Depending on the model, these various seals are located inside the vacuum pump and between the vacuum pump and the engine block.
Tandem Fuel Vacuum Pump Seal Repair Gasket Replacement for Car
Vacuum pump seal repair kit A64623065 / 64623065 for Mercedes
Vacuum pump seal repair kit 9A111009002 for Porsche
Vacuum pump seal repair kit 057145100L for AUDI / Seat / Skoda / VW
Vacuum pump seal repair kit 057145100T for AUDI / Seat / Skoda / VW
Vacuum pump seal repair kit 94811005004 for Porsche
