206 diesel fuel pipe size?

[cyclone]

hi,i have a 2002 206 1.9hdi which has been running fine until a few days ago when it would take quite a bit of cranking to get it started ,i put in a brand new battery and glow plugs and a new fuel and air filter but its still the same ,ive found that if i pump the accelerator pedal while cranking the engine it will start after about 3 or 4 attemps but as the wife drives it mostly i need to have this fixed .i was wondering if it could be a small airleak in one of the pipes ?does anyone now of the inside diametre of the pipes so as i can replace them .thanks for any help you can give me
regards cyclone