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1984 300D 375,000 miles 1996 e300d 266,000 miles 1983 300SD 174,000 miles Ascot Grey
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453 Posts
Discussion Starter #1
Both of my w123's are leaking from the top of the hollow bolt that holds the fuel filter on. I actually upgraded my '81 to a turbo mount, so that i could get away from a copper washer (the later ones use two rubber o-rings), but it's leaking now.
The small and large seals both appear to be flat/squared-off. Did they begin life round, and get compressed flat over time? When i order the seal from various places, i get a little o-ring that would only be suitable for the lower spot (and i don't understand its function, as it is on the other side of the outlet). What I need is the big one (top one). Anybody know where i can find it, and if it in fact will be round?
 

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1984 300D 375,000 miles 1996 e300d 266,000 miles 1983 300SD 174,000 miles Ascot Grey
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453 Posts
Discussion Starter #2
well, i just found a post that mentioned "two o-rings" AND an aluminum or copper washer. Have i been wrong the whole time? On the later filter mounts, is there actually supposed to be a washer?
 

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2013 MINI Copper S Clubman, '84 300CD-weekend car
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10,152 Posts
The pic shows the bolt I have in the SD right now.

They are "O" rings, not flat "O" rings. At least that's what I use.

I don't know the size. Perhaps you can measure the top "O" ring channel on the bolt. It's job is the same as the crush washer on your old set up.

No, about your last post. The early set up, your old one, has one rubber "O" ring and a crush washer. The later set up has two rubber "O" rings and no crush washer.

That said, what can happen is folks over the years have tightened down too much on that bolt, distorting the fuel filter head. BUT, a proper fitting top rubber "O" ring will not allow fuel to pass by it and leak out of the top.
 

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Registered
1984 300D 375,000 miles 1996 e300d 266,000 miles 1983 300SD 174,000 miles Ascot Grey
Joined
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453 Posts
Discussion Starter #4
yes- that's what i wanted to hear. Every one i have seen has just been flattened (hence the leak). Just going to buy some o-rings from the local hydraulic place, and i'll be done with it.
Also, your photo confirms that the smaller o-ring (which i have bought twice) looks kind of scrawny compared to the one on there now. The present one has been compressed to fill the groove in the bolt, and the new one is still round.
Never thought it made sense to have a washer that required X lbs of torque, torquing against a big fat soft rubber seal (spin-on filter), so i'm glad to be done with that.
Thanks!
 

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2013 MINI Copper S Clubman, '84 300CD-weekend car
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10,152 Posts
You're welcome and, you're right, no torque values, simply tighten.
 

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'83 300D
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638 Posts
Part numbers 000 997 00 48 and 003 997 58 48 at the dealership.
 
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