Main fuel filter leaking on top. Am I missing something?
 

Hey, all, the 83 300SD I've been working on seems to have fuel leaking onto the top of the main screw on filter. I didn't pull the bolt when I changed the filter, but is there supposed to be a washer or seal under the top bolt? I re-tightened it, but there is still a little fuel coming from someplace and setting on top of the filter housing (head). The filter is a new one I installed, and I don't remember if was leaking when I got it or not. Can't find an exploded view of this. Does anybody have any idea what might be the cause of the leak? Thanks.

If this is the copper ring on the banjo connection above the secondary spin on filter - then you are advised to replace it. However I'd just take it apart - clean it up - and see if it will reseal. If it is bent / distorted change it. Don't over tighten the nut.

Be sure to replace the rubber "O" rings on the big banjo bolt too.

And if the banjo bolt has two o-rings, it does not need the copper washer...

Where can we get these o-rings and/or copper washers? Ideally, I'd like to get viton o-rings as I'll be running biodiesel in my 300SD.

Wouldn't that have been in the new filter box? I've got spare copper and steel rings everywhere from my oil changes. Since I didn't pull that bolt, I didn't check under it. The filter has it's own seal. Never had this problem with my 300d. (The one in question is a turbo, but I don't think that makes any difference on the fuel line. Anybody got any manual pics? I'm looking for my cd on these things. As usual, it's hiding under all of that other "real important" clutter.:o

Many auto parts stores have a whole set of drawers full of copper crush washers in various sizes. Depending on how well-stocked they are you might have to convert from metric to the next biggest inch-based size, but the exact dimensions of these washers are rarely critical.

I had the same problem with my 300 SD. Been a good while back and my memory is a bit fuzzy on particulars, but --- best I can recall the washers that came with the filter did not fit the bolt. I made one from some spare gasket material and all has been well for a long while (long enough for me to forget details). At any rate, it was easy.

Change those O rings
 

Go to your local auto parts store or Harbor Freight and get a metric selection box of O rings. Changing the O rings each time you change the fuel filter is a good thing. The copper ring goes under the head of the bolt... (Belt and suspenders)

The same goes for any place you have any O rings. Remove and replace the hard old rings with new ones. It's just a good practice.

Pete

The filter does not come with the crush washer, as this is for the old style banjo bolt.

I have used a #30 cap thread gasket I purchased from the local hardware store.

83 should not have any o-rings on the fuel filter bolt... just an aluminum crush washer.
what's the part # on the filter base? if it ends in 01 it's just got the crush washer. standard oil filter copper ones will work, the plastic ones may even work, not totally sure though.

You might want to reconsider that notion.

Copper washers are the way to go..........they seal better.

The red arrow is pointing to the "02", as you see there are two "O" rings on the banjo bolt.

A filter head with an "01" will need a crush washer. One like the one in the pic is still on my old 240, its made of a composite material.

You are the Man toomany...