Logo
FULL SITE MENU

Bravo 3 side to side prop shaft play

S

SpeeedRacer62

New member
Greetings, I have two Bravo 3's that were both leaking at the seal between the inner and outer shafts. Plus the corrosion was so bad on both bearing carriers I decided to have my trusted local shop replace these 4 items since I do not have the proper tools. After they assembled both lower units they found that both had quite a bit of side to side play (not end play, not back lash). If you have the unit mounted in a holder and grab the outer prop shaft and move it up and down, there is slack, maybe .035-.050


They're not sure if its the tapered bearings on the front and/or rear gears or something else. It has new bearing carriers so its not that. We dug thru the #28 Service manual and couldn't find an actual value for this type of play, but both mechanics there felt it was excessive.


Has anyone dealt with this type of play? I'd appreciate feedback from those that have seen this and might have a solution. These are 2004 lower cases and the serial numbers of the drives are OL470455 and 56.

drive pic.jpg
 
I guess your "Mechanics" missed the page with the specification.

See below
 

Attachments

  • Prop shaft deflection.jpg
    Prop shaft deflection.jpg
    70.7 KB · Views: 207
If the outer prop shaft and/or bearing are worn both shafts will have excess side to side play together.

Does the inner shaft have side to side play inside the outer Shaft?
 
Docksidemarineservices said:
If the outer prop shaft and/or bearing are worn both shafts will have excess side to side play together.

Does the inner shaft have side to side play inside the outer Shaft?
Click to expand...

Chris, I do not believe there's any play between the inner and outer shafts. Its the outer one that you can really see moving against the outer seal when you push/pull on the shaft.
 
SpeeedRacer62 said:
Chris, I do not believe there's any play between the inner and outer shafts. Its the outer one that you can really see moving against the outer seal when you push/pull on the shaft.
Click to expand...

Lets identify the outer and inner shaft just to be clear.

Outer shaft: The large diameter shaft for the forward propeller.
Inner Shaft: The smaller diameter shaft for the aft propeller.

If the inner has no play in the outer and the outer moves sided to side, then the outer shaft and/or bearing is worn.

The bearing would be #44 in Jack's picture above.
 
Define push/pull. Do you mean attempting to move them in line with the length or laterally perpendicular to the line of the shaft? You've used up-down and push/pull in your description but not clear in which direction. I think we are assuming you mean perpendicular to the line of the shaft.
 
Bt Doctur said:
Jack hijacked my enlarged pic too, and his keyboard must have a language glitch in it
Click to expand...

BD, I doubt that there's anything wrong with his keyboard........ it's with his attitude and inability to be polite, courteous and lack of knowing how to politely agree to disagree with other members, etc.

The adult like and right thing to do is to play nicely!



.
 
Last edited:
Docksidemarineservices said:
Lets identify the outer and inner shaft just to be clear.

Outer shaft: The large diameter shaft for the forward propeller.
Inner Shaft: The smaller diameter shaft for the aft propeller.

If the inner has no play in the outer and the outer moves sided to side, then the outer shaft and/or bearing is worn.

The bearing would be #44 in Jack's picture above.
Click to expand...


Chris, agreed on your inner and outer shaft definition. I too agree with you that it would seem that bearing #44 would be shot, however brand new bearing carriers were just installed when this was discovered. The shaft doesn't show any signs of wear to warrant this much movement. I was thinking it could be due to bearings #27 and/or #35 being worn beyond spec.
 
That amount of " side play " on precision drives sounds like too much.-----I for one would take it apart without hesitation to see what is wrong.
 
o2batsea said:
Define push/pull. Do you mean attempting to move them in line with the length or laterally perpendicular to the line of the shaft? You've used up-down and push/pull in your description but not clear in which direction. I think we are assuming you mean perpendicular to the line of the shaft.
Click to expand...

If you'll reference the picture in my original post, you'll see the direction that I am referring to. Here it is again: drive pic.jpg
 
in your first post you wrote "move it up and down" which is confusing in reference to the pic. Up and down would be in line with the shaft. I think we are all on the right track now.
 
As far as jargon goes, my goto bearing reference guide characterizes the movement in question as "radial play". There's no explicit spec for it in the service literature i have though there is a set of specs for the axial end play measurements....like racerone said, I'd be inclined to disassemble and find the worn part(s) and replace them....
 
If you are asking for end play, pulling/pushing shaft straight in and out
I believe i read .020"-.030".
 
From 8M0131886 2019 Mercury Marine Page 3E-7

Specifications
Bravo Three Gear Housing
Propeller Shaft End Play 0.254–0.660 mm (0.010–0.026 in.)
Propeller Shaft Runout
Inner propeller shaft (maximum deflection) 0.127 mm (0.005 in.)
Outer propeller shaft (maximum deflection) 0.254 mm (0.010 in.)
Gear Backlash 0.3–0.4 mm (0.012–0.016 in.)
Pinion Gear Clearance 0.635 mm (0.025 in.)
Back Driven Gear Shim Thickness 1.3 mm (0.050 in.)Shim Thickness 1.3 mm (0.050 in.) Thickness 1.3 mm (0.050 in.)
 
Last edited:
SpeeedRacer62 said:
Chris, agreed on your inner and outer shaft definition. I too agree with you that it would seem that bearing #44 would be shot, however brand new bearing carriers were just installed when this was discovered. The shaft doesn't show any signs of wear to warrant this much movement. I was thinking it could be due to bearings #27 and/or #35 being worn beyond spec.
Click to expand...

Pull it apart, there is something incorrect. There are two different outer shafts.
 
Back
Top