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Fuel drain plug leak

Discussion in '308/328' started by Irishman, Oct 27, 2019.

  1. Rifledriver

    Rifledriver Two Time F1 World Champ

    Apr 29, 2004
    26,949
    Austin TX
    Full Name:
    Brian Crall
    Generally the plugs with copper washers are tightened until you can just feel the copper yield and crush slightly. That is why it is so important to replace the crush washer every time. Be careful on those. Because they are bored out and hollow I have seen the fuel drain plugs fracture and break the head off with the expected consequences. Happened to me recently removing one.
     
  2. mike32

    mike32 F1 Rookie

    May 13, 2016
    2,622
    Uk
    A lot to be said to replace copper sealing washers with Dowty Seal rings.
     
  3. Rifledriver

    Rifledriver Two Time F1 World Champ

    Apr 29, 2004
    26,949
    Austin TX
    Full Name:
    Brian Crall
    Why? Nothing to fix. In 40 + years I have not once had a problem with those leaking.
     
  4. mike32

    mike32 F1 Rookie

    May 13, 2016
    2,622
    Uk
    You can remember back 40 years, you r in a better state than me in your old age- i remember this xmas but thats about it.
     
    Milkshaker0007 likes this.
  5. johnk...

    johnk... F1 Veteran
    Owner

    Jun 11, 2004
    7,915
    New England/FL

    Love it. This is so Ferrari Chat. One guy has a problem and the fix is to change the way it's been done since the creation of the universe. :rolleyes:
     
    Rifledriver likes this.
  6. conan

    conan Formula Junior

    Nov 13, 2011
    305
    Anneal the old washer and sand it with 600 paper or similar until it is flat enough.

    In case one suspect damaged surfaces, it is easy to sand also the surfaces until flat. Just use a marker pen on the damaged surface, tighten the plug just a bit and see if the marking has been evenly worn off. Sand a bit more on the high spots (worn off places) until perfect!
     
  7. ZOOOOMZ

    ZOOOOMZ Karting

    Aug 14, 2013
    235
    Austin, Texas, USA
    Full Name:
    Tim Cronin
    Adding my 2 cents' worth, in case it helps anyone... I had this problem on my 328 after installing those sexy silicone hoses (sleeves) on the crossover pipe. I'd removed the dry plug to drain the fuel, then used a fresh aluminum sealing ring, from a well-known yellow-box supplier. Cleaned the plug and sealing surface of the fitting, then installed the new sealing ring without thinking twice. Tightened until I could feel slight deformation (or convinced myself that I felt it), filled with fuel and took the car off the lift.... Next day, I smelled fuel in the garage, and found a wet spot on the cardboard underlay, right below the drain plug.... figured I hadn't tightened it quite enough, and gave it another grunt on the wrench.... Days later, same thing. I continued like this for a month, before I finally put the car back on the lift and pulled the plug, to find that the sealing ring was defective from the start! Replaced it with another fresh one from the same yellow-box supplier, and I've been leak-free ever since (~3 years or so)...
    In the pics below, you can see the defective ring. Never noticed that "cut" when I installed it (at about 2 o'clock in the pic) but it came from the supplier that way, and I know now that it never would have sealed. (had I noticed it, I might have used it anyway, thinking the soft aluminum would deform enough to seal anyway.) Note: You can see the grinding marks from when the washer was surfaced in manufacture, and note that it's aluminum, not copper.
    My takeaway is to put on your 10X magnifier and inspect all sealing rings (even brand new ones) closely before installing them. (aluminum, copper, all of them, for fuel, oil, or any other application).... I'm sure this is a very rare instance, but it would have saved me lots of trouble if I'd just done that the first time. A visual 10X inspection takes less than a minute, and can save annoying rework and comebacks.
     

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  8. Rifledriver

    Rifledriver Two Time F1 World Champ

    Apr 29, 2004
    26,949
    Austin TX
    Full Name:
    Brian Crall
    All this so you can save 50 cents on a new seal? Really?
     
  9. conan

    conan Formula Junior

    Nov 13, 2011
    305
    I have seen it a few times, and just placing some sandpaper on the bench and grinding a few turns on the washer quickly reveals imperfections.
     
  10. thorn

    thorn F1 Rookie
    Silver Subscribed

    Aug 7, 2012
    2,569
    Tallahassee, FL
    I had no idea I had bucket of veritable recyclable gold.... $200 takes them all (annealing and sandpaper not included.)
    Image Unavailable, Please Login
     
  11. ZOOOOMZ

    ZOOOOMZ Karting

    Aug 14, 2013
    235
    Austin, Texas, USA
    Full Name:
    Tim Cronin
    Wow, thorn, some of those are really mangled.... do you sometimes have to pry them off or something?
     
  12. thorn

    thorn F1 Rookie
    Silver Subscribed

    Aug 7, 2012
    2,569
    Tallahassee, FL
    Yep. Put the bolt/washer in a bench vise, then use a ratchet to unscrew the bolt from the washer.
     
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  13. mike32

    mike32 F1 Rookie

    May 13, 2016
    2,622
    Uk
    The handy thing about a dowty seal is that the washer is alloy and the rubber seal protrudes each side of the washer. You might call them something different your side of the pond, but used on hydraulic fittings as seals.
     
  14. Rifledriver

    Rifledriver Two Time F1 World Champ

    Apr 29, 2004
    26,949
    Austin TX
    Full Name:
    Brian Crall
    There are much easier, faster ways.
     
  15. Martin308GTB

    Martin308GTB F1 Rookie
    Silver Subscribed

    Jan 22, 2003
    3,981
    SW-Germany
    Full Name:
    Martin N.
    And then we have to rely on the service life of the rubber material exposed to modern aggressive fuel. Hydraulic oils are much less problematic. Another can-o-worms.

    I have found my individual solution how to handle that fuel drain plug. I keep my hands off it. But not so much because of the copper washer, but simply because I have not much confidence regarding the welding of the threaded boss or the surrounding wall thickness of the pipe when applying the necessary torque to break the plug free.
    I tilted the car to the left, when emptying the tanks via the pump hose connection prior to my crossover hoses job. So just a very small amount of fuel remained inside the crossover pipe.

    Best from Germany
    Martin
     
  16. Rifledriver

    Rifledriver Two Time F1 World Champ

    Apr 29, 2004
    26,949
    Austin TX
    Full Name:
    Brian Crall
    I remove them all the time in servicing the cars. Never seen an issue with the welds. Just need to use common sense in removing and reinstalling.
     
  17. Irishman

    Irishman F1 Rookie

    Oct 13, 2005
    3,465
    Raleigh
    Full Name:
    Kevin
    I should have posted here asking for advice. I found it very challenging figuring out how to get that pipe out of the car. Maybe the '78 is special in that regard.
     
  18. Rifledriver

    Rifledriver Two Time F1 World Champ

    Apr 29, 2004
    26,949
    Austin TX
    Full Name:
    Brian Crall
    There really isn't a simple way to get it out. Typically I leave the pipe in place when replacing hoses etc.
     
  19. conan

    conan Formula Junior

    Nov 13, 2011
    305

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