Question about bellow replacement

ach1982 · **Joined:** Tue Jun 10, 2014 7:01 am **Posts:** 80

Hello,
I plan to replace the two bellows on my Cobra SX drive. The bellows have small cracks on the surface, but still no holes.

The workshop manual says, that I have to remove the prop and to train the tramsmission fluid.

Is it really necessary to drain the fluid and remove the prop?
The gearbox should be sealed, or not?

Some help would be very nice.

Regards

ric · **Posted:** Tue Jan 27, 2015 4:03 pm

ach1982 wrote:

Hello,
I plan to replace the two bellows on my Cobra SX drive. The bellows have small cracks on the surface, but still no holes.

The workshop manual says, that I have to remove the prop and to train the tramsmission fluid.

Is it really necessary to drain the fluid and remove the prop?
The gearbox should be sealed, or not?

Some help would be very nice.

Regards

When was the last time you changed out the drive fluid? Removing a prop takes 30 seconds.

Surface Interval · **Posted:** Tue Jan 27, 2015 5:22 pm

It should not be necessary to pull the prop and drain fluid to change the bellows. You will have to pull the outdrive and removing the prop and draining fluid may make the outdrive easier to handle (maybe). You will want some sort of a stand or support for the outdrive. Wrestling that thing could ruin your back. You may need to pull the trim/tilt pivot bolts to get a bit more room for changing the top (driveshaft) bellows.

LouC · **Posted:** Tue Jan 27, 2015 6:17 pm

No need to change the drive oil unless it's due. I find it easier to pull the prop to get my stand under the drive. I strongly recommend using a drive stand because getting it back on can really strain our back. To pull the drive put the drive in neutral. Slide the stand under the cav plate and remove the nuts that hold the trim ram rod on. Then you have to slide that rod thru to release the trim Rams. I like to grease that rod with OMC triple guard grease to make it easier to remove.
Next remove the six nuts that hold the drive to the pivot housing. Then slide the drive off .

make sure that the sealing surface of the gimble housing is clean and free of corrosion.

NiagaraChillin · **Posted:** Wed Jan 28, 2015 12:17 am

Yep to all the above, but save your money and just get a new drive bellows, no need for an exhaust bellows, they are designed with slits along the bottom to let water and exhaust out. So if they have cracks or holes even, it doesn't matter.

Also, be aware that the drive bellows has an internal wire that loops around the inside of the bellows for rigidity. Don't remove it, you'll be tempted to just to make install easier, but don't, you'll never get it back in (don't ask me how I know). Some find it easier to remove the tilt bracket (what your drive attaches to with those 6 bolts).

LouC · **Posted:** Wed Jan 28, 2015 10:18 am

And remember these 2 points:
1) there is a ridge inside the sealing surface of the bellows that fits on the gimble housing and it has to fit into the notch that goes all the way around that housing.
2) the all rubber style bellows is made so that the lower side has 7 ribs and the upper side has 6. It is made this way so the rubber does not get stretched when you tilt it up. So orient it so that the 7 ribs are facing down. I don't know how the newer style plastic and rubber ones are made.

ach1982 · **Joined:** Tue Jun 10, 2014 7:01 am **Posts:** 80

Thanks a lot for your helpfull replies.

Last fall the boat had a visit in the boat-workshop for winterizing.
At this time the transmission fluid was exchanges.
So I don't want to drain.

During the inspection in the workshop, no one has told something about the bellows.
While cleaning the boat at home, I noticed, that the bellows have small cracks on the surface, no holes.

I read the omc workshop manual and I think it is not difficult to change the bellows, but they say, I have to drain the transmission fluid.
Normally I repair everything on my car. So I think I have some.

For dismantling the z-drive I'll build a small cart, high enough for the prop.

LouC · **Posted:** Wed Jan 28, 2015 2:13 pm

Ah are you in Europe, I know there the call outdrives Z drives. Yes you do not have to drain the drive fluid.
The bellows can be changed 2 ways:
one is the way described in the shop manual and that involves removing the pivot housing. First you have to disconnect the shift cable. Then remove the pivot housing. This way gives you a lot more room and may be best if its the first time you are doing it.
Second way is to remove the exhaust bellows first. Be careful removing the snap ring on the exhaust bellows, it can pop off and smack you in the head. No I did not learn that the hard way LOL.
After you remove the exhaust bellows you have just enough room to get the driveshaft bellows off. But as I said above, make sure the mating surface is in good shape and the bellows is on the mounting surface right (ridge in bellows fits in notch in the gimble housing) and oriented right (7 ribs on bottom if old rubber style).

To be sure it needs to be changed, try this:
tilt the drive all the way up
get a bright LED flashlight
put on some gloves to protect your hands
grab the exhaust bellows and pull it down, so you can see in between the folds of the driveshaft bellows. If you see cracks there, then replace it. If not and if its dry inside when you pull the drive off then its still good. That's what I've been doing and mine has lasted 10 years. In salt water moored 6 months out of the year.

ach1982 · **Joined:** Tue Jun 10, 2014 7:01 am **Posts:** 80

You're right. We say z-drives instead of outdrives. I'm from germany.
I think this can be also noticed on my mediocre englisch. But I'm tryin'.
Next time I'll use outdrives.

I think it's great that you can get so much help here in this Forum. The Members are very nice and helpful.
In some german forums, the members are arrogant and unfriendly, when you ask such basic questions like me.
Certainly because these questions are below their personal skill level.

Thank you very much for your detailed instruction.

I'll take some snapshots of the bellows with the LED-flashlight inside. Then you can tell me, if I've to replace them.
This can take four to six weeks, becaus we've wintertime and my boat is located in the "winter camp" (

I do not knot the right word).

Best regards from germany

LouC · **Posted:** Wed Jan 28, 2015 7:48 pm

Sounds good, your English is fine by the way.
One of the first words I learned in German was Zundflogle (which I think means firing order) because my first vehicles were air cooled Volkswagens and it was stamped on the engine crankcase "Zundfloge 1432"....
I spend many hours learning the the basics of auto mechanics on 2 VWs I owned back in the early to mid 70s. A 1956 Beetle that was converted into a Dune Buggy in 1969 and a 1965 Beetle. I used to use the same engine in both VWs. I put it in the buggy in spring, summer and fall and then transplanted it back into the Beetle in winter. Those were simple easy to repair vehicles. Also unlike many Americans I taught myself the metric system working on these. 1 CM-3/8th of an inch lol.

ach1982 · **Joined:** Tue Jun 10, 2014 7:01 am **Posts:** 80

Thank you very much.

Yes, indeed "Zündreihenfolge" means firing order.

The old beetle is one of the best german classic cars. It runs and runs and runs.... (Translated it is an legendary old Volkswagen advertising tv spot).
The new beetle is an modified golf with a rounded body. I'll prefer the old air-cooled rear engine version. This is almost like a Porsche

.
Unfortnately here in Germany you can find only a few models in a good condition.
Many of them were eaten up by rust. The climate is simply too moist.
The few good ones you can find are very expensive.

I'm convinced, that you can find more good conditioned models in the US, where you have a drier climate.

My brother has a 1983 Bully T3 in a very good condition, bought from the firefighters of a small village.
It has nearly the same basis like the good old beetle.

Two weeks ago I bought two do-it-yourself manuals for the OMC engines and z-drives ;-)

.
Since I bought this manuals, everyday I learn more and more englisch technical terms.
There are no translated manuals in germany. You can find only two englisch ones in our bookstores and on amazon.de.
Now I've the seloc and the clymer manual. I think they differ only a little from each other, but they were the last two ones which were offered on amazon.de. So I bought them.

At the beginnig the imperial system

was confusing me. Furthermore it is difficult to find affordable "inch" tools.
Now I understand it.

LouC · **Posted:** Thu Jan 29, 2015 4:39 pm

If you find any instructions in the manual where the meaning is not clear, you can post it here and we can help explain. I have the factory manuals for my 1988 OMC Cobra and they are very good.
I recall when I switched to Japanese cars I found the manuals as they were translated into English sometimes a little difficult to understand.
As far as old VWs and Porsches, here in the northeast US its also very damp, like Germany but hotter in summer and colder in winter. If I wanted a vintage VW or Porsche I'd have to get one from the desert Southwest. Nothing rusts there.
My 65 Beetle was nearly completely rusted out by '75.
Then Porsche switched to a zinc galvanized process I think. A friend has a '85 944 it is still pretty rust free. Lots of other problems but rust not much at all.

ach1982 · **Joined:** Tue Jun 10, 2014 7:01 am **Posts:** 80

Hi,
do I need a gasket between pivot housing and gear housing?

I some stores you can find a set of bellows and gaskets like this one: http://www.ebay.de/itm/like/32160833022 ... 106&chn=ps
and in some other stores you can find some with gimbal bearing and without a gasket: http://www.marine-discount24.com/gimbal ... cobra.html

And one question more...

Do I need an alignment tool for the installation of the gear housing after the replacement of the bellows.
Or is it only necessary, when after the replacement of the gimbal bearing.

regards

ach1982 · **Joined:** Tue Jun 10, 2014 7:01 am **Posts:** 80

And if I need this alignement tool it would be very nice, if someone can give me the dimensions.
I have the opportunity to produce it with a lathe by myself.

LouC · **Posted:** Fri Feb 06, 2015 5:19 pm

OK....there is a some confusion between a pure OMC designed Cobra built from 86-93 and the joint venture models built with OMC/Volvo from 94-98.....the former, had dog clutch shifting in the lower gear housing like an outboard, the latter has Volvo style cone clutch shifting in the upper gear housing....
The first set you linked to is for the OMC Cobra 1986-1993, that is pure OMC before the joint venture with Volvo Penta.
The second set is for the OMC Cobra/Volvo Cobra SX which was the joint venture product, built from 94-98, after that OMC got out of the business and Volvo took over the production and called it the Volvo SX. Same thing though
The driveshaft bellows are the same part. The lower bellows (exhaust bellows) are also the same as far as I know.
The one big difference? The pure OMC Cobra used the gasket between the drive and the pivot housing, the joint venture and later Volvo SX models do not. That little o-ring style gasket is also the same between the 2 different drives.

The reason for the commonality is that during the joint venture years, Volvo/OMC took the original OMC Cobra design, and left the transom mount mostly the same, modified the pivot housing and the whole drive unit while it looks similar is totally different. The joint venture models and Volvo SX have a hump across the top of the upper gear housing, the pure OMC models are flat across the top.
You should check the engine alignment when you have the drive off, even if not changing the gimble bearing. I don't know the dimensions but I bet you can find that on the forums at iboats.com. Sierra sells this tool, you can find it at various retailers, or you can make one.

www.iFourWinns.com

Question about bellow replacement

Who is online