Diesel fuel leaks slowly around the fastening screw (NOT the hollow screw) at the top of the fuel filter housing on my 76 300D (115 chassis)...I've replaced the metal sealing ring several times and it still leaks...any suggestions?

What is the proper torque for the fastening screw?

Robert
76 300D 126k

Did you buy an American made filter? The German ones work better and are less susceptible to leaking. Anyway if you have tightened it up as much as you can and it leaks still, try some teflon tape at the point where the filter contacts the flared fitting and on the threads. It worked for me. Mine seeped a very very little bit and I cursed myself saying if it aint broke don't fix it. But I believe in preventive maint.

leaky main fuel filter
 

It's a German filter insert...this is NOT a spin-on filter (I think MB started using spin-ons with the 123 model)
...the leak is coming from the bolt that you tighten to hold the top of the filter housing to the bottom of the housing.

Will rubber o-rings on either side of the metal sealing ring do the trick...or is the pressure in the fuel system too much for o-rings there?

Robert