1. If necessary, disconnect the high tension wires and the crankcase ventilation hose to access the vacuum pump, which is located on the left side of the cylinder head.
2. Loosen the connecting bolt and disconnect the vacuum hose from the pump. Remove the sealing gaskets.
3. Unscrew the two nuts and remove the vacuum pump from the cylinder head. Remove the seal.
4. Remove the plunger from the vacuum pump.
5. Clean the contact surfaces of the pump and cylinder head.
6. Installation is carried out in the reverse order. Use a new seal and connection washers.
[The original article is posted on the resource: AudiManual]