Volvo dripless just replaced but still leaks

[timc4662]

Hello All,

New boat owner (and forum member) here having just bought a Gibsea 312 a month ago.

It’s got a Volvo dripless seal which was picked up on the survey and replaced as part of the sale… but unfortunately it is still leaking (mostly at idle). It seems to be vibration related as with a few revs on it’s ok.

Here’s a video of it on YouTube

I’m trying gauge whether I should get this re-looked soon or wait a bit. To my un-experienced eye the vibration does not seem serious enough to cause leaks by design. Surely this would affect the masses if normal (the leak not the wobble).

One other thing - regarding burping. How had should you have to press to get water out. For me is a pretty light squeeze and I get a good flow of water out. I was expecting it to be fairly tough requiring a bit of force.

Cheers.

 

[rotrax]

I suspect the second lip is folded back. Try using the 'Fitter' and push it back into place.

The fact you can get an easy flow of water without squeezing too hard leads me to believe this is the trouble.

 

[Tranona]

Normal that burping needs only a light squeeze as you only need to distort the lip seals a small amount. Suspect your leak is because the shaft is not centred in the tube so is running off centre through the lip seals. Relatively simple to fix by disconnecting the shaft from the gearbox pulling the seal forward and using wedges to centre the shaft. Then re-align the engine to the shaft coupling, remove the wedge and slide the seal back. Obviously needs to be out of the water to do this. Misalignment could well have been the cause of the original leaking.

 

[Jerbro]

I’m no expert, but if I observed that on my boat, I’d be looking at the engine mounts and cutlass bearing (or anything supporting the shaft for that matter)… just seems like too much movement given the shaft isn’t actually rotating…

 

[timc4662]

I’m no expert, but if I observed that on my boat, I’d be looking at the engine mounts and cutlass bearing (or anything supporting the shaft for that matter)… just seems like too much movement given the shaft isn’t actually rotating…

Agreed I’m not keen on the movement and definitely would like to get it sorted. I’m just surprised that it causes that amount of dripping regardless. Maybe there are a few things going on.

 

[timc4662]

Normal that burping needs only a light squeeze as you only need to distort the lip seals a small amount. Suspect your leak is because the shaft is not centred in the tube so is running off centre through the lip seals. Relatively simple to fix by disconnecting the shaft from the gearbox pulling the seal forward and using wedges to centre the shaft. Then re-align the engine to the shaft coupling, remove the wedge and slide the seal back. Obviously needs to be out of the water to do this. Misalignment could well have been the cause of the original leaking.

Thanks, stupid question.. are ‘the shaft being centred’ and alignment different things? I.e it could aligned, but off centre?

 

[Channel Sailor]

To burp mine seal it was not slight force, it needed to be be quite a firm squeeze. Especially if the weather was cold. I cannot see evidence of grease in the shaft, assuming it has not been carefully wiped off, then in a new install I would see traces of grease. Wondering if it had it fully greased. Also, as others have said, maybe the seals lips are distorted.

To my eye the vibration (from the engine end) at tick over in that short vid does not look excessive. Not sure about from the propellor end, cannot judge either way from that vid. The plastic collar installer thing is usually left on board by the engineer.

Possible the shaft is scored with grooves, but the engineer should have pointed that out or at least maybe put the seal lips not on the previous grooves.

 

[Malish]

To burp mine seal it was not slight force, it needed to be be quite a firm squeeze.

I've always found it easier to lift from below rather than squeeze both sides, much less effort for the same efffect.

 

[Pye_End]

Thanks, stupid question.. are ‘the shaft being centred’ and alignment different things? I.e it could aligned, but off centre?

Yes, absolutely.

 

[vyv_cox]

Thanks, stupid question.. are ‘the shaft being centred’ and alignment different things? I.e it could aligned, but off centre?

Indeed they are. I have noticed that several guides to alignment fail to mention that the shaft must be central in the stern tube before the engine mounts are touched. Otherwise it is quite possible to have the shaft perfectly aligned with the engine but touching the stern tube, which not only would knock when running but wear the cutless bearing unevenly (and quickly).

 

[barca nova]

Thanks, stupid question.. are ‘the shaft being centred’ and alignment different things? I.e it could aligned, but off centre?

There are two sorts of alignment - off centre and angular. A shaft that isnt straight will also "throw" a bit like a skipping rope.

But to go back to the beginning and tackle the issue stage by stage. You first need to check that the lips on the lip seal are "pointing" in the right direction. If I remember correctly the seal comes with a plastic gadget that encircles the shaft and is pushed into the seal to make sure of this on installation. No engine is vibration free and I would be surprised if the level of vibe shown in the video was enough to cause this issue but worth checking both alignment and engine mounts anyway. I wonder if the shaft is a bit worn - for the seals to work they need to run on a fairly smooth surface and the previous seal may have worn a groove in the wrong place. If so the only realistic cure is a new shaft which will involve a lift out but is a reasonable diy job.

 

[rotrax]

If the OP has not used the 'fitter' to push back the lips should they, in fact, be displaced, everything else is a definite maybe.

I have used four Volvo type seals on three vessels. All were faultless in use.

All required a firm 'Squeeze' to burp. The OP stating it needed only a 'pretty light squeeze' suggests lip displacement to me.

 

[MikeBz]

... I wonder if the shaft is a bit worn - for the seals to work they need to run on a fairly smooth surface and the previous seal may have worn a groove in the wrong place. If so the only realistic cure is a new shaft which will involve a lift out but is a reasonable diy job.

I had a leak from the rear crank seal on an MD2020, investigation found some wear on the crankshaft surface. Looking into that I found that press-on sleeves were available. In my case replacing the crankshaft seal solved it. I wonder if similar sleeves are available for propshafts.

 

[timc4662]

Just to add to this thread, I’ve now found that a 1 inch seal has been installed and the shaft is 25mm.

I’m now wondering if this could is be the cause. Has anyone tried this setup? Suspect?

The only reason I can think this would have been done is the stern tube size seems like it wouldn’t fit the 25mm-42mm one.

Any thoughts?

 

[Stemar]

Wear on the shaft could also be a factor. I wanted to fit a dripless seal to my Snapdragon, but the shaft had visible wear rings, so I had to go for a PSS seal.

 

[Tranona]

Just to add to this thread, I’ve now found that a 1 inch seal has been installed and the shaft is 25mm.

I’m now wondering if this could is be the cause. Has anyone tried this setup? Suspect?

The only reason I can think this would have been done is the stern tube size seems like it wouldn’t fit the 25mm-42mm one.

Any thoughts?

Yes. that 0.4mm difference is critical. Fit the correct size and your problem solved.

 

[timc4662]

Yes. that 0.4mm difference is critical. Fit the correct size and your problem solved.

Cheers, yeah it doesn’t sound a lot but actually when I had the gauge on 25.4 there’s quite a bit of play. It would be interesting if this had worked for anyone, but suspect not.

Fingers crossed I can fit another smaller Volvo, otherwise it’s a PSS.

The positive is I’ve watch so many YouTube videos now I can probably do this myself - I wish I had last time

 

[Tranona]

Cheers, yeah it doesn’t sound a lot but actually when I had the gauge on 25.4 there’s quite a bit of play. It would be interesting if this had worked for anyone, but suspect not.

Fingers crossed I can fit another smaller Volvo, otherwise it’s a PSS.

The positive is I’ve watch so many YouTube videos now I can probably do this myself - I wish I had last time

No problem getting a volvo or better a Radice. The stern rube diameters are the same. BTW even worse if you go the other way and fit a 25mm on a 1" shaft and you wonder why the shaft won't turn easily and it makes a horrible noise when running! There is a reason why size is important!

 

[rotrax]

That is OBVIOUSLY why only a light squeeze was needed to 'burp' it.

I suggested it was a displaced seal flexible lip, it turned out it was wrongly sized!

I almost feel vindicated in my 'far distant' diagnosis!

 

[Stemar]

No problem getting a volvo or better a Radice.

I'd go for a Radice, rather than the Volvo one because the Radice has a breather tube that means you don't have to burp it when you dry out.