Bravo sealing issue
 

Hi guys I’m new hear I am having trouble with my bravo one I just replaced the gimbal bearing because of water intrusion and replaced bellows with Sierra parts only to have the ujoint bellow leak still. The knee lip on gimbal
housing end is in location and put on with bellows adhesive, the bell housing end I pulled through so both ribs are inside bellhousing and installed a new retainer sleeve. I just redid the u joint bellow again but with factory Merc parts and still won’t seal, I replaced because I was thinking maybe it’s a parts issue with Sierra quality but same problem. I also measured how far the sealing face of the bellow sits in from the bellhousing mounting face and measured the protrusion on the gear case that seals to the bellow and they are both about the same dimension. I would have though the protrusion on the gear case would have been a little longer than the recess to bellow face so it could squish into it and seal. Am I overlooking something, it’s a pretty straight forward and simple job never had this happen before and I am stumped. Thanks

Tough one...Using Second groove of bellow on drive end?

yes second groove on bellhousing end gimbal housing end is in groove there with bellow adhesive and brand new hose clamp and retainer sleeve. It almost seams like the part of the upper housing does not go into the bellhousing enough to seal. The mating surfaces are in good condition. I measured how
far the drive goes into the bellhousing and wear it seals and how far in the bellows are from the sealing face and there is maybe 1/32 of compression to bed had when the are bolted together to seal. Just doesn’t seem like enough. Also the end of the drive is in very good condition so it should seal
on the bellow face but still not. I am stumped

While Sierra and Merc parts are physically the same, the only issue would be if they last as long. That not being the case for your question, your double lip is as seen in the pic? If it is then something else is not right


https://cimg1.ibsrv.net/gimg/www.off...599617c15f.jpg

Yes the bellow is installed the same as in the diagram, also new o rings. I took it apart again and everything is correct but still leaking. Does any body know how the dimension from upper drive mounting face to the end he of where it seals to the bellow. I am getting 52 mm there and from bellhousing mating fave to bellow seal ring is 51 3/4 mm almost 52. Which leaves .010 to .020 of an inch to makes contact and seal. I will be pulling it again to look for anything that I could of missed

Crack in the housing maybe

Are you 100% sure it is a leak from the bellows? Can you see where it is leaking from or just noticing water in the bilge?

Well under further investigation the steering shaft seal is leaking but I do find water in the u joint bellow. I didn’t think water could get in there from the steering shaft leaking cause the seal behind the gimbal. And yes I have some
in the bilge from the steering shaft. Could it leak into the bellow from
the shaft. Run down in there somehow. I put a new seal behind the gimbal bearing

Yes it could leak down the inner part of the transom assembly and get into the ujoint bellows. Any water in the bilge can get into the ujoint bellow sadly.

Did you use bellows adhesive?

Was going to ask the same questions...how do you know the u joint bellows is your issue. Granted you are seeing water in the bellows, but as mentioned could be leaking from somewhere else. It is possible that the steering pin leaks down into the u joint area.

Yes bellows adhesive. I was just wondering cause I didn’t think it could. With the inner seal in behind the gimbal bearing how could water get in from the steering shaft. I checked all
the inter transom plate bolts
or nuts to make
sure they r tight and they r. I thought about doing the steering shaft from the outside but I don’t really like the whole ya omg to cut a hole and put a cover plate on. Does this affect the gimbal housing strength at all. Im
ki da shocked
its bad this boat was never left in the water and kept
in heated garage after use. Transom
is dry as a bone and stringers r great doesn’t seam like it had a lot of use. Just shocked it’s corroded enough to leak cause everything is spotless outdrrive is beautiful

That swivel pin is plain steel, not treated and rusts verybeasy just like a brake rotor that sits. Then when the rush is enough that seal is taken out.

That seal around the gimbal bearing is seal to keep grease from coming into boat.... as that swivel seal leaks water could come down and go in that seal the other direction.... especially once it is warmed up.

as mentioned...the steel pin is crap untreated steel. Not a 300 series. We just did our pin using the jr marine kit.

Cutting out the area for the plate is very small and not a structural issue. Thousands of boats and users have used them without issue.

here is a picture of our transom assembly. It looks brand new yet our steering pins were leaking.

https://cimg5.ibsrv.net/gimg/www.off...5a32dba18d.png