992G Wheel Loader and 854G Wheel Dozer Braking System Parking Brake Caterpillar

Parking Brake

Illustration 1g00102882

Location of the Components for the Parking Brake

(1) Spring. (2) Plate. (3) Disc. (4) Bolt. (5) Bolt. (6) Hub. (7) Shaft. (8) Chamber. (9) Plate. (10) Pin. (11) Bearing cage. (12) Piston. (13) Plate.

The parking brake is positioned on the output transfer gear case. The parking brake is a multiple disc brake with a dry cavity which is engaged by springs (1) .

Plates (13) react against four pins (10) that are anchored in bearing cage (11). Discs (3) have splines on the inside diameter which engage with hub (6). The hub is splined to shaft (7). The shaft is driven by one of the transfer gears. The discs turn with the transfer gear shaft.

Illustration 2g00102883

Location of the Parking Brake Control Knob

(14) Parking brake control knob.

Parking brake control knob (14) is positioned on the left side of the dashboard. This knob operates the parking brake control valve.

When parking brake control knob (14) is pushed in, oil flows from the accumulators to chamber (8) behind piston (12). Piston (12), plate (9), and bolts (4) are pushed to the left when the oil fills chamber (8). Shaft (7) is able to rotate when the pressure on plates (13) and on discs (3) is released.

When parking brake control knob (14) is pulled out, the flow of oil from the accumulator stops. The flow of oil to the parking brake also stops. Oil in chamber (8) drains back to the hydraulic oil tank. Springs (1) then exert force on plate (2). Discs (3) and plates (13) are clamped together. This compression of discs (3) and plates (13) engage the parking brake.

When the pressure in the accumulators decreases below 6035 ± 515 kPa (875 ± 75 psi), the parking brake engages. The position of the control knob indicates the status of the parking brake.