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Oil leak behind Air Pump Pulley

Discussion in 'Technical Q&A' started by DANCER308, Feb 3, 2010.

  1. DANCER308

    DANCER308 Formula Junior
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    Oct 24, 2009
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    KY
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    Dan
    I have been looking for an oil leak on my '79 308 GTS. I finally found where the leak was coming from. It is coming from the oil seal behind the Air pump pulley. I can see that the seal is sticking out and I can push it back in by prying it with a thin blade screw driver. Should it be that easy to move it or is it possible that the wrong oil seal was used? I know that this oil seal has a different part number than the other Cam oil seals. part # 107786; Dist oil seal # 108009; Timing belt end # 105389
     
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  3. Steve Magnusson

    Steve Magnusson Two Time F1 World Champ
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    Jan 11, 2001
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    Steve Magnusson
    #2 Steve Magnusson, Feb 3, 2010
    Last edited: Feb 3, 2010
    This (the seal OD slipping out of its bore) is a known problem. Many Mechanics intentionally take a centerpunch and put several deep dimples into the bore surfaces (at about the midplane of the seal OD surface) on both the engine block and camcover in order to "hold" onto the seal better -- next time you have the 1-4 camcover off, add 6-8 equally spaced dimples around the circumference of the bore.
     
  4. DANCER308

    DANCER308 Formula Junior
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    Oct 24, 2009
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    Steve,
    Thanks for the info, I'll do this fix next time I remove the cover. Was this a problem with the distributor seals also? I have one with a small leak, the other cover of course.

    Dan
     
  5. Steve Magnusson

    Steve Magnusson Two Time F1 World Champ
    Lifetime Rossa

    Jan 11, 2001
    20,314
    Texas
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    Steve Magnusson
    The distributor seal has to be pressed in (into a single solid piece) so the "dimple" technique isn't so appropriate (i.e., the protuding rim of the dimples, if you can add them ;), would score a trench in the seal OD sealing material during installation, and none would be present to expand into the dimple) -- for this one, it's better IMO to machine a shallow groove in the bore (i.e., no material protruding upward from the surface, but a groove that the sealing material on the OD of the seal can expand into -- like on the cam seal bores) at the seal OD midplane. If you do have trouble here, it's less of a hassle to fix so probably fewer cars have any modification done here.
     
  6. DANCER308

    DANCER308 Formula Junior
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    Oct 24, 2009
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    KY
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    Dan
    Thanks
     
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