 2 first pass shows a high spot in the middle.
pic 3 shows only about 1/4 of the shoe making contact.
pic 4 after taking a few more thousands off, we are getting close!
pic 5 100% contact. They will act like you have power brakes!!!
The machines are hard to find, however, they work great.
Also, this is a reply from someone who couldn't find an arcing machine
Yep, arcing the shoes makes a big difference. I do my own with coarse sandpaper on the inside of the drum. Carefully 'sand' the shoe material back and forth, keeping the shoe flat against the drum & sandpaper. I use a spray bottle of water with a little dish soap added to keep the dust contained. When you are done, clean everything with brake cleaner onto paper towel or shop towel and dispose of the towel and debris.
I've considered gluing the sandpaper to the drum (temporarily of course
) to make the process a little easier, but I haven't really had an issue with the sandpaper staying put especially when wet. Hold the paper with one hand to keep it from sliding, and use the other hand for the shoe.