Sterndrive bellows vulnerability

Discussion in 'Powerboats' started by erikgreen, Dec 23, 2009.

  1. CDK
    Joined: Aug 2007
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    CDK retired engineer

    If the boots are there for no reason at all, please show me a construction drawing.
     
  2. Rik
    Joined: Dec 2007
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    Rik Senior Member

    Please show me yours!

    The are there for a reason, to keep marine growth off the ball. Nothing more.

    Do you really think I am wrong? One can run the drives with no boots on them, happens all the time.
     
  3. powerabout
    Joined: Nov 2007
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    powerabout Senior Member

    On a Mercruiser if you wanted to ( with the engine removed) you could tap the hole on the inside of the transom plate and install a barbed fitting and hose in the vent hole ( mentioned above) and run it above the water line.

    The bellows extends when tilted so the air must get in.
    On a Volve its semi sealed so when tilted it pulls a vacuum..nice.....NOT
     
  4. CDK
    Joined: Aug 2007
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    CDK retired engineer

    I don't recall writing that, but now that you mentioned it.....
     

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  5. powerabout
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    powerabout Senior Member

    ahhh
    the Bravo conversion
     
  6. Rik
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    Rik Senior Member

    Ok, you are right. I know nothing about the Arneson Surface Drives.

    I apologize for my ignorance in this matter and I stand corrected. However, I must ask, if the boot's purpose is to seal water out of the drive unit under your premise, it must therefore seal oil in. Logically speaking it would have to serve a dual purpose under your claim. Therefore, I can deduce that if the boots were not present the Arneson Surface Drives would leak their lubricating oil out of them (in a matter of time of course) and damage the units both from water intrusion and the lack of oil lubrication.

    Am I following you?
     

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  7. Rik
    Joined: Dec 2007
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    Rik Senior Member

    Yes, I include the boots on the Bravo Conversions as the boats go into the salt water and there is marine life that can attach themselves to the articulating ball socket and the boot keeps this from happening. That and they make the drive look better.

    Am I correct Mr. CDK?
     
  8. CDK
    Joined: Aug 2007
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    Location: Adriatic sea

    CDK retired engineer

    Theoretically, just an O-ring or cup could keep the water out. But in a harsh environment relying on just one barrier isn't good engineering practice.
    It would be stupid not to take advantage of the two cylindrical surfaces and put a rubber boot around them.
    Arneson Industries are professionals with a good engineering reputation, so they added the $10 boot and two clamps to provide additional protection.
     
  9. powerabout
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    powerabout Senior Member

    What type of cv joint is inside the socket and how is that sealed from the sea water?
     
  10. Rik
    Joined: Dec 2007
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    Rik Senior Member

    CDK, believe me PLEASE, the boot has ZERO to do with sealing the drive from water intrusion. There is as you stated an o-ring combination in the drive that keeps the oil in and the water out. The boots are often times run with tears, rips, cuts, etc. that allow their area to fill with water and this has no affect on the intrusion of water nor the extrusion of oil.

    I build these things all week long, I use them, I service them etc., the boots are only for barnacle protection.
     
  11. Rik
    Joined: Dec 2007
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    Rik Senior Member

    An o-ring system is used to seal the drive assembly. We use a cardon joint inside the drives.
     

  12. scotch&water
    Joined: Jul 2009
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    Location: Great Falls Mt. USA

    scotch&water Junior Member

    Hi to the experts, I have a Bravo II and last year the shift boot was leaking a so anny more suggestions out there, I am interested. The Brave conversion looks interesting but my pocket is flat.
     
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