They are connected through a linkage to an equalizer lever (fig. 7-27) rod assembly, and cables connected to the parking/emergency brake mechanism within the drums/discs (fig. 7-26) at the rear wheels.

Several types of parking/emergency brakes are manufactured for construction equipment, such as the external contracting, the drum, and the disc types (fig. 7-28). These are drive line brakes common to heavy construction equipment. They are usually mounted on the output shaft of the transmission or transfer case directly in the drive line.

Figure 7-27. - Equalizer linkage.

Theoretically, this type of system is preferred for heavy equipment because the braking force is multiplied through the drive line by the final drive ratio. Also, braking action is equalized perfectly through the differential. There are some drawbacks to this system, however - severe strain is placed on the transmission system, and also the vehicle may move when being lifted since the differential is not locked out.

Figure 7-28. - Examples of drive line parking/emergency brakes, transmission mounted.