What is the function...?

...of the rubber bellows that covers -- I think -- the universal joint at the connection just outside the transom where the outdrive connects to the engine? Is it supposed to contain the oil that's splashed on that joint?

Keeps out the water

Drive is sealed...and is supposed to be regularly tested to see if it withstands both pressure and vacuum. The joints in the universal need to be protected from sea water and are prelubed with grease. Even a small puncture in the bellows will cause failure of the bearings in the universal in short order.

jaschrumpf said:

...of the rubber bellows that covers -- I think -- the universal joint at the connection just outside the transom where the outdrive connects to the engine? Is it supposed to contain the oil that's splashed on that joint?

Click to expand...

What you are describing is your "universal drive shaft bellows"!
And yes...... the bellows keeps the bearing crosses, universal drive shaft, main drive gear seal and the PDS bearings dry!
And no..... there should be NO oil in this area!
If you do see oil, it would indicate a main drive gear seal failure.
The bellows component is also a "wear" item and requires routine replacement.

If this area has been wet, there is a good chance that your PDS bearings have also been wet. If so, be sure to replace these bearings.
A failure here could be very expensive.

In order to replace the drive shaft bellows, you will need to remove the helmet pin and raise the helmet up and out of your way.

You will then remove the rear shift cover and disconnect the vertical linkage rod from the eccentric piston.

There are four (4) fasteners that hold the transmission in place...... two 3/8" NC nuts and two 3/8" NC cap screws will be removed.

The rest is fairly straight forward.


O-rings do not make it second time around, so be sure to replace the four (4) O-rings with OEM or equivalent!
The s/p drive = 30W engine oil....... the Duo Prop drive = GL-5 gear oil!
If you will store the drive fully down and aiming straight forward in the future, you will extend the life of the drive shaft bellows!

A minor point: I recently removed the upper from my 275. Everything worked as described above, except for removing the clevis from the eccentric on the upper. As my photo shows, it was not possible to push the pin in far enough to free the clevis from the eccentric:

I had to remove the push rod from the intermediate instead. I've owned it since new, so I've got to conclude that it came from the factory that way..??

djhinca said:

A minor point: I recently removed the upper from my 275. Everything worked as described above, except for removing the clevis from the eccentric on the upper. As my photo shows, it was not possible to push the pin in far enough to free the clevis from the eccentric:
View attachment 19119
I had to remove the push rod from the intermediate instead. I've owned it since new, so I've got to conclude that it came from the factory that way..??

Click to expand...

Here is my reason for my suggestion:

When I was active doing AQ series repair (24 years), all too often an owner would bring me a transmission for an over-haul.
The vertical linkage was still attached to the eccentric piston.
Somewhere along the way, the transmission had been bumped, causing the leverage of the linkage to bend/distort the soft brass eccentric piston ear.
If we remove the clevis pin and leave the linkage arm disconnected, this will not occur!

Try shifting into a gear.
The piston will protrude some as it moves towards it's detent.

Also, most clevis pins are installed from the AFT side inward, with the cotter pin on the FWD side towards the gear case.


.

Thank you for the detailed answer. As far as I can tell, this girl hasn't been in water since 1994, as that was the date of the registration sticker that I replaced. I'm guessing that the leaking oil is from the outdrive, as I had filled that earlier in the summer and when I checked it yesterday it wasn't reading at all on the dipstick, but the engine oil level was OK. I can get the bellows kit local, so I'm hoping the shop has or can get the drive seal and O-rings as well.

Ricardo, after comparing your diagram to my outdrive, I see differences. My drive has a steering rod coming out above the helmet and going into the top of the upper gear housing. What do I do with it? Also is there a cover plate on the rear of the upper housing that I need to remove to get to the 2 allen head bolts, and to cotter pin and cleavis and eccentric piston? The attached photo will hopefully give you an idea of what I'm looking at.

I believe that drive is called the "Aquamatic" from way back when. Should have been retired 40 years ago was debuted in 1959

Well, it was only made 54 years ago, so it's got a little life left in it. Plus I just scored off the web a 48-page PDF of the Volvo Workshop Manual for the Aquadrive 100 and 100B. If anyone would like a copy, let me know.

Jaschrumph, I spent 24 years doing service work on the Aquamatic stern drives, or what we refer to as the “AQ series”! It’s hard to beat the later AQ series designs...... especially the last of the AQ series that ran into 1996!

The best advice that I could give you would be to cut your losses on the AQ100 drive. Find yourself a later AQ series drive and use it!

I get what you're saying Ricardo, but I spent $1000 for the boat and trailer. I haven't really spent anything on the engine/outdrive so far. New plugs and impeller is all I've spent on the engine to this point. So right now, I don't really have any losses to cut to this point. I think you told me before there was no better outdrive that I could connect to that engine (a BB70), and I know you said I'd have to modify the hole in the transom for a more modern unit. I'm thinking if I have to repower I may as well just go with an outboard

Understood!


If you have the AQ 100B, you may be able to find parts for it.

I must be the luckiest SOB to ever dive blind into a boat rebuild. Today I went to the marina, armed with the printed page on how to remove the upper unit and had at it. I'd removed the steering column and the four bolts on the top of the upper unit, and was tapping on the top plate trying to loosen it when the gentleman working on the boat next to mine asked me what it was I was trying to do. I told him about the bellows and that I was trying to separate the upper unit from the middle to get the drive off. He quit what he was doing and walked over, looked at my drive for a moment, then pointed and said if we removed these bolts and those pins, we could pull the entire drive off the drive shaft in one piece. We did and it did, but I ran out of light so I left it for later.

Lucky for me he stopped over to see what I was doing. I probably would have made this a lot harder if I'd kept down teh path I'd started.

Good luck with your project!



Forgive me in my post #4 for not realizing that you were asking about a 100 drive, as your thread title made no mention of this.
Plus.... we rarely see any questions regarding an old 100 drive.
My comments and image (in post #4) relates to the later AQ series drives.


FYI...... for any 200/250 drive and later, we never remove an entire stern drive for drive shaft bellows replacement.
We remove the transmission ONLY!

And if for some reason the Intermediate housing and/or lower unit must be removed, when going back together we re-install the Intermediate and lower, then install the transmission separately and last.
Much easier this way!