Advice please Volvo penta 270

Hello all. My first post.
I need advice please. I am a mechanic but the stern drive is new to me.
I am m
helping a mate keep his twin penta 270 drives running and one is leaking water from the lowest point of the engine bell housing. It's not coolant from the engine . I downloaded a manual but it's not clear where the water from the stern drive flows. What I can say it it's a steady leak and if we start the engine the leak becomes very bad. We are due to lift the boat from the water soon but need to find the leak first .Is there a seal between the engine and drive or is it just the large bellows I can see looking over the stern

Any advice will be welcome.

Regards Ken

Ken, from the engine's flywheel mounted "drive coupler", there will be a PDS (primary drive shaft).
This PDS is housed and supported by the "flywheel cover" (aka bell housing in the auto world).

It will be supported via one bearing and a pilot nose and bushing........ or two bearings w/o the pilot nose or bushing.
(Which engines? This will tell me whether he has a double or single bearing PDS.)


This PDS couples the engine to the female yoke of the "Universal Drive Shaft".... which takes power to the transmission (aka upper gear unit on the AQ series Volvo Penta).


There is a bellows (I.E., rubber accordian type boot) that joins the F/C to the front transmission collar.
This bellows seals this area from the river/lake/ocean water.
These require routine replacement. (they dry out, become fatiqued due to stress, age, etc... and will split or crack open.)

If a bellows was to fail, water would not only enter the area of the Universal Drive Shaft, but it would also finds it's way into the the PDS cavity, and eventually (in your buddy's case) would make it to the inside area of the Flywheel Cover.

This often causes the need for complete disassembly, new bearing crosses, new PDS bearings, a new transmission main drive gear seal, and a new seal surface wear washer.


GM V-8 Borg Warner drive coupler and double bearing PDS (below).................... cut view of early AQ series drive (below).

Firstly thank you for your quick and detailed reply.

This had Volvo petrol engines but it has been professionally converted to use the Ford 2.5L van engines. I can't remember the code but over here in the UK the Ford transit van uses them.
He is organising getting the boat lifted out of the water so I can set about repairing it. This bellow is the one I can see when looking over the stern of the boat I assume?. Would it be leaking more with the engine running because the turbulence of the water finds its way through the hole more?. Just so it's clear in my mind is there no hoses or pumped water at that part of the stern drive?
I guess I have to remove the external part of the drive change this? What sort of weight are these drives?n

Again thanks for your elp
Regards Ken

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Kerabo said:

Firstly thank you for your quick and detailed reply.

This had Volvo petrol engines but it has been professionally converted to use the Ford 2.5L van engines. I can't remember the code but over here in the UK the Ford transit van uses them.
He is organising getting the boat lifted out of the water so I can set about repairing it. This bellow is the one I can see when looking over the stern of the boat I assume?.
The drive shaft bellows will be the upper-most bellows.


Would it be leaking more with the engine running because the turbulence of the water finds its way through the hole more?.
Hard to say.
None-the-less, any leak is un-acceptible. This area must be bone dry at all times.


Just so it's clear in my mind is there no hoses or pumped water at that part of the stern drive?
Volvo Penta has never used a drive located seawater pump. They have always been engine mounted.
The seawater path from the drive to the seawater pump is under suction.
Any air breach here will cause pump action failure.

I guess I have to remove the external part of the drive change this? What sort of weight are these drives?
In order to replace the drive shaft bellows, the transmission ONLY needs to be removed.
I would leave the Intermediate housing and lower unit attached.

Even if Intermediate housing work is required, I always first remove the transmission by itself... then I remove the Intermediate housing.
The lower unit can be removed/replaced at any time.

Ken, it is much easier to use this method, than it is to remove/replace an entire drive while at the same time fighting with the water neck hose, shift cable clamp, exhaust bellows and suspension fork hinge pins, etc. simultaneously.

If the Intermediate housing must also be removed, these areas are wide open with the transmission having been removed first.
Likewise when going back together.... install the transmission last.

Trust me on this one!



Again thanks for your elp
Regards Ken

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Ok thanks for all the information .

I know enough to have an idea as to how to proceed. With luck I will be able to see the damaged bellow. Just before this started leaking the inlet for the heat exchanger blocked with weed and an engine got quiet hot. Would it be likely that the bellow I have seen in a picture that I think is the coolant outlet would burn and split if it was just exhaust gasses and no water.
Oh how heavy are these. A hoist or crane required?

Thanks again Ken

Yes it's dripping of the lowest point of the bell housing. The engine is dry and not using or loosing water so feel sure it's coming from outside the hull. I fitted an automatic bilge pump but before then was filling the engine compartment to about 5 inches in two days. I am guessing about 50 gallons.

I will report back when I start work on it. Could be a few weeks.

Thanks again ken

Ken.............

Kerabo said:

Yes it's dripping of the lowest point of the bell housing.
Flywheel Cover! (bell housing if automotive)

The engine is dry and not using or loosing water so feel sure it's coming from outside the hull.
If Raw Water cooled, you may not know if a rear casting core plug may be leaking.
If so...., this will be the same river/lake/ocean water as though it was coming from a leaking drive shaft bellows via the PDS cavity/bore.
The leak would show up as though coming from within the interior of the flywheel cover.

You may also have a leak at the chrome water tube that comes up through the transom shield (the one that the seawater pump's suction hose connects to).

You may also have a leaking collar steering fork "V-ring" seal.

You may also have a shift cable sheathe fitting "crimp sleeve" that's gone bad.

Thanks again ken

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This is a bit off topic however I have a starline 180 cavalier Volvo penta aq131/275 engine, just wondering if there is a drain in the bottom of the bellows exhaust because the antifreeze for winter time preparation seems to be leaking out of the bellows exhaust. The guy I bought the boat from said that when winterising the antifreeze should come out the end of the exhaust, mine is draining out around where the outer bellows meets hull. Any help would be greatly appreciated!

It is always best to start a new thread for your own specific questions.
But as long as we're here................

Lemmewinks said:

This is a bit off topic however I have a starline 180 cavalier Volvo penta aq131/275 engine, just wondering if there is a drain in the bottom of the bellows exhaust because the antifreeze for winter time preparation seems to be leaking out of the bellows exhaust.
Yes, the exhaust bellows will have a weep hole that will be positioned at the bottom and towards the front.
This weep hole allows water to drain whether the drive is up or down.
(keeping your drive fully down and aimed straight forward when not in use, will extend the life of the drive shaft bellows!)

The guy I bought the boat from said that when winterising the antifreeze should come out the end of the exhaust, mine is draining out around where the outer bellows meets hull. Any help would be greatly appreciated!
Winterizing a Raw Water cooled engine by pulling AF in through the drive's seawater path is very risky!
Please read my write-up on these kits that provide this type of so called "winterizing".

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Hello again
We now have the boat out of the water and I started work on removing the drive. Not as bad as I expected and easier once I could see it than trying to understand pictures and books. I thought things would be very corroded but it all came apart easy and had it off in about 1 hour.
Anyway the top bellow had a 1" split so that should be the leak.
Am I correct that even if the bellow leaks the water has to travel through the drive shaft bearings to exit inside the boat?. The drive shaft although running in water is free and without stiffness or play.
The spline for the drive has about 25thou lift on the bearing. I would sooner not do this but what are your thoughts ?. The boat will only have small runs .
So apart from the shaft being tight on the spline it went well .

Just a few questions please.
I watched a clip on YouTube and the guy found a pin hole in his bellow and thought this should be there Is this the case?
Are these made under licence as I expected Volvo to be metric sizes but seem to be AF?
The hose I have seen in pictures is not fitted even though both spigots are there? Could this be because it has different engines fitted?
any advice on paint to use?
what type of assembly grease is recommended?

Thanks for you help so far.

Ken