Mercruiser Bellow Life Expectency?

[tank1949]

I purchased a used boat with twin MC Bravo "stroker" v8s. ODs are clean but former owner can't remember when bellows were replaced. I have one OD off boat and have inspected and found no cracks or wear marks on bellows. Boat was a trailed or stored dry and never bottom panted. Since I am also replacing trim sender and limit switches, I am having to remove bellow's ring. I can't remember life expectancy on bellows. Shift and exhaust bellows look new and drive shaft bellows very good. Any suggestions???

 

[harringtondav]

If you are planning on replacing the trim/limit switches on both drives (?) I'd replace all of the bellows at the same time. Replacing the switches is much easier with the bellows out of the way, and the bellows are relatively inexpensive - for your peace of mind. Bellows can last a long time. I've had 10 yr old bellows that were fine, but I replaced them when I was in there for other repairs. But I've also had and seen torn bellows, mostly due to cruising over river sticks and branches during floods.

 

[achris]

Unlike Volvo drives, Merc bellows don't have a defined life. I've seen 20 yrs old bellows that are still fine. If they don't have any fine cracking and are generally in good condition, why replace them?

 

[eric102]

I wonder if mine are the oldest on record? Bravo 2 OD 27 years old and still in good shape (visually). The only issues so far have been the trim senders were replaced once and the clamp on the shift cable bellows rusted off.

The boat sits on a trailer 99% of the time with the OD down, less than 400 hours on the engine and most of that was in the first 10 years.

They do make me nervous though so I will be replacing them before the next season.

 

[Scott Danforth]

With any new to you boat, do all the maintenance, including pulling the drives, inspecting the bellows and gimbals, check the alignment

 

[achris]

... and the clamp on the shift cable bellows rusted off....

Replace it with a 'fuel line' cable tie, or a 'normal' cable tie doubled round.

 

[tank1949]

I was able to finally speak with former owner. He stated that he replaced bellows when he installed new engines. They look in really good shape, but when I replace senders, I will have a closer inspection. No cracks so far are visible.

 

[tank1949]

Unlike Volvo drives, Merc bellows don't have a defined life. I've seen 20 yrs old bellows that are still fine. If they don't have any fine cracking and are generally in good condition, why replace them?

I don't want to unless absolutely necessary. $$$$$ This boat had always been on trailer or under covered shed. Last week, former owner indicated that he replaced bellows when he replaced motors. THX!

 

[Lou C]

I replaced the one on my OMC Cobra (same as a Volvo SX) at 11 years old. The difference between new and 11 years old was that the old one had some very small cracks in the inner folds and the rubber was more stiff than the new one. So if the bellows has no small cracks starting (look in the folds) and the rubber appears flexible, not stiff I'd say they are fine.