Replace Bravo 3 bellows

Discussion in 'General Maintenance/Repair Questions' started by tony1b2000, Aug 1, 2020.

  1. tony1b2000

    tony1b2000 Member

    162
    Oct 10, 2007
    Salem MA
    350 Sundancer 2010
    496 Mag Seacore Mercruiser , Bravo III
    Once again I waited too long to get my bellows replaced. Gimbal bearing is toast.

    I read an article saying the drive should be pulled yearly and bellows changed every 2 years!
    Is anyone following this rule? If so , are you replacing the bellows (kit) yourself?

    The furthest I have done with merc tools is replace the gimbal bearing. At $1500 for a mid season haul and dealer bellow repair for 1 unit, I am wondering if this is something I can do.... Or rather do it as a 2 year PM.

    My boat does not even have exhaust bellows, just an exhaust tube...
     
  2. boatman37

    boatman37 Well-Known Member

    Jun 6, 2015
    pittsburgh
    2006 Crownline 250CR. 5.7 Merc BIII
    Previous: 1986 Sea Ray 250 Sundancer. 260 Merc Alpha 1 Gen 1
    5.7 Merc BIII
    We had our bellows done on our Alpha 1 on our 250DA and they used the Sierra bellows. This was about June 2015. We sold the boat in June 2018 and they had some little cracks starting. We bought our Crownline in August 2018 (Bravo 3) and I had the bellows replaced at the end of the season when we pulled it. Told the shop I wanted them to use Mercruiser bellows and not aftermarket. They seemed surprised but went ahead and did it. He said they were so much easier to install because they were so much more pliable. I inspected them this spring and they still looked new. And when he gave me my bill he said he said the cost difference was minimal and that he might just start using the Mercruiser stuff on everyones. Cost was about $650
     
  3. Espos4

    Espos4 Well-Known Member

    Jan 1, 2017
    Long Island NY
    2007 240 Sundeck
    350 MAG Bravo 3 W/DTS
    I pull the drive every year, mainly because of barnacles that grow inside the water inlet of the lower unit.

    2 year replacement of bellows seems excessive. My original bellows lasted 10 years (wet slipped in salt 6 months every year)
     
  4. JimT

    JimT Well-Known Member GOLD Sponsor

    Jul 7, 2009
    Charlotte, NC- LKN
    2010 330 Sundancer
    T-350mags w/BIIIs & Axius, 5.0 kw Kohler
    I just replaced the bellows on my boat after 10 years. Probably waited too long but they didn't fail. Every two years is crazy.
     
  5. BillK2632

    BillK2632 Well-Known Member GOLD Sponsor

    Jun 25, 2009
    Lake Norman, NC
    1999 185 Bowrider,
    Mercruiser 4.3, Alpha I
    My original bellows lasted 14yrs, dry stored, freshwater. It was the shift cable bellows that started leaking, U-joint bellows still looked ok, but I changed them anyhow. Do everything at once when you do them (bellows, shift cable, trim senders). I did mine myself, used Sierra parts and had no issues, 5yrs and they still are fine. Not the easiest job, but can DIY, need a few special tools. Get or build a stand for the drive - I have an Alpha so it is manageable alone, Bravo III’s are heavy, will probably need a friend to help remove/install the drive. Bellows lifespan is very dependent on where boat is used and stored - but should last a minimum of 5yrs. I pull my drive every 2yrs, replace water pump, check alignment and give everything a good inspection.
     
    Last edited: Aug 2, 2020
  6. tony1b2000

    tony1b2000 Member

    162
    Oct 10, 2007
    Salem MA
    350 Sundancer 2010
    496 Mag Seacore Mercruiser , Bravo III
    Thanks guys. I don't mind pulling the drives and check every year. What I find is that the bellows itself is the seal between the lower unit and the bell housing.
    ** Do you guys use a sealant when putting back the drive after inspection???
    Honestly, I pulled one drive last fall. Bellows loaded with water and found NO cracks in it. So where / how did the water get in?
     
  7. Espos4

    Espos4 Well-Known Member

    Jan 1, 2017
    Long Island NY
    2007 240 Sundeck
    350 MAG Bravo 3 W/DTS
    The only seal is the drive pressing against the edge of the bellows where the pressure ring is installed.
     
  8. BillK2632

    BillK2632 Well-Known Member GOLD Sponsor

    Jun 25, 2009
    Lake Norman, NC
    1999 185 Bowrider,
    Mercruiser 4.3, Alpha I
    The bellows are glued and clamped into place on the transom side The bellhousing side has a rib on the bellows that snaps them into place, then the metal ring is installed (need a special tool to do this) and the pressure of that ring holds them in place - no glue on the bell housing side. If there is water in your bellows they are leaking - either a hole or they have come loose somehow. Or the gasket where the drive mounts on the bellhousing is leaking - this should be replaced anytime the drive is removed.
     
  9. tony1b2000

    tony1b2000 Member

    162
    Oct 10, 2007
    Salem MA
    350 Sundancer 2010
    496 Mag Seacore Mercruiser , Bravo III
    There is no gasket on a Bravo 3 other than the bellows itself. Just wondering if I should put some sort of sealant on the bellows after a drive is pulled for yearly inspection? This seams like a weak joint to me...
     
  10. scoflaw

    scoflaw Well-Known Member

    Aug 10, 2011
    cape cod mass, cape coral fl
    1999 Powerquest legend 260 sx
    502 mpi Bravo 1
    I put grease on that mating surface, never had an issue. Make sure the bellows is installed on the second groove
     
    Espos4 likes this.
  11. BillK2632

    BillK2632 Well-Known Member GOLD Sponsor

    Jun 25, 2009
    Lake Norman, NC
    1999 185 Bowrider,
    Mercruiser 4.3, Alpha I
  12. tony1b2000

    tony1b2000 Member

    162
    Oct 10, 2007
    Salem MA
    350 Sundancer 2010
    496 Mag Seacore Mercruiser , Bravo III
    Got ya. That's for the water inlet, shift cable etc.. I was asking about the ujoint bellows specifically.

    Thanks for the part number. I will need that for sure
     
  13. scoflaw

    scoflaw Well-Known Member

    Aug 10, 2011
    cape cod mass, cape coral fl
    1999 Powerquest legend 260 sx
    502 mpi Bravo 1
    Nothing in that kit keeps water out of the bellows
     

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