It sounds like you need to change your fuel supplier.
After you blow the line out you will need to bleed the line. Depending on how much fuel is in it, gravity often does most of it. Facing the car down hill also helps. Something like a mighty vac can be useful.
I gently blow a little air down the return line with the filler cap back on, even though most of the air will be leaking out the tank breather ( you will hear it) it often gives just enough pressure to bring the fuel up the supply line, so I can then reconnect it to the primary filter.
Or you can just prime it with the primer pump.
Good Luck !!

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Grumpy Old Diesel Owners Club group

I no longer question authority, I annoy authority. More effect, less effort....

1967 230-6 auto parts car. rust bucket.
1980 300D now parts car 800k miles
1984 300D 500k miles
1987 250td 160k miles English import
2001 jeep turbo diesel 130k miles
1998 jeep tdi ~ followed me home. Needs a turbo.
1968 Ford F750 truck. 6-354 diesel conversion.
Other toys ~J.D.,Cat & GM ~ mainly earth moving