A pin for a pinned joint includes a hollow body with a first and second end caps coupled to first and second ends, respectively. The body and the end caps at least partially define a cavity within the body, wherein at least one aperture extends through the hollow body. A main piston is slidably disposed within the cavity and divides the cavity into a first chamber proximate to the first end and a second chamber proximate to the second end and fluidly isolated from an environment around the body. A lubricant is disposed within the first chamber. The main piston moves toward the first end of the body when a pressure in the second chamber is greater than a pressure of the environment. Movement of the main piston toward the first end of the body discharges lubricant through the at least one aperture.