777D and 777D HAA Off-Highway Truck and 776D Off-Highway Tractor Caterpillar

Illustration 1	g00622475
Dual primary air tank arrangement (S/N: AFS1-92; AGC1-1403; AGY1-199)

Dual primary air tanks are located on the hydraulic tank. The drain valve for the primary air tanks is located on the rear of the primary air tanks.

Illustration 2	g01143359
Single primary air tank arrangement (S/N: AFS93-Up; AGC1404-Up; AGY200-Up)

A single primary air tank is located on the hydraulic tank. The drain valve for the primary air tank is located on the front of the primary air tank.

Illustration 3	g01143386

The secondary air tank is located in the compartment behind the cab. The drain valve for the secondary air tank is located on the right side of the cab on the outside of the cab.

1. Open the one drain valve.

2. Check for moisture and for sediment in the air tank. Drain the moisture and the sediment from the air tank into a suitable container.

3. Close the drain valve.

4. Repeat steps 1 through 3 for the other drain valve.