The present invention relates to a multi-stage vacuum pump comprising: first and second half-shell stator components and first and second end stator components which when assembled define a plurality of pumping chambers. The half-shell components are assembled together along respective pairs of mutual engaging longitudinal faces and the end stator components are assembled at the ends of the half-shell components at respective pairs of mutual engaging end faces. A longitudinal channel is counter-sunk in at least one longitudinal face of each pair of mutual engaging longitudinal faces for receiving respective longitudinal sealing members for sealing between the half-shell components. Counter-sunk in at least one longitudinal face of each pair of mutual engaging longitudinal faces is a pocket extending transversely from the longitudinal channel for receiving sealant and allowing sealant to flow around a longitudinal sealing member received in the longitudinal channel for preventing the formation of a leakage path.