The jack includes a manual reservoir vent valve. This valve must be opened when the jack is being operated. If the vent valve is closed when lowering the jack, the reservoir gasket seal could be damaged due to internal pressure caused by fluid returning from the cylinder to the reservoir. The reservoir gasket must be coated with an approved non-hardening sealant when performing a repair or overhaul. Refer to the jack Owner’s Manual for operating procedures, repair procedures and spare parts.