I've new viton o-rings except for the one on the banjo bolt that feeds the pump overflow back to the top of the filter housing.

My leak though is at the top connection that feeds the return flow of the injectors, the injection pump, and trapped air back to the fuel tank.

It was leaking pretty good before I changed to o-ring and still leaks about the same after changing the o-ring twice.

I tried to snug up the hose by making sure the top retaining plate was putting good pressure on the three hoses it holds in place. Also tried to hold it up in position with cable ties. Still kept leaking.

Guess I'll have to try a new hose next but seems the o-ring replacement should have kept it from leaking.

Questions, Has anyone tapped threads into the filter housing so brass fittings can be screwed in?

Is there another old style housing that might have metal hose fittings?

O-rings are easy to work with but I don't like what seems to be one of the main problem areas for the future. Seems metal fittings and good quality hose clamps would be better long term.

Attached Thumbnails

 

This guy did to enable him to fit a twin tank veg kit
Jake's 99 e300d Vegoil Conversion: Rerouting the fuel plumbing, new O-rings

Thanks Mrkybenz

That method still keeps the o-rings, I was thinking of the fuel filter housing being made out of aluminum. It could possibly be tapped and brass fittings put in. Thought there might be an older version with metal fittings that would work.

I'm thinking of, just ordered one, installing the old style in-line filter to eliminate the existing prefilter plumbing.

My routing would bring the fuel line to behind the headlight assembly through the old style prefilter and direct to the fuel pump using that method you pointed me to. This would also eliminate the fuel heater, but Texas is hot enough that shouldn't matter.

Doing this would eliminate 3 of the o-ring connections, plus the prefilter would be visible for checking.

If I can find/modify a filter housing to have metal fittings that would just leave the fuel pump inlet and outlet with o-rings, plus the tiny o-ring on the banjo overflow bolt fitting. I trust good hoses, fittings, and clamps much more than o-rings. I want to travel quite a bit this year using the Mercedes, don't want to have preventable problems if I can avoid it.

Found my fuel leak source today, there is a very tiny crack in the black plastic, visible by putting a little pressure on the fitting.

I have no idea if it'll fit or not on a 606, but the 603 and 617 style filter bracket is aluminum and uses Banjo bolts with aluminum crush washers for seals.

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The guys threading the filter housing to fit barbed fittings, the other lines remain fitted with o rings though.