Dual disc brakes tire used on aircraft where more braking friction is desired with lower pressures. The dual disc brake is very similar to the single disc type, except that two rotating discs, instead of one, are used. One model of this brake is shown in figure 12-32. The unit consists of a housing assembly, a center carrier assembIy, and two rotating discs. The housing assembly contains four cylinders, each of which contains a piston, a return spring, and a self-adjusting pin. Brake linings (pucks) are attached to each piston, to both sides of the center carrier, and to the housing assembly, which makes a total of 16 pucks.

Figure 12-33.-Crosssectional view of multiple disc brake.

When hydraulic pressure is applied to the pistons, the pucks are forced against the first disc, which contacts the pucks in the center carrier. This force moves the center carrier and its pucks against the second disc, forcing it in contact with the pucks in the housing. In this manner, each disc receives equal braking action on both sides as the pressure is increased. When brake pressure is released, the return springs force the pistons back to the preset clearance between the pucks and the disc. The self-adjusting feature is identical to that described for the single disc brakes. Maintenance of the dual disc brake is the same as that previously given for the single disc type.