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One hot wheel-end relative to others indicates that brake is doing more work. A maladjusted automatic slack adjuster (ASA) or a seized cam/roller can cause excessive stroke, reducing mechanical advantage and keeping the shoe in contact longer, generating heat. Ironically, an out-of-adjustment ASA can either under-apply (long stroke, reduced torque) or cause drag depending on geometry and return spring condition. Confirm stroke length using the brake stroke gauge, compare to maximum allowable; if excessive, follow OEM procedure to determine whether the adjuster is defective or foundation components are worn (bushings, cam, rollers). Air dryer or governor issues (B, C) affect system-wide moisture or pressure but would not isolate heat to one wheel-end. An ABS sensor fault (D) may reduce modulation control during skids, but on a steady descent with no ABS activation, temperature concentration at one wheel points to mechanical imbalance. ASE T4 emphasizes measuring applied stroke, checking S-cam bushings, verifying adjuster operation, and correcting drag to prevent fade and lining damage.