Fuel leak, 123 300D, main fuel filter bolt

Hello

My 1982 300D, 123-budy, leaks fuel at the top bolt of the main fuel filter, the big screw-on one. I am not sure it it leaked before I changed the filter, but it now does.

How much should I tighten it? Can I change or add a washer to prevent the leakage? I read somewhere about a kit to install a modified filter base part, anybody seen/used this?

Any help appreciated.

Nicolas

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1982 300D - http://members.xoom.com/nicodore/

Nicolas,

After I bought my '85 300CD-T, I discovered the same situation you describe. I fixed the problem by replacing the rubber seal ring that fits onto the bolt. The old ring had worn out and was allowing fuel to seep by. I would recommend not applying any excess torque to the bolt. The whole fuel filter assembly was designed to function properly with the proper torque on this bolt. If the bolt head is leaking fuel, even with the correct torque, the problem is elsewhere.

One other thing: Some bolts use two seal rings, some use one. You'll have to pull yours, check it out, and then acquire what you need. This worked for me.

Good luck-

Terry

Wow, thanks. This is scary: about 10 minutes between my question and your answer. Boy I love the web thing! :^)

Thanks a lot

Nicolas

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1982 300D - http://members.xoom.com/nicodore/

[Benzmac]

You should always replace all of the o-rings when servicing the fuel filter. Then tighten the filter with a suitable socket until the bolt almost stops turning but not over tight. If it is too loose it will suck air into the filter and the engine will be difficult to start.

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Benzmac:
ASE CERTIFIED MASTER AUTO TECHNICIAN
SERVICE MANAGER FOR 14 BAY FACILITY
MERCEDES SPECIALIST 8 YRS
PARTNER IN MERCEDESSHOP.COM

Hello BenzMac

I'm not sure what you mean about o-rings.

My filter is a canister that has a built-in rubber o-ring. There is a metal washer and the bolt has a rubber o-ring built into it at mid-length, which I'm not sure I can change without changing the whole bolt.

Do you mean changing the metal washer or the rubber o-ring that's on the bolt?

Thanks in advance

Nicolas

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1982 300D - http://members.xoom.com/nicodore/

Just had a chance to drop by my local MB dealer to check the parts out and it turns out that my car should have two (2) o-rings, not just one has it currently does. Sorta explains the leak...

Nicolas

[mbdoc]

Early cars came with a housing that used a crush washer & 1 o-ring. Later have 2 o-rings. Its easy to swap the housing to the later style & use the bolt w/2 o-rings.

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MERCEDES BENZ MASTER GUILD TECHNICIAN
ASE MASTER TECHNICIAN
27 YEARS M.B. TECH