B737 AMM:
"Each main wheel is provided with a brake unit bolted to a flange on the axle. The brakes are multiple disc type, with stationary carrier and divided lining discs, and segmented rotating brake discs. Each brake is provided with pistons which actuate the brakes when hydraulic pressure is applied. The brakes are also provided with combination return springs and automatic adjusters. The automatic adjusters compensate for brake wear."
and A320:(d)
Do not set the parking brake ON when "BRAKES HOT" warning is shown on the upper ECAM DU.
12 twists per inch is right, it's a bit of a hangover from the old days of brake siezures. Some airlines release them on blocks and some dont.