Lining wear may be checked by two methods. Before checking the brakes on any aircraft, always refer to the applicable MIM and use the method recommended by the aircraft manufacturer.

WEAR CHECK METHOD (NO. 1). Have a person in the cockpit apply the brake, and with the brake applied, measure the distance between the face of the brake disc and the brake housing, as shown in figure 12-37. If this distance has progressed to the maximum specified measurement given in the MIM, the brake should be removed and disassembled, and the lining pucks inspected for wear.

NOTE: Linings can be measured only by removing and disassembling the brake. If any puck has worn to a thickness of less than one-sixteenth inch, the entire set must be replaced. NEVER MIX NEW AND USED LININGS.

WEAR CHECK METHOD (NO. 2). -In using this method, have a person in the cockpit apply the brake. With the brake applied, check the position of the automatic adjusting pins (fig. 12-38). If any adjusting pin recedes inside the adjusting pin nut (one-sixteenth to three-eighth inch, the exact amount depending on the brake model), the brake must be removed and disassembled, and the lining thickness checked. If any

lining is worn to a thickness of one-sixteenth inch or less, the entire set of linings must be replaced. Figure 12-38 illustrates the normal position of the automatic adjusting pin (protruding out of the adjusting pin nut).