Brake Applied Brake Released Check valve Rotor (typical four places) Backup plate retainer Retracting plate Pressure plate To shuttle valve Landing gear strut Automatic adjuster Felt wiper Retracting springs (ten each) Packing Wheel bearing Wheel bearing Annulax piston Bearing retaining nut Retainer Retainer Valve stem Stator (typical three places) Compensator piston Brake pressure Return Pressure due to  retracting springs Packing Figure 13-85.  A multiple-disc brake with details of the automatic adjuster.  auxiliary stator plate with brake lining material on the side  opposite the pressure plate can also be used.  Any number of alternating rotors and stators are sandwiched  under hydraulic pressure against the backing plate of the  brake assembly when the brakes are applied. The backing  plate is a heavy steel plate bolted to the housing or torque  tube at a fixed dimension from the carrier housing. In most  cases, it has brake lining material attached to it and contacts  the last rotor in the stack.  [Figure 13-86]  Stators are flat  plates notched on the internal circumference  to be held stationary by the torque tube spines. They have  wearable brake lining material riveted or adhered to each side  to make contact with adjacent rotors. The liner is typically  constructed of numerous isolated blocks.  [Figure 13-86] The space between the liner blocks aids in the dissipation  of heat. The  composition of the lining materials vary. Steel  is often used.  13-48