2001 s320cdi high pressure fuel lift pump

[sean.ie]

seem that i need to replace this pump to back this up ; the car catches but won't tick over so i replaced the fuel filter to no avail , then dis-connected the feed out of the pump , replaced this with a handie bit of pipe of had lying about and put the open end into a bottle , on cranking only a dribble of fuel comes out , so i figure the highj pressure pump needs replacing . Now to the bones of the matter , is this easily replaced without any specific MB info?

 

[rpe2]

Before you venture down this route, have you checked injector leak off, looked for air in fuel lines, had any fault codes read?