A well drilling head comprises a well drilling head housing, a bearing assembly, a first lubricant manifold and a second lubricant manifold. The well drilling head housing has a sidewall structure defining a central bore. The bearing assembly is configured for being removably seated within the well drilling head housing and for having a stripper rubber assembly attached to a lower end portion thereof. The bearing assembly includes a plurality of bearings and a bearing lubricant flow path configured for allowing bearing lubricant to be circulated through the bearings. The first lubricant manifold has a bearing lubricant passage coupled to the first end portion of the bearing lubricant flow path. The second lubricant manifold has a bearing lubricant passage coupled to a second end portion of the bearing lubricant flow path.