The220D,

1) I backflush the primary fuel filter with gasoline then stick it back in. A spare in the trunk is a good idea, as well as a couple spare secondary filters. You have more searching and reading to do: you'll never get the air bubble out of the primary filter. You can, with the vents, get most of the air out of the secondary filter and injection pump. Let me know if you have the owner's manual - should have a photo of the injection pump. Good call in not messing with the injection pump top bolts if you aren't absolutely sure. If you have a clear injection pump return line (to top of secondary filter) then you should have very few bubbles going through it when the engine is running.

2) With your comments about additional black specks in the primary filter, I'd say it's time to pull the fuel from the tank and clean the tank. You need a new o-ring for the tank drain plug at a minimum. Before siphoning the fuel out into clean fuel jugs I would try to blow back the tank supply line from just upstream of the fuel pump, with an air compressor set at about 20psi. This should clear the tank strainer. Pull the tank drain plug after the siphon job then clean out that "dent." Put the plug and old o-ring back and put a couple gallons of gasoline in the tank. Grab a buddy and make the car do the hula: nose up and nose down a few times. Drain the gas out the bottom, then put the drain plug in with the new o-ring.

3) You're close enough to the ocean to find biocide - pure biocide without the magic potion. Check a marina or ask at a truck dealer or a parts store. It's expensive but worth every penny.

4) Before you put the fuel from the jugs into your clean tank you need to biocide and filter out the crud and water. Let the jugs sit a day or so after biociding, maybe shake the jugs once or twice. I use a furnace oil filter rigged to a 55gal barrel to do the final polishing. You do what works for you, except put contaminated fuel into your clean tank.

5) If you can fix a vacuum pump then you can change out the rubber fuel line bits at the ends of the metal fuel lines. Use bulk fuel hose - you buy it by the foot, remembering to tell the fella that it's for diesel. It's probably time and you have the opportunity with an empty fuel tank (the clean job).

6) Don't trust an automatic battery charger. The floating ball tester will tell you if you're "good to go."

Keep us posted....

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daBenz - 1970 220D