4 C3573 Seat belt safety switch C3574 PARKING BRAKE 4.6 General Information Each drive motor contains a set of clutch pack type fric- tion discs that are spring loaded in the engaged position. The parking brake is inter locked with various safety switches. (fig. C807, C3573, C3574, C3575) The parking brake will only release when the engine is operating, the operator is seated with the seat belt fastened and the restraint bar is in the lowered position. The parking brake system requires 200 psi (13.78 bar) hydraulic pressure to release or separate the clutch packs in the drive motors. The hydraulic pressure is provided by the charge pressure relief valve in the hydrostatic tandem pump.
When the engine is operating and all safety switches are functioning and in the closed position, the hydraulic / electric solenoid brake valve (fig. C3575) will allow charge pressure to release the parking brake in the drive motors. Solenoid Brake Valve C3575 C3575 4-22