Bellows lifespan?

SCORPIO

Well-Known Member
Apr 7, 2008
2,742
Delaware
Boat Info
1989 300 DA
Engines
Twin 5.7 Merc Alpha I
I had all my bellows and hoses replaced professionally prior to the start of the 2013 season., so they have had 5 seasons of use. I have no leaks and the bellows all look fine, the clamps are getting corroded but the rubber looks good. I'm in salt water for the season May-early Nov. My question is, how long do these things last? I want to replace them prior to any leakage but don't want to do a monster job before needed also. Lets hear some experiences.
Thanks!
 
If you've gotten 5 years I would say you did well. A lot of their life depends on how you store the drives when the boat is stored out of the water. You should keep the drives down as much as possible. If a drive is stored in the up position a "set" can form in the bellows in the curved position. When the drives are lowered the bellows can crack.

I would say your bellows are now on borrowed time. Five years is a long time and just about the limit I would go. I would change all the bellows now. And do the shift cable bellows as well.

Shawn
 
My first set lasted eight years and probably could have gone ten years. I'm now at ten years with the second set and they still look good. If you inspect them every year I think ten years is a safe life span. I have my mechanic giving mine an inspection next week maybe this is my year but I haven't seen anything that makes me think they need changing.
 
Sold my 2006 280 last year with the original bellows still in excellent condition. 6 of those years it was slipped in salt water for the 6 month season. Cleaned them yearly with a tooth brush and a good look over
 
If you do change them make sure you use Mercruiser or quick silver... Not aftermarket bellows... As they don't last as long and the shift cable does not line up too good... It might shift good with aftermarket it might not... Buy why take the chance....
 
You guys confirmed what I've been thinking, change them now and rest easy when the boat is in the water and Im 3 hours away.
 
Changing mine this year before going back in the water.
The boat has been wet slipped in Salt 6 months each year since new (2007), currently at 300 hours on the clock.
I have all the maintenance records from day one, with no indication that the bellows have ever been changed.
I don’t see any cracks, but found a small amount of salt water inside the bellows when i pulled the outdrive in the fall.
Water hose, U-joint and shift cable bellows are all being replaced.
 
Bellows can last a long time. For example, my boat is a 1999, always used in freshwater and stored under cover on a lift. My original bellows were replaced in 2015 - so that's 16yrs! And the bellows themselves were really still in good shape, reason I replaced is the shift bellows started leaking. Now, a boat that sit's in freshwater, not going to last that long, salt water even less. My old boat was in freshwater year around and at 5yrs when I sold it, the bellows still were in good shape. Personally since I do most of my own work, I give things like that a good inspection periodically and make replacement decisions based on that, I would not say bellows arbitrarily should be replaced every X years. BUT, I would say in salt water anything over 5yrs is entering the watch it closely period. In your case, with the boat in salt water, your are not doing the work, it requires a haulout, loss of use etc - 5yrs is a little early in my opinion, but for piece of mind maybe not a bad idea. Also, regarding aftermarket, I went with Sierra parts on mine and had no issues and really could not tell the difference from OEM - cost difference was about 25%.

The job should include:
  • U Joint bellows
  • Exhaust bellows (or exhaust tube - I went with the tube)
  • Shift cable, which would include the shift bellows
  • Replace water hose
  • Replace gear lube hose - and probably the through transom fitting that will likely break!
  • Replace Trim send and limit switches.
  • Gimbal bearing - lots of people just replace this, mine is original and still fine. Unless it has gotten water in it or not maintained with grease these can and should last the life of the boat. But it's a "while we are there" kind of thing.

The DIY job took me a weekend and cost $400 including a couple of tools I had to buy. The shop quote was $1500. I will tell you it was not easy especially doing it alone.
 
I had a 1988 in saltwater. Changed the bellows in 2012 and was a complete waste of time effort and money. They were perfect after 25 years. I would not change!!!! Used to change water pump impeller every year also. I get over 10 years now.
 
I just changed out the bellows on the twin outdrives on my 77 weekender 240. The u-joint bellows on both had water or grease in them and the gimbel bearings were shot on both of them. All the bellows looked like they were new but where it all broke down was the people who did it last time did not replace the flange gasket or water hose o-rings so thats where the water came from. The shift bellows look new and the cable as well so I would presume that is why it was taken apart the first place. It is too bad that they didn't do it correctly the first time would of saved me alot of trouble. So I put in new exhaust and u-joint bellows, gimbel bearings,all upper seals,the shift shaft seals ,and new waterpumps along with new gaskets and o-rings, didn't do the shift cable bellows as they look new. Still have to put the two halves together on the starboard side and install it on the boat, the port side is already on and ran. One thing to remember is bellows are the main spot where water can get into your boat when it is moored and can sink it, 1500.00 is pretty cheap insurance against that.
 
I just changed mine out - as best as I could tell, they were original fit (2006), one looked almost new, one looked “old”.

To be honest, if you are doing your annual maintenance properly, it’s only an extra 10 minutes labour and maybe a hundred bucks in parts - so not a whole lot to gain by not doing them, but a failure can sink the boat.....

My rule on replacements is if the mechanic is happy to guarantee the part will last another two years, I’ll leave it on for another one, if he can’t give that guarantee, the part gets changed.
 
I've finally gotten started on the bellows job. I pulled my starboard drive and removed the gimball bearing and I noticed the rubber came out of the seal that sits in front of the bearing. It looks like that seal presses in from outside the boat, prior to installing the gimball bearing. Does that sound correct? I have a new one and am getting ready to install but wanted to hear some reassurance since the manual doesn't really talk about it, just shows in the parts diagram.

I can highly recommend the Mallory gimball bearing puller tool, it made pulling the bearing a piece of cake! The tool I got also came with an alignment bar and a mandrel that fits on the bar to install the new bearing. Got it off Amazon, came in two days and worked like a charm.
I won't ever use a slide hammer again for gimball bearings.
 
For those who have done the bellows job themselves, I have a question for you, do you install the U-joing bellows to the transom plate and then try to install the bell housing or do you install the bellows on the bell housing first then install it to the transom assembly? What is your reasoning, either method?
I ask because it looks to me like one should install the bellows to the transom assembly first as those clamps seem almost impossible to get to once everything is together. Not that it looks easy at the bell housing either, just a little more room with the bell housing tilted up.
 
You have the right order Scorp. Put the bellows on the Gimbal Housing (Transom Plate is what is inside as a backing plate), be sure and use the nasty bellows adhesive and ensure the bellows gets all the way in so that the ring molded into the inside ends snaps into the grove on the Gimbal Housing and Bell Housing. I hope I explained that clearly for you. Also, some Alpha 1s have a hole in the outside of the Gimbal Housing (left) that will allow you to get a long 1/4" drive socket through to align with the hose clamp. If not the clamp needs to go 90 degrees to the right from the top with the nut facing down. A wobbly extension is very helpful. There are a couple of videos on YouTube that show the entire procedure.
Shawn
 
The seal that is behind the gimbel bearing is the seal that prevents water from getting into the coupler and engine. My merc guy said that he has never replaced one because has never seen one damaged but in your case replace it. I have worked on both my outdrives and replaced the seal on the first one. It isnt easy to remove I had to drill the seal flange and use a screw puller attachment and slide hammer to pull it. Don't use the same attachment as the gimbel bearing as you can't hook on the seal but will catch the inner outdrive flange and can damage it if you use the slide hammer on that area.
I have both outdrives on now and repaired(I hope) and now have to adjust the shift linkage as It is all screwed up from me messing with it before. I was missing the washer that was on the shift shaft seal and that prevents it from shifting into reverse thus why I couldn't get it to shift right. So now I have to figure out the process to get it all back to what it was before I played with it.
 
I NEED HELP! I got everythng apart, clean and I'm starting reassembly. I replaced the gimball bearing using the Mallory installation mandrel that fits on the alignment bar. When the bearing bottomed out, I couldn' pull out the bar no matter how hard I pulled. I had to clamp a big set of vice grips to the end of the bar and hit them with a hammer to drive the bar out. The grease seal on the outside of the bearing is now loose and floats when I grease the bearing with a gun. The alignment bar will not engage the splines in the coupler. The alignment was fine with the old bearing prior to pulling it. Is this bearing ruined? What do I need to do to properly along the bearing before I try mating the drive? This job SUCKS so far and I haven' even got to the bellows.
 
Ok, I played with the alignment bar and moved the bearing enough that the bar bottomsvin the coupler now and I can remove it by hand. However, that grease seal is not going to stay in place over the ball cage on the bearing. Is it safe to use it or should I pull this bearing and get another one?
 
I pulled the bearing and ordered a new OEM Mercruiser bearing. The damaged one was a GLM, I should have known better.
 
Sounds like you made the right call in the end. The last bearing I changed (OEM) no longer offered the option of being able to be grease externally and labelled it "lifetime". That seal is pretty important. I know a lot of people have good luck and save some money with the aftermarket parts but for me when it comes to the critical pieces, OEM only. Let us know if you see a physical difference in them as Mercruiser does not build their own bearings.
 

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