Pretty Girl Explains How (not) to do Drum Brakes

Biggest mistakes with drum brakes, other than "the usual" meaning improper re-assembly, etc
1...Trying to use worn drums that have not been turned or that are turned too far oversize. When drums wear, they become irregular, tapered (belled) or bowed internally, and any way they wear this means they do not fit the new shoes contour, and therefore lining contact area is reduced--and so the shoes are in effect "smaller" because of less contact. If this condition is different from left to right side of the vehicle, they will pull
2...Having drums turned, but NOT shimming or "arcing" the shoes to match. Same as (1) above, now the shoes are a smaller effective diameter than the drums, and you have less contact. Worse, the contact of the lining that is now left--is trying to do "all the work" and becomes overheated, and glazed, and after that things are even worse

3...Not getting the system parts physically clean enough, which results in shoes sticking, dragging, not seating correctly on retract, maybe the parking brake does not release (or engage!!). So then you have dragging, noise, etc. Also included is getting your greasy fingers all over the new shoe lining, which causes various pulling and grabbing problems.

I mentioned nothing of hydraulics, because those mistakes apply to disk or drum systems