Bellows adhesive or not?

[tfret]

Im installing new U joint and exhaust bellows on an 07 SX-A drive. Neither the instructions that came with the OE kit, or the service manual call for adhesive. However my sealing surfaces were a bit corroded. After cleaning them up they are a little bit pitted. I’m considering using adhesive just to ensure a good seal. What harm if any could possibly be from this?

 

[Scott Danforth]

I would wire brush the corrosion, use a zinc dichromate primer, and some paint prior.

 

[tfret]

Yep i got it all cleaned up, primed, and painted with Volvo primer and paint. But still not perfectly smooth like it was when new.

 

[Horigan]

I use Triple Guard grease.

 

[4now04]

I would not recommend adhesive. The drive bellows is secured with a hose clamp on one end and compressed between metal drive parts on the other (or at least it is on my DP-SM). The exhaust bellows does not need to be water tight. In fact, the bellows has drain holes in it.

 

[BRICH1260]

Having a watertight seal on the exhaust bellow is not critical. As long as you have enough lip to get the clamp to tighten on you should be good. Adhesive isn't detrimental until you go to replace that bellows with the next one, it can really gum up the mounting surfaces for the next time.

 

[HiWard]

From my VP Workshop Manual AC 2(2) from 2003, on page 43:
"Coat the outside surface of the gimbal bearing bore with Volvo
Penta Gasket Sealing Compound. Sealer is not required on the
outside of the exhaust opening."

and page 61:
"Apply Volvo Penta Gasket Sealing Compound around the complete inner V-shaped lip of the pivot housing, to seal the
U-joint bellows against water entry."

Someone else may be able to confirm this, but my understanding is that VP at some point changed the bellows from a rubber type to a harder plastic type. Maybe the latter doesn't require gasket sealant?

 

[Grub54891]

I never put adhesive on the exhaust bellow. I used to but it would pull off the transom end sometimes. Then I read that it's not needed. Volvo not so bad but does happen at times. Mercruiser seems to come off almost every time with adhesive.

 

[tfret]

Hi and I appreciate the dialogue very much. Yes of course I realize the exhaust bellows isn’t critical for being water tight. The exhaust is full of water anyway. Protecting the U joints on an older drive is my priority. Weighing the difference between making the bellows replacement more difficult next time VS having a leak that ruins my U joints (non greasable), Im leaning toward sealant. I guess my question really is, what harm could possibly come from this?

 

[Scott Danforth]

if you want to use a sealant, use permatex #3 non-hardening. it can be cleaned off with mineral spirits

 

[Lou C]

When I do the Cobra bellows I've followed the OMC shop manual and used their gasket sealer on that flange, what I have found is just like with threaded fasteners, it keeps out moisture and the last time I changed the bellows (old one was in use in salt water for 11 years) the flange looked perfect. No corrosion at all. Permatex Aviation is a good alternative, it seems that both the original Merc Perfect Seal and the OMC/Evinrude gasket sealer is very hard if not impossible to find, or places that appear to be selling it, actually send you a can of the Permatex!

 

[IslandExplorer]

If you're worried about it leaking bc of somewhat conpromised surface and don't mind spending a few minutes years from now cleaning off a little sealant- then seal it up good! You'll probably feel better about it later when you're out there. I like the kind that sets vs slippery/greasy type. Think I used Quicksilver brand. I would put some on there if it were me. Won't hurt a thing. No one wants u joints that you can't see rusting.

 

[tfret]

Thank you all for the inputs!

 

[Kosmofreeze]

A timely thread since I'm finally going to change my VP DP-SM bellows that was last changed in 2011. While the rubber still looks and feels good after 14 years and 160 hours of fresh water (dry stored) it's probably time to change it. I've never done it before. The local VP shop wants over $2K to do the bellows and gimbal bearing - that's my incentive for DIY. For that kind of $$ I'm sure they'll recommend to change the rubber every year. What's a practical maintenance interval for replacing the bellows given that the boat is lightly used, fresh water and dry stored? Every 5 years?

 

[Lou C]

I look at a driveshaft bellows like I look at tires, if I see small cracks starting to form it is time to replace, that is a sign that the rubber is becoming less flexible. Tilt the drive all the way up and look in between the folds, if you compare an old bellows with a new one you can see and feel how much stiffer the rubber gets over time. Also turn it side to side, see if you see any signs of abrasion as well. In my use (salt water, moored boat 6 months, but when stored drive is down) I start to see cracks after about 10 years of use.
If the gimble turns smoothly when turned with fingers, and you're not getting any noises from the drivetrain I see no need to replace it. Mine was last replaced about 20 years ago, never any water in the bellows since then, it gets greased at the beginning of each season with the engine running and that's it.