How long do drive bellows last?

[spannerman]

There is a vast difference in the quality and thickness of the rubber between VP and Merc, merc being vastly superior. Having changed literally hundreds of bellows we use the following rule of thumb, VP say every two years, we do them every year as they only cost £40 plus fitting, I have seen a new VP bellow cut from ice in winter allowing water into the boat.
Merc bellows are twice as thick and they say every 5 yrs we do them them at 3 yrs.
Exhaust bellows we change on condition as 99.9% of their life they are full of seawater so pose no threat of sinking if they split.
I prefer to think of it as cheap insurance by changing bellows inside the specified time as it will cost much more to replace universal joints, intermediate shafts, or worst case a sunken boat.
A sail drive diagphragm should be done at 8 yrs but have seen them as old as 15 yrs, these are very tobust but the boat will go down very quickly if it leaks and isn't discovered in time.
Another bearing is the useage and the temp of the water the boat operates in, cold water making the rubber very stiff, also it depends on if the boat is stored on land for long periods, we always spray the bellows with silicone spray to keep them supple.

 

[Andrew_Fanner]

Every post like this reminds me why I have shafts I too am surprised by how little time these things seem to last and the ballache of having to have the boat out to change the things.

 

[A_8]

I've found barnacles and the annual high pressure wash to be the main cause for damaging the bellows, if they are old they break easier.

However I don't think a boat (with VP engine) will sink if there is a hole, the water might enter the engine and as long as it holds the oil it should hold water....but water in the engines is not a good thing.
If it does not enter the engine it will quickly damage the gear joint.

I change mine (VP) every year and after a pressure wash (unless I did it myself and know there was no direct wash)

 

[[2068]]

>However I don't think a boat (with VP engine) will sink if there is a hole, the water might enter the engine and as long as it holds the oil...

Umm, no. Proper mechanics please correct me, but the upper UJ on a DP-290E is DRY, hence no oil. Any water that gets past the upper bellows just goes into the bellhousing, and down&out into the bilge, ruining the starter motor on the way past.

dv.

 

[tillergirl]

Very helpful. I'll pass that onto my neighbour. You say £40 plus fitting. What's a typical cost of fitting on 270's please?

 

[oldgit]

Do my Volvos every 2 years.
Leave it longer at your peril.It will cost a fortune to replace U/Js + transom shield bearings etc and instead of just a quick leg off its a blimming engine out jobby...............

 

[spannerman]

I am talking Norwegian prices here which bear no relation to the rest of the planet! At the dealer the labour is 2 hrs for changing bellows, drive oil and anodes on VP270, @ £ 70 ph plus 24% VAT. Although a good mechanic can do it in about 1 hr.

Should be cheaper in the UK ???

 

[tillergirl]

Thanks. 24% VAT - ugh!

 

[capnjack]

Thanks to all for your input on this one. Far too many to thank individually, but special thanks to Jez, your logic as per usual is outstanding and I take my hat off to you, your learning curve must be vertical by now.
Spannerman, I enjoyed your article about Bellows removal, back in March I think, through the bell housing and again thanks for the contribution to this topic.

My little sportsboat was grumbling the other day so I removed the leg to find a rather nasty looking mixture of rusty brown sort of greasy come chalky substance on the inside of the bellows, UJ's and gimble bearing, with a similar mixture but harder crusty deposits around the shift cable where it comes into the bell housing. So, its either leaking there or the bellows are split???? /forums/images/graemlins/confused.gif No sign of leakage past the rubber bell housing gasket though.

Bellows, gimble, shift cable, etc, were replaced early 2005. Haven't removed bellows yet to inspect, but maybe they were damaged on installation, or maybe there's a leak elswhere??

 

[Whitelighter]

/forums/images/graemlins/blush.gif No problemo