UTU brake question

Brakes now work great - will skid both tires with moderate pedal effort. However the left brake makes a loud metallic "snap" when first applied. Also sometimes it chatters under light braking effort.

I suspect it's an adjustment issue. The star wheel brake adjuster is set to it's minimum (fully retracted) adjustment and the pedal has about 1-1/2" of free play. The drums stay cool after several minutes of operation in road gear so they're not dragging. I didn't mess with the eccentric cam adjusting screw on the upper backside of the backing plate - not sure what it's purpose is. Right now it's set in it's minimum radius position.

Any tips or a procedure on how to properly adjust these brakes, or other ideas what the problem might be would be greatly appreciated!

As I understand it:

That way, the rear shoe needs to contact the drum first. then the front shoe touches, and its torque adds further pressure to the rear shoe. If reversed, the front shoe touches first, it then slams the rear shoe into contact with the drum.

Some anchor pins actually have a taper in the notch where the springs hook. If the springs are evenly matched, the front spring will be higher on the taper and have slightly more tension on it.

I can't recall if a U is this way or not.

All of this works in forward motion. They'll still clack when backing up.

I'm still puzzled by the purpose of the eccentric adjusting screw on these brakes. It appears it's to set clearance between the rear (leading) brake shoe and the drum. However I have no idea where it should be set. I presume it should be adjusted so the shoe is a close as possible to the drum without touching it with the brake released. Guess I'll experiment with it a bit and see...

Like my name? J/K

I still have to finish my album on that Epson website. I'll get back to you when I finish.

Thanks,
Trever