How do you release gas lock on 300d?

To release a gas lock on a Mercedes-Benz 300D, first ensure the fuel tank has sufficient diesel fuel. Next, locate the fuel filter and loosen the bleed screw to allow trapped air to escape, while cranking the engine briefly. Once fuel begins to flow steadily from the bleed screw, tighten it securely. Finally, try starting the engine again; it should run smoothly if the air has been successfully purged from the system.