Water in Bellows?

Discussion in 'General Maintenance/Repair Questions' started by tony1b2000, Nov 10, 2019.

  1. tony1b2000

    tony1b2000 Member

    145
    Oct 10, 2007
    Salem MA
    350 Sundancer 2010
    496 Mag Seacore Mercruiser , Bravo III
    Hello all,

    Had a bit of a grinding sound the last few weeks on the starboard engine. Had a feeling it was a bad gimbal bearing. Was ready to replace today and pulled the drive. Noticed the bellows was full of muddy like liquid. So now I know why the gimbal bearing went bad....
    Also, while pulling the boat out of the water, lots of corrosion all around the drive. Had to replace all the trim cylinders.
    So how did the water get in there? The bellows look ok, no cracking that I can see.
    Last spring, I had the marina pull both drives and they saw NO water in the bellows but the u joints were rusted. Did they not seal the drive correctly?

    What I really dont understand is there is NO gasket between the drive and the bellows. So how does it keep the water out and not seeping in through the drive and the bell housing???
    Can water be coming from the drive???
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  2. Espos4

    Espos4 Well-Known Member

    Jan 1, 2017
    Long Island NY
    2007 240 Sundeck
    350 MAG Bravo 3 W/DTS
    No gasket for the B3.

    The seal is made when the drive is pushed up against the outer edge of the bellows. They do dry out over time and may not seal as well as they age.

    I found a small amount of water in mine 2 years ago. Couldn’t find any rips or tears in the bellows. I installed a new mercruiser bellows and last year, found no water inside. I’ll be removing the drive in the next week or so and we’ll see how well it held up this year.
     
  3. RollerCoastr

    RollerCoastr Well-Known Member

    Nov 15, 2007
    Cedar Point, OH / Miami, FL / MacRay Harbor, MI
    1997 400DA
    340HP 7.4 Mercruiser Bluewaters
    Garmin 741, 742, 8212, 24HD, Intellian I2
    1999 280BR
    Twin 250HP Merc 350 Alpha Ones
    Do you mean bell housing? There are gaskets for bell housings...
     
  4. scoflaw

    scoflaw Well-Known Member

    Aug 10, 2011
    cape cod mass, cape coral fl
    1999 Powerquest legend 260 sx
    502 mpi Bravo 1
    Like Espos said, the drive makes contact with the bellows. I put a layer of grease on the contact area.
     
  5. DWABoat

    DWABoat Member

    103
    Aug 13, 2019
    S Louisiana
    2001 280 Sundancer
    1989 220CC Cuddy Cabin
    Twin 4.3 w/Alpha Ones
    5.7 Mercruiser Alpha One
    On the Alphas there is a rubber ring between the steel bellows ring and driveshaft housing. The rubber ring pushes/seals when the bolts are tightened. In addition, I load the grease there as well.
    Do the Bravos have the same sealing technique?
     
  6. tony1b2000

    tony1b2000 Member

    145
    Oct 10, 2007
    Salem MA
    350 Sundancer 2010
    496 Mag Seacore Mercruiser , Bravo III
    Thanks Guys. I like the idea of using grease as the seal may dry out over time. Wondering if a certain type of grease is better than other so it wont hurt, deteriorate the rubber ...
     
  7. Espos4

    Espos4 Well-Known Member

    Jan 1, 2017
    Long Island NY
    2007 240 Sundeck
    350 MAG Bravo 3 W/DTS
    I use Yamalube grease for everything.
     
  8. Espos4

    Espos4 Well-Known Member

    Jan 1, 2017
    Long Island NY
    2007 240 Sundeck
    350 MAG Bravo 3 W/DTS
    88A0BE37-8C98-49BA-BDE2-590B7514AEE8.png
     
  9. Thornton69

    Thornton69 Active Member

    455
    Sep 15, 2014
    Northern BC
    1981 245 SDC
    1984 18' Valco sled
    5.7 260 Merc/ Bravo 2
    Evanrude 115/80 jet
    Is that amount of corrosion considered normal in your area for a 9 year old outdrive?
     
  10. tony1b2000

    tony1b2000 Member

    145
    Oct 10, 2007
    Salem MA
    350 Sundancer 2010
    496 Mag Seacore Mercruiser , Bravo III
    No, this is my first year seeing all my zincs gone and my skegs badly pitted when I hauled. 2 trim cylinders destroyed. The dock I am at is only 5 years old with gfi protection. However, there are a few different boats near me this year. Some had cords in the water. Next year, i plan on a mid season haul out to replace all anodes
     
  11. Thornton69

    Thornton69 Active Member

    455
    Sep 15, 2014
    Northern BC
    1981 245 SDC
    1984 18' Valco sled
    5.7 260 Merc/ Bravo 2
    Evanrude 115/80 jet
    That's horrible. Do you have functioning Mercathode systems on your drives? When replacing the bearing, have a good look at the opposite end of the main bellow. A bad clamp or corrosion on the gimbal housing can be another point of entry for that water.
     

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