 | |
| Illustration 1 | g01166247 |
The parking brakes are spring applied and hydraulically released. These wet brakes are engaged through the compression of a series of disks and plates. The disks are splined to the brake coupling. The plates are splined to the housing. The brake plates and disks are lubricated by the splashing of the hydraulic oil on the components.
Brakes Engaged
Oil from the auxiliary hydraulic pump is used in order to release the parking brakes. When the brakes are engaged, the brake solenoid opens the brake passage to the hydraulic tank. The brake springs move the brake piston against the discs and plates. This action compresses the disks and plates so the brake coupling cannot rotate.
Brakes Released
When the brakes are released, auxiliary pressure is directed into the brake piston chamber. Auxiliary pressure acts against the brake piston. This action works against the brake springs. The auxiliary pressure overcomes the spring force, and the brake piston moves. This movement releases the compressive force on the disks and on the plates.