TUBE ASSEM. (26.25" Long Overall) 9S4748 - Caterpillar

Illustration 1 g00852602
Components of the Parking Brake (1) Manual release bolts (2) Warning plate (3) Bolt (six) (4) Spring (nine) (5) Plate (6) Clutch plate (six) (7) Brake disc (seven) (8) Retaining plate (9) Piston (three) (10) Chamber (11) Hub (12) Brake shaftThe parking brake is positioned on the rear of the output transfer gear case. The parking brake is a multiple disc brake with a dry cavity which is engaged by spring pressure.Clutch plates (6) are held in place by four pins that are anchored by the brake housing. Brake discs (7) have splines on the inside diameter which engage with hub (11). The hub is splined to brake shaft (12). The brake shaft is driven by one of the transfer gears. The discs turn with the brake shaft. Bolts (3) are inserted through springs (4). The bolts are fastened to plate (5).
Illustration 2 g00852603
The parking brake control knob is positioned on the left side of the dashboard. This knob operates the parking brake control valve.When the parking brake control knob is pushed in, the parking brake control valve diverts oil flow from the accumulators to chamber (10) behind piston (9). If the oil pressure is sufficient, the piston will force retaining plate (8) and bolts (3) to the left. Springs (4) will be compressed as plate (5) is pulled out by the bolts. This releases the pressure from the stack of clutch plates and brake discs. Brake shaft (12) is able to rotate when the pressure on clutch plates (6) and on brake discs (7) is released. When the parking brake control knob is pulled out, the parking brake control valve stops the flow of oil from the accumulator. Oil in chamber (10) drains back to the hydraulic oil tank. Springs (4) then exert force on plate (5) which will exert pressure on the stack of clutch plates (6) and brake discs (7). This pressure will cause the parking brake to engage.The parking brake will stay engaged until sufficient hydraulic pressure is supplied regardless of the position of the control knob.When the machine is unable to be started, there is a procedure to manually disengage the parking brake. Bolts (1) are for use in this procedure. Follow the instructions that are on warning label (2) .The parking brake is designed to hold the machine on a maximum thirty degree slope.