That yellow plunger isn't a primer, you can press that all day it does nothing.

It's a 'filter minder' shows how blocked the filter is.

Need a hand primer on the outlet of the filter to the pipe to the pump.

One of these with pipes made up to suit the filter/pipe http://www.ebay.co.uk/itm/8-MM-FUEL-...item1e7f3d4a5a

Don't crack off the pipes on a TDCI it will just introduce air.