Bravo 3 Gear Lube Reservoir Question

Discussion in 'Sport Boats' started by mosher0330, Aug 22, 2021.

  1. mosher0330

    mosher0330 New Member

    14
    May 23, 2021
    2003 Sea Ray 270 SunDeck
    6.2L
    I have a 2003 SunDeck 270 with a 6.2L and Bravo III. I changed the stern drive gear lube at the beginning of the season, filling from bottom up and then filling the reservoir under the engine hatch. I used high performance MerCruiser gear lube. A few times since changing it I’ve had to add an inch or two of gear lube into the reservoir. Today I noticed the reservoir was all the way down to the “add” line. Is this normal? I see no lube leaking inside the engine compartment, nor is anything leaking from the stern drive, or in the water (which would not noticeable due to oil residue in the water). Any advice would be helpful.
     
  2. Lazy Daze

    Lazy Daze Well-Known Member TECHNICAL Contributor GOLD Sponsor

    Apr 21, 2009
    PA
    Various
    Various
    Air bubbles. A better way to fill is to keep filling until the lube starts to show up in the bottle. However, it's a good idea to clean the bottle out, first. Over time, the lube gets thick and gunky inside the reservoir bottle. You likely had an entire tube/hose full of air.
     
  3. paulswagelock

    paulswagelock Well-Known Member

    Oct 25, 2010
    pa
    2018 SDX 270 OB 300 Verado
    Verado 300
    ^^^^^^ this. You could have dropping lube levels an entire season from trapped air. Use a turkey baster or Mityvac type extractor to empty the reservoir, don’t let the oxidized lube drain into the lower unit.
     
  4. mosher0330

    mosher0330 New Member

    14
    May 23, 2021
    2003 Sea Ray 270 SunDeck
    6.2L
    Appreciate the feedback, the answers seem to point at air bubbles. Question, given there are air bubbles, does that mean my drive unit is not full of lube? I put a little more than 2 quarts in the unit filling from the bottom. Or, does it just mean there is air between the stern and the reservoir bottle?
     
  5. Lazy Daze

    Lazy Daze Well-Known Member TECHNICAL Contributor GOLD Sponsor

    Apr 21, 2009
    PA
    Various
    Various
    The air bubbles would have worked their way out of the gear casing by now (if they were ever there) -- after all, gravity still works ;) A full change uses about 3 quarts.
     
  6. Spark600

    Spark600 Well-Known Member

    398
    Dec 28, 2013
    South Shore Long Island NY
    2015 Sundancer 410
    Onan Generator
    Mercury dinghy
    Cummins QSB HO 380 HP
    Zeus Pods
    Have the drive pressure tested, you could have a possible leak in one of the seals.
    Check in the bellows for oil.
     
  7. Wanderer 290

    Wanderer 290 Well-Known Member

    756
    Jul 1, 2019
    Traverse City
    01 sea ray 290 sundancer
    Twin 5.7 b3’s
    2 qts. Is not enough lube to completely fill an empty bravo. Specs call for 3 qts. If the unit has the reservoir.
    When I service my units I use every bit of 3 qts.
    So, with only putting in 2qts. there are definitely air bubbles present.
     
    Espos4 likes this.
  8. Espos4

    Espos4 Well-Known Member

    Jan 1, 2017
    Long Island NY
    2007 240 Sundeck
    350 MAG Bravo 3 W/DTS
    Same here. I’m a good way Into my 3rd quart when the reservoir starts to fill, Although I don’t remember exactly how much of the 3rd quart I use, I always have 3 on hand when changing the gear lube. And even then, I’ll have to top off 1-2 times after the first couple of runs of the season.
     
    Wanderer 290 likes this.
  9. mosher0330

    mosher0330 New Member

    14
    May 23, 2021
    2003 Sea Ray 270 SunDeck
    6.2L
    Would I be correct in stating that since I filled from the bottom up until the oil came out of the vent hole, that my stern drive itself was full of lubricant, however the line between the stern and reservoir bottle had air pockets? I put about 2.5 quarts in it before the lube came out of the vent hole.
     
  10. mosher0330

    mosher0330 New Member

    14
    May 23, 2021
    2003 Sea Ray 270 SunDeck
    6.2L
  11. scoflaw

    scoflaw Well-Known Member

    Aug 10, 2011
    cape cod mass, cape coral fl
    1999 Powerquest legend 260 sx 502 mag
    2005 Baja 242 islander 496
    502 mpi Bravo 1
    496 mag B1
    My B1 only takes a little over 2, I wouldn't sweat that. Just keep topping off after runs, it will work its way out.
     
  12. Texomakid

    Texomakid Member

    25
    Jun 11, 2021
    2005 280 Sundancer
    Twin 5.0 w/Bravo III Drives
    I just did this a few months back on both of my BIII drives. I clamped off the hose below the reservoir mounted on the front of the motor with a set of vice grips, Drained the drive and then filled from the bottom until it ran out of the top port. I then reinstalled the screw to the top port, then I removed the filler hose and reinstalled the screw to the bottom port. Removed the vice grips I had on the hose coming from the reservoir and topped off the reservoir.

    Only took a little more than 2 quarts to fill each drive and a second top off after a few hours of running them. Haven't added any to the reservoir since. After a couple of top offs if the reservoir isn't staying full I'd say you may have a leak somewhere?
     
  13. Texomakid

    Texomakid Member

    25
    Jun 11, 2021
    2005 280 Sundancer
    Twin 5.0 w/Bravo III Drives

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