The oil breather/dipstick allows you to check the oil level in the pump, as well as allow to allow the crankshaft to “breathe” through the vent in the breather. If the crankcase didn’t have a breather, too much pressure would inevitably build up in the crankcase and would cause oil to leak from the pump and damage its components. Make sure the vent isn’t clogged.
This item fits the following models:
3-Nailer Combo Kit w/ Accessories
3-Nailer Combo Kit
1/4" x 50 Ft Noodle Air Hose with Coupler and Plug