U joint bellows inspection Alpha one Gen one

Chuckles88

Seaman
Joined
Aug 28, 2018
Messages
51
I double checked mine last night in the dark with a flashlight. Just turn the drive and you should be able to see. That is of course if the boat is out of the water.
 

Chuckles88

Seaman
Joined
Aug 28, 2018
Messages
51
1 vent just above the gimbal bearing inside the bellows. You can see it on the transom plate from the inside just above the drive dead center
 

tfret

Chief Petty Officer
Joined
Sep 6, 2006
Messages
493
I finally made it to the lake alone today. With the *** end stuck in the water at the boat ramp, I took some photos. actually before and after putting it in the water. Appears to be a perfectly round hole at 12 o’clock directly above the drive shaft. It’s a tight space and dirty so I apologize for poor photo quality. Is this the bellow vent, confirmation that the drive shaft bellows is bad? Photos on next couple of posts, hopefully you can see it.
 
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tfret

Chief Petty Officer
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Sep 6, 2006
Messages
493
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achris

More fish than mountain goat
Joined
May 19, 2004
Messages
27,468
With the boat out of the water, did you actually look at the bellows?
 

tfret

Chief Petty Officer
Joined
Sep 6, 2006
Messages
493
Yes. Looks like new. Felt around and don’t feel anything wrong although it’s hard to really reach everywhere. But when I squeeze it I hear air exhaust somewhere. Does that make sense?
 

tfret

Chief Petty Officer
Joined
Sep 6, 2006
Messages
493
Has anyone seen this before? If that is in fact a bellows vent hole, then I guess the bellows is leaking. Just seems like I’d be getting water though the gimbal bearing and out the drive shaft hole.
 

DouglasW

Petty Officer 1st Class
Joined
Apr 20, 2018
Messages
269
Has anyone seen this before? If that is in fact a bellows vent hole, then I guess the bellows is leaking. Just seems like I’d be getting water though the gimbal bearing and out the drive shaft hole.

When I pulled my drive off for the first time for this used boat, I couldn't even see the gimbal bearing for all the grease. Also, keep in mind that normal installation procedure is to coat the driveshaft with grease before insertion. With grease all around the shaft at the outside of the bearing and grease covering the bearing, I couldn't imagine mine ever leaking much water into the boat even with a torn bellows. Could be that the vent is the only indication in some cases.
 

Lou C

Supreme Mariner
Joined
Nov 10, 2002
Messages
13,208
Ahh, never had a Merc but it almost looks like the rubber grommet for the trim sending unit is suppose to be fitted into that hole. The Cobra has a hole just like that, in about the same spot and if not fitted for sure water would come in there....
 

tfret

Chief Petty Officer
Joined
Sep 6, 2006
Messages
493
No sir, both trim switch wires exit through a separate hole up above this area. I'm fairly confident this is a vent hole for the U joint bellows and water coming from that hole is clear indication of a bellows failure. I was just hoping for one of those "oh yeah, seen that a hundred times" kinda responses before I commit to pulling it all apart. I figure I'll pull the drive off to gain better access. I should be able to see all around the bellows at that point and decide for sure if its got a problem. The U joints need to be greased anyway.
 

tfret

Chief Petty Officer
Joined
Sep 6, 2006
Messages
493
I believe this "vent" hole is actually a tell-tale hole put there to let you know when the bellows is leaking. Otherwise you would have no way of knowing until something else fails.
 

StinkinRenken85

Seaman Apprentice
Joined
Sep 17, 2018
Messages
47
I had a similar problem, put a new gasket on the trim manifold, checked the bellows and still was taking on water. Turned out I had a hole from corrosion eaten through the gimbal. Fixed it with fiberglass we'll see how long that holds up.. when i was checking my drive bellows i tried pouring some beer in it to see if it leaked out. it never did so i jacked up the trailer to get the beer back in my mug. by the way make sure you wipe the grease out of there before you try this or you may have a leak of yer own stern.
 
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