The original power steering pump was powered by the petrol engine so I’ve had to replace it with a 12v one. The standard option in the conversion community is to use a Vauxhall/Opel part from a Zafira.

More information over on the OpenInverter wiki.

To connect it up I am using standard oil line for the return with a banjo fitting on one end (to match the existing BMW rack) and a custom hose from Hydraulic Megastore on the other. This has a straight M16x1.5 fitting on one end, for the pump, and a banjo fitting on the other for the rack.