'87 SDL

I've searched the forum with lots of threads about air in fuel. Nothing really talking about the filter head that I could easily find.

I have a couple site glasses on my lines which were crucial to me diagnosing.

I have nice fuel going into my filter with lots of air coming out. I have tightened all banjo bolts, tightened and replaced fuel lines to the filter head and installed a new filter. Everything has been tightened beyond what I believe is reasonable. Still I have lots and lots of air in the fuel line leaving the filter.

Any thoughts? I do have steel washers on both sides of the banjo's between the bolt head, banjo, and housing. I'm wondering if this is my point, or the main filter bolt. Is there another seal to install besides the filter itself when you do a change that I may have lost? There are O-rings on the filter bolt still.

I thought about pressure testing the head, but that's not really practical. I doubt it's going to be cracked... I'd have thought I would have found leaking diesel at some point.

HELP!

Bill

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'87 300SDL, intensely modified Greasecar setup, with nickle plated heat exchanger, 3 valve setup, 312,000 miles
'95 Suburban diesel, Greasecar basics, 16 plate heat exchanger, mercedes fuel lines, Racor filter
'85 Renault Alliance converted full electric vehicle