Can anyone give me a definitive answer? It's a 2006 td4
You need one of these.
Before using this tool, the inner bolt needs fully unscrewing, and the inner sprocket retainer also needs unscrewing.
Then remove the inlet manifold, and engine support bracket (support the engine weight with a protected jack under the sump), so you can access the sprocket access plug.
Once the plug is removed, you'll see the pump spindle locking nut, which needs removing.
Once the nut is removed, the sprocket locking tool outer section is then screwed into the timing cover, then the middle section is screwed in, which supports the sprocket, finally the centre bolt is centre press bolt is unscrewed in, so it just stops on the pump spindle.
Now you remove the fuel pipes, the pressure control valve plug from the pump, and the 3 pump to block securing nuts.
Once the pump is free from the block, the centre press bolt on the tool is screwed in,
which "pops" the taper, allowing the pump to be withdrawn from the block.
Refitting is the reversal of removing, but the press bolt is removed from the tool first, or it prevents the pump from engaging with the sprocket.
Once the pump is bolted back on, the whole tool is removed, and the centre nut torqued back up to the correct torque.