DIY Outdrive Service Problems

mx77racer

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Oct 2, 2017
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I could use some in help solving the problem I've created and I'd appreciate any input.

First, the background. I purchased a 94 Maxum 2700 that was in average condition back in May of this year. It was in good working condition during the survey, but I knew I wanted to make sure it was capable and seaworthy to reach dive sites off the east coast. There was not much history available on the boat. I consider myself good with tools as I've done a lot of different mechanical projects in the past.

Now to the story. I've replaced a lot of the engine parts and converted it to a closed cooling system. I used it a few times over the summer and eventually discovered it was leaking a small amount of water from the transom. Not much for a day out, but nothing you'd want to overnight on. I decided to replace all the bellows, gimbal bearing, water hose, trim senders, and shift cable on the Bravo 2 outdrive. I did not use OEM parts and maybe that's a big part of my problem. I have a service manual and I thought I followed the directions correctly. When I finished and put the boat into the water it was leaking way worse than before I started. The job didn't sound that difficult and I felt like I did everything right, but clearly I screwed the pooch on this one. Afterwards, when I pulled the lower unit, there was water in the u-joint bellow and the exhaust bellow. I'm not sure yet about the shift cable bellow. I used bellows adhesive and followed the manual. I cleaned and removed all corrosion before reassembly. I'm completely frustrated with how I messed this up, as I'm usually good at fixing things. I am curious as to why there is no gasket between the drive housing and the gimbal housing. Other than the orings around the water hose, shift cable, and oil line, there is nothing to keep water out. What seals the water from entering the u-joint bellow? My though was that the drive shaft housing is pressed (when tightened) into the end of u-joint bellow and that is what seals it.

Any insight into what I did or didn't do is much appreciated. Thanks
 

Bt Doctur

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Who`s manual? water in the exaust bellow is normal. Did you seat the aluminum ring correctly?
 

mx77racer

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I'm fairly certain it's one of the Seloc Service Manuals for the appropriate year. I seated the ring using the proper tool and it look to be on good.
 

tpenfield

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I am betting my $5 on the bellows was only 1 ridge in on the bell housing, so the outdrive could not make a seal.

mx77 . . . . the o-rings are fine as they have nothing to do with the bellows sealing. They only seal the oil line the shift cable interface and the water intake.
 

mx77racer

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The bellow was in the correct ridge. I confirmed that when I disassembled. I've read other posts that indicated there is a top label on the bellow but I didn't see one.
 

mx77racer

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I think I've determined what the problem is. I might be sure after I get the OEM replacement u-joint bellow which I just ordered. As I previously stated, I didn't use all OEM parts and the bellows kit I used was SEI. Upon taking measurements I determined that the metal piece on the drive housing that fits inside the gimbal housing and presses up against the edge of the bellow is exactly 2 inches long. The measurement from the edge of the gimbal housing inside to the edge of the bellow in the correct placement was also exactly 2 inches. I took this measurement after I'd already removed the sleeve, but I expect the sleeve installed might make that distance a tad more. Since a water tight seal depends upon the drive housing being pressed into the edge of the bellow, I conclude, by the fact there was only enough distance to maybe touch, that there wasn't enough pressure to make the seal. This leads me to believe that the SEI bellow was for whatever reason not long enough to make the seal. As I said, I'll be able to confirm this once I receive the OEM bellow and compare measurements. But you guys were right about the spot of leakage even though I had it installed correctly.
Thanks
 

tpenfield

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I sure could use a picture or sketch of what you are talking about, because from the words I am just not seeing it . . . but it just does not sound right at all.
 
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mx77racer

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I sure could use a picture or sketch of what you are talking about, because from the words I am just not seeing it . . . but it just does not sound right at all.

DriveHousing.jpg
BellHousing.jpg


In the top image the green line indicates a 2" measurement. In the bottom image the red line indicates the 2" measurement to the point where the bellow is properly installed. For this to be water tight when all is assembled the green line should be slightly larger than the red line so that the lip of the drive housing presses into the rubber bellow. My bellow was installed in the proper ridge, but it didn't extend far enough to make a good seal.
 
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tpenfield

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Ok, thanks . . . very helpful. What outdrive is this . . . Alpha or Bravo? I am wondering if you got the wrong bellows or something like that. Even the aftermarket parts should work . . . they just may not be quite as good as OEM, bit fit and function should still be there.
 

mx77racer

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It's a Bravo 2 outdrive and the replacement kit was obtained thru ebay for Bravo models. The product had a 4.8 rating from 18 reviews. I suppose they could have packed the incorrect bellow when they pulled the order. All the parts for the kit were just placed in a box with no individual part numbers to verify. I'll know for sure tomorrow after I receive the OEM bellow.
 

mx77racer

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It really wouldn't surprise me if I did receive the incorrect bellow. That's just been my luck this year. I bought and installed a closed cooling system on this boat and couldn't understand why it kept over heating. I searched and searched for something I did wrong. I finally discovered the system came with a 200 degree thermostat instead of a 160 like it was supposed to. I was the first to discover this problem of the vendor shipping incorrect parts.
 

tpenfield

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It really wouldn't surprise me if I did receive the incorrect bellow. That's just been my luck this year. I bought and installed a closed cooling system on this boat and couldn't understand why it kept over heating. I searched and searched for something I did wrong. I finally discovered the system came with a 200 degree thermostat instead of a 160 like it was supposed to. I was the first to discover this problem of the vendor shipping incorrect parts.

I'm curious if it was the San Juan Engineering (SJE) cooling system ? I put the SJE Full system on my 7.4 MPI engines about 5 years ago. I had a similar issue with the thermostat . . . the engine would have wild temperature swings . . . I took the thermostats out that came with the kit and put back the original ones. :thumb:
 

mx77racer

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I'm curious if it was the San Juan Engineering (SJE) cooling system ? I put the SJE Full system on my 7.4 MPI engines about 5 years ago. I had a similar issue with the thermostat . . . the engine would have wild temperature swings . . . I took the thermostats out that came with the kit and put back the original ones. :thumb:

No, it was made by Monitor Products and distributed by Performance Product Technologies.

Update from above -- I received the OEM u-joint bellow and installed it. After taking the same measurements as I indicated above, I learned that this new bellow is 1/16" longer when installed (in my image, red line shorter), so I'm thinking that will make the difference in it not leaking. I don't know when I'll get to water test it but I'm hoping this problem is solved.
 

drolds72

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Jul 29, 2010
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sounds like the big foam ring that gets adhesive in front of the u-joint bellows is missing. Did you install that?
 
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