Water and contaminants should be drained from the primary air brake supply reservoir daily unless a primary air brake supply reservoir drain valve (automatic type) is installed. Daily draining is not needed on the primary air brake supply reservoirs with the optional primary air brake supply reservoir drain valve (automatic type). The primary air brake supply reservoir drain valve (automatic type) automatically drains water and contaminants.

1. Start the engine.
2. Charge the system air pressure to the governor cut-out point.
3. Pull the cable attached to the reservoir drain valve (manual type) on the bottom of the supply reservoir.
4. After the water and contaminants stop draining, release the cable and the reservoir drain valve (manual type) will close.

1. Apply the parking brake.
2. Block the wheels.
3. Drain the primary air brake supply reservoir.

•	On primary air brake supply reservoirs with a primary air brake supply reservoir drain valve (manual type), pull the primary air brake supply reservoir drain valve cable until the primary air brake supply reservoir drain valve opens, then hold until all the air is drained.

•	On primary air brake supply reservoirs with a primary air brake supply reservoir drain valve (automatic type), push upward on the wire in the exhaust port of the primary air brake supply reservoir drain valve (automatic type) and hold until all the air is drained.

4. Open the front axle service reservoir drain valve (manual type) and drain the front axle service reservoir.
5. Open the rear axle service reservoir drain valve (manual type) and drain the rear axle service reservoirs. There is often more than 1 rear service reservoir. Make sure all rear service reservoirs are drained.