Volvo Penta stern gland

[christopherc]

I recently hauled the boat out, antifouled and refloated, but didn't give the seal a squeeze, so, having read this is what I should have done I duly squeezed and mopped up, but the gland still seems to drip a little. I've also read I should grease the lip, and will do this as soon as I can. Can any anyone tell me if this is all normal and wether i can expect grease to stop the drip, however small, or am I looking at something that is deteriorating and likely to need replacing (new in 2002)? I have found water in the bilges recently and have been trying to figure out where it is coming from. Any advice would be very welcome.

Happy New Year!!

 

[beneteau_305_553]

They should be greased every year and replaced every 5 years.

The grease comes with a plastic applicator that wraps round the shaft to push the grease into the seal.

Grease will reduce the rate of wear but it sounds like yours needs replacing as they should be dripless.

 

[Malcb]

If the water is coming from the shaft seal the you should be able to spot it under the seal. Check all other possibilities first.

On my boat, I can lift the cockpit floor, and the seal round tht was causing the problem.

 

[christopherc]

Thanks, sounds like another lift out, better make sure thats where the problem is.

 

[mariog]

I always found it hard to put grease before each season and always wonder how much grease actually goes inside the seal. But don't despair with some courage the seal can be changed in the water.

 

[Bajansailor]

We have a Volvo 2003T - age unknown, but as the boat was built in 1991 as a sail/motor away version (with no interior outfit - this was left for the previous owner to fit), I am assuming the the engine and shaft seal is of similar vintage.

I am also assuming that she had the original seal when we acquired her almost 10 years ago. The seal appears to be in excellent condition, and has never leaked a drop. We do try to stuff grease under the lip occasionally, but it is difficult to do, as noted above.

We have a complete spare seal - but I am reluctant to change it yet, based simply on age. The engine has had very little usage in the past 10 years (we dont have an hour meter, but I am sure it is less than 500 hours in total). I know that the rubber will deteriorate / perish with time, but there is no obvious indication of this happening yet.

I guess that maybe we should change it, at the next haul-out. We dismantled, cleaned up and re-assembled the stern gear during the last haul-out (had to put a gas torch on the coupling, which was rusted on to the shaft), so it should (I hope!) be not-too-difficult to get it off again the next time.

 

[jerryat]

I agree, changing every five years is completely unnecessary IMHO, provided that greasing (I've used Blakes Seacock grease for 18 years) is carried out annually.

I changed my Volvo seal last year after almost 23 years in continuous use, including ten years full time cruising, only as part of a major overall refit. 'Burb' it on re-launch/after drying out, and they seem to last indefinately - WITHOUT any dripping whatsoever.

Many of my friends have similar lengths of service from these excellent units.

 

[nedmin]

I am sure the plastic applicator that wraps round the shaft is for installation puposes only,so that that you dont damage the seal when you slide on the shaft.I just get a poly bag,cut the corner off about 1/2inch, put a cu.cms. approx of grease in a corner squeeze the seal at 180deg with your finger and thumb,then push the corner of bag into seal at 90deg.about 3/4inch then press grease out of bag,withdrawing slightly as you do.then rotate,I leave an ally takeaway meal container under to see if I get a leak,but never seen one so far.

 

[thalassa]

The plastic applicator is indeed for installation AND application of the grease; it's the best way to get sufficient grease (the right type!) on the right spot. And indeed, they last far longer than five years if you keep the seal wet & greased. However, this basic requirement should be there: the shaft should be spotless, clean, and without any trace of burrs. Quite often, people change from stuffing boxes to other seal types. A common practice is cutting cord rounds for stuffing boxes is to do this, on the shaft, with a cutter knife, resulting in fine burrs on the shaft. And unfortunately, they like lip seals for breakfast ...Have a good look at the shaft under the seal.
Keep in mind also, that the shaft moves along its axis when under way. The propeller moves the engine forward, so the part of the shaft actually under the lip part of the seal is a cm or more aft than can be gauged when moored.
As to replacing the seal in the water: you would be amazed at the massive column of water coming from the stern tube. Moreover, the new rubber is quite rigid in winter, and doesn't fit easily readily in many cases. Not to be recommended IMHO, unless planning an interior refit.

 

[SimonD]

I think there are two failure modes (how technical!) for these seals. First, they seem to harden with age. However, these takes a very long time - mine went nearly twenty years before needing replacement. Second, they can be damaged through overheating. The solution to the latter is obviously greasing. However, I also recommend more frequent burping. For some reason I cannot fathom, mine (new last year) seems to accumulate air whilst in the water. As the engine seacock is next to it, it's not difficult to remember to give the seal a squeeze at regular intervals.

Finally, I suggest that if it does leak, it does so when the shaft is turning. You don't so much get a drip as a fine spray!

 

[nedmin]

I am sorry to disagree but I wouldnt use the plastic tube to put in grease. In the Volvo instructions it tells one to cut off a corner of a plastic bag as I said. I would not want to push a plastic tube which obviously distorts the seal to a larger diameter, it is much better to use the corner of a bag and rotate the shaft to spread the grease.

 

[jerryat]

Yes, you are quite correct. Cutting the corner off a reasonably strong polythene bag is by far the best way. I say 'reasonably strong' because thin ones like sandwich bags distort too much under pressure and more often split.

 

[Blue Fox]

My seal was damaged late this season, because my gearbox had to come out. Apparently the mechanic moved the shaft backwards when he lifted out the gearbox. Five minutes running after things were put back made the seal leak like a sieve. Also when the engine wasn't running. Had to come out in a hurry!

 

[Heckler]

the red doofer is to protect the seal as you slide it along the shaft, the rest is correct, they shouldnt leak at all!! is the engine alignment OK?
Stu

 

[christopherc]

Hurrah!! It wasn't the stern gland after all (I thought there was a lot of water appearing from what seemed a dribble). The hot water tank pressure relief valve was doing its job as the hot water boiled due to thermostats set way too high. The drain appears just next to the stern gland. Adjusted the thermostats yesterday, and no more water! The gland does seem to drip a little, particularly when the engine idles and theres more vibration, but not a lot, hopefully greasing will prevent it degrading further since given what is said above, it should last a long time.

 

[dial-a-monkey]

There's an excellent photo of the inside of a Volvo Penta Stern Gland on vyv_cox?'s website
http://coxengineering.sharepoint.com/Pages/Sternglands.aspx

It's great to see how the thing looks on the inside and how it works! also liked the video of someone changing it afloat.

Does anyone know of the goal should be to try to get silicone grease into the rubber water-lubricated bearing? in the center of the gland? In ADDITION to helping with the dual sealing "lips" on the engine side of the gland.. Or is the water essential to cooling and grease in the bearing might block that process..??

Anyways just a thought..

 

[Plevier]

Does anyone know of the goal should be to try to get silicone grease into the rubber water-lubricated bearing? in the center of the gland? In ADDITION to helping with the dual sealing "lips" on the engine side of the gland.. Or is the water essential to cooling and grease in the bearing might block that process..??

Anyways just a thought..

Not silicone grease. I believe the Volvo grease is a lithium complex grease like this http://www.mobilindustrial.com/ind/english/products_greases_mobilgrease-xhp-220-series.aspx (I don't know if that's the actual one but it's certainly the same colour! This is the one KiwiProp supply for greasing their props too, I don't think you can tell them apart side by side.)

I fill a drinking straw with it (very easy from the Kiwi needle nosed grease gun or the nozzle of the tiny Volvo tube), flatten the end and slip it in under the edge of the seal for an inch or so, then squeeze the grease out of it while withdrawing it so it gets on both sides of both lips.

 

[KREW2]

I forgot to burp mine this year. I ran it for only half a mile and i noticed a small drip. I was told a short run like that should not cause it to drip, more grease was probably needed, and to make sure I got it down to the second lip.
The best way to do this is with a plastic drinking straw. I use the proper volvo grease for the job. Squeeze a good inch of grease into one end of the straw and flatten the end, pinch the gland and insert the flattened straw so the end is about 3cm in. With a finger, press the straw (behind the grease) onto the prop shaft and slide the finger it up to the gland. Keep the straw pressed to the shaft remove it and repeat as needed.
It works and stopped my drip straight away.

 

[Crowblack]

MacDonalds straws are best - - excuse for a Big Mac !

 

[superheat6k]

My last boat had a Volvo 'blackjack seal'. The inner sealing lips must face outward, so if you simply insert the shaft they face the wrong way and can allow the seal to drip. Found greasing the special applicator and simply sliding this in and out flaps the lips over to their correct position.