Air in lines 1981, 300sd

Car wont start. New strainer, clean tank, new bosch primer pump and assembly, new plasic lines, new feul filters, new glow plugs and all are working, did diesel purge (2 cans). Car runs on diesel purge setup. I'm lost so I took car to foreign car mech (local benz expert) and he tried an electric pump and....ran for one day then died again. He's saying air is getting in lines...but we both have no idea...please help!!!

Forums

Chassis Model Number