The brake lining and wear estimation system operates using extant vehicle sensors such as those used to implement height and stability control systems or anti-lock brake systems. This minimizes, or eliminates, the need to modify the brake units themselves. Compressed air systems used on heavy duty vehicles to support the operation of various systems, including air brakes, provide pressure monitoring features in various pneumatic circuits, which can be monitored to estimate brake lining application pressure or vehicle loading. Vehicle speed and brake actuation periods are derived from other commonly employed sensors. Data collected from the sensors is supplied to a central, programmable computer over a data bus to generate the heat and wear estimates.