Air holding tank

[new rver]

thanks for reply’s this is on air holding tank runs to block. Air is leaking out the end took off cleaned up still leaking . There’s a rubber o-ring on a plastic spring check valve. Going to replace just wondering if I should check something else. Thanks

[Ray,IN]

Confused??? Do you mean the red air line into the black connector, RH tank? That is a push-to-connect fitting. They can begin leaking for several reasons. Replacing the "O" ring and squaring the end of the tubing exactly and smoothly square often does eliminate it leaking.
The large shiny fitting is a one-way valve in addition to being a connector, same remedy applies to the line.