Water lubricated shaft seal

[ArgoNot]

I've searched previous posts but without success so, can anyone explain how a water lubricated shaft seal works?
When I bought my boat last year I 'burped' the seal as described by the vendor. This year when she went back in the water I did the same thing but could not get any water out around the rubber boot. I'd like to understand how these things work and would be glad if someone could explain them, or point me to a diagram on-line.
I've tried a 'Google' too but without much luck.
Over to you, forumites.

 

[aztec]

two ways, by passing water down the tube to lubricat it. and by allowing water to surround the bearing, that's why you need to "burp" it.

you may find that your tube is full of grease, that's why you can't get any water out. i know that one of my boats has a tube that's very well greased.

have a look here http://www.lakesterngear.co.uk/

sorry can't remember the markup thing.

regards, steve.

 

[nedmin]

if its the volvo type,its sounds like it is if you are squeezing it, you have the outer surround,this is jubilee clipped to the stationary tube, at the narrow end there are approx. 3 lip seals that grip the prop.shaft,inboard of these is a cutlass type rubber bearing that bears on the prop.shaft, this allows the lip seals to move exactly the same up and down as the prop. shaft,so it doesnt leak past the lip seals.The lip seals need a water proof grease,this is done by cutting off the corner of a poly.bag put in approx 1sq.cm grease in the bag,push the corner under the seal as far as poss.and squeeze the grease in.boat really needs to be out the water but you could try if in.when you squeeze seal water should come out,are you squeezing at opposite sides about 1/2 an inch in?from gearbox end?

 

[ArgoNot]

Thank you, both aztec and nedmin.

I don't think the PSS type shown on aztec's link is what I have. I don't recall there being a bellows on mine, but it's not the most accessible component and I could have missed that. The boot has a slight taper towards the gearbox and has no jubilee clips other than at the sterntube. But I shall make sure next time I'm on the boat.

As to greasing the thing. I did that before launch this year, injecting about 1cc of waterproof grease in under the lip of the seal at the gearbox end.

To 'burp', when I reach in and grip the rubber boot I try for a location along its length where I can feel some 'give' so that when I squeeze, as though to grip the boot more tightly, I feel as though I might get some sort of pumping action. There's not much 'give' though.

I did get some grease out when I did it at the weekend and it might just be that it's full of grease as aztec suggests.

 

[nedmin]

I am sure your seal is the volvo type from what you say.The three lip seals are approx. 1/4-1/2-3/4 inches in from the start of the taper ie gear/box end. You need to squeeze here to make the lip seals go oval and let water out.if you get an airlock,. the cutlass bearing wont get any lubrication.I cannot think that grease is stopping the water coming thro.

 

[paulskent]

Have gone through the same process recently assuming that this is a volvo unit..

With mine you have to squeeze (yes there is not much give) and exert downward pressure at the same time. This results in a small dribble coming from the bottom lip of the gland.

This is as per the volvo manual instructions.. There was a link to the manual posted in the forum in the last couple of months..

 

[jerryat]

Hi Nedmin,

There are only two 'seals' on the Volvo shaft seal. I've just fitted a new one. Logical when you think about it - the outer one is water lubricated (hence the need to 'burp'!) and the inner is waterproof grease lubricated as you describe.

Cheers Jerry

 

[jerryat]

Hi Paul,

Sorry to disagree, but you are advised to squeeze and pull upwards at the same time when 'burping'!! The reason is that this allows the water to escape at the top of the seal and therefore ensure that the whole seal is lubricated.

Cheers Jerry

 

[philip_stevens]

From the Volvo (Sweden) site - it is known as......

Rubber packing box
42.36742.367

Moulded packing box for effective lubrication/sealing. Simple, time saving installation and compact size. Minimal maintenance work – grease every 200 hours or once a year. The packing box is specifically dimensioned for Volvo Penta propeller shafts and sleeves. For effective lubrication it is essential that the packing box bearings are water-lubricated at all speeds. Supplied complete with installation tools and grease tube.

Pos no. Part no. Shaft mm A mm B mm Ext. dia. shaft sleeve mm 1)
42.367 828527 40 36 82 60
42.367 828526 35 36 82 54
42.367 828422 30 36 72 48
42.367 828254 25 36 66 42


1) Diameter tolerance +0.5 –0.3 mm. The distance between bearing points must not exceed 1500 mm.


Start at -
http://www.volvo.com/volvopenta/global/en-gb/

http://www.volvo.com/volvopenta/global/en-gb/partsservice/

http://www.volvo.com/volvopenta/global/e...ntroduction.htm
(go to the Web Accessory Catalogue - enter British English [or whatever language you want]

A pop-up window appears - search by name, part no. or pos no.

Enter Rubber packing box - search
search results (1 hits)
1. Rubber packing box
Accessory Catalogue » Engine accessories » Transmission system » Propeller shaft system » Rubber packing box

hover over and click

another pop-up window
......and there you are.

On your way to this page, there is reference to the correct grease - that was how I was able to find the seal in the first place!

Not easy to find,

"The grease is solid and water-resistant, for use in rubber packing boxes and for the teeth and shafts of folding propellers.

Viscosity: NLGI 2

Pos no. Part no. Quantity Pack
18.17 828250 27 g Tube"

 

[jerryat]

Hi Phillip,

Wow!!! The Complete Volvo Shaft Seal info! Purely out of interest, I have used Blakes seacock grease in my seal (just changed after exactly 21 years!!) and will be using the same in the new one when the supplied grease runs out.

The old seal was, incidentally, still totally watertight and I only changed it 'cos I was doing a major refit including stripping/rebuilding the engine, changing the Cutless bearing etc. I think they a marvellous solution to shaft sealing and am amazed that we still get posts on this forum from guys/gals using the old stuffing gland type and putting up with drips into the boat. Bit like using an abacus instead of a computer!! /forums/images/graemlins/wink.gif /forums/images/graemlins/smile.gif

Cheers Jerry

 

[ashanta]

You should have a plastic sleeve that you keep inside the inner edge of the seal during your layup. You remove this and grease as previously described. The burping is done at the edge (gearbox end) and not further along where it's more pliable. You have to squeeze reasonably hard on the edge and the water should then trickle through.
I hope this helps.

regards.

Peter.

 

[paulskent]

I was having problems getting the seal to vent until I found the following in the manual. If you have a look at page 2 it clearly indicates that downward pressure is required.

Is your suggestion that it should read upwards pressure based on experience or something you have heard from Volvo ??

Shaft seal manual

 

[ArgoNot]

Thank you all for your help and advice. Following Philip's link it's definitely a Volvo type on my boat, but from ashanta's description and paulskent's link I think I've been squeezing it incorrectly.

I don't think I have the plastic sleeve ashanta mentions, though it is possible if is lying unrecognised and unregarded in the engine spares box. Next visit to the boat and I shall investigate all of these things.

Again, many thanks all.

 

[jerryat]

Hi Paul,

No, nothing in writing, just that was the advice given to me by the Volvo agent from whom I bought the thing! Seemed eminently sensible to me and, as I mentioned, has worked for me for the last 17 years (and was the original 1984 one fitted by Westerly) with virtually no wear.

Oddly enough, I've just got back from my boat on the club moorings and, chatting to three of my friends who also have this type of seal, I found that all bleed theirs the same as me, though for no particular reason! /forums/images/graemlins/crazy.gif

Ah well, looking at the thing about an hour ago, and particularly at the angle of the shaft, the difference in water level (from top to bottom) is tiny, so I guess it's not critical. It may be that Volvo expect everyone to squeeze the grease in at the top (certainly the most convenient place) so suggest pushing down to reduce the chance of the grease being pushed out by the water.

I get over that potential problem by turning the shaft a few times manually, prior to launch, to distribute the grease round the seal, then bleed as I described.

I haven't downloaded the manual you linked to (I've only got dial-up and it'll take too long) but there was just a two sided installation sheet in the box with the 'new ' one (bought about 8 years ago!) that I've just fitted. Perhaps the march of time has 'improved' things!! /forums/images/graemlins/crazy.gif

Cheers Jerry

 

[philip_stevens]

I have always vented my Volvo shaft seal, the same way as you, by pinching the top and allowing air and a drop of water to escape at the top - but....

I have just read the instructions sheet, and find that I (like you and many others) have, according to the instructions, been venting it wrongly!!

Item 11 on the instruction leaflet.
After launching:

11. Vent the tubular sleeve as follows:
The propeller shaft seal which is water-cooled should be vented after launching by compressing it at the lip seal at the same time as it is pressed towards the propeller shaft (fig F). A gap is formed between the shaft and seal (fig E) when it is compressed. When water forces its way out from the gap, the seal is air-vented.

The fig E shows an arrow "pouring" from the bottom of the shaft/seal.

Well....if all else fails, read the instructions!! After ten years, and two boats, both with the Volvo shaft seal, I now know the correct way to vent it. You live and learn.

 

[TNT]

shaft seal lube

Hi all interesting reading, bought out boat two years ago and this was the first time I had come accross this type of seal. I have vented it but was not aware of the waterproof grease requirement, noticed there was a nylon insertion sleeve required to grease, anyone have a description of it so I can have a search in the parts kit and see if its there. Just out of interest does this slide between the shaft and the seal?, if so soes this not damage, or potentially damage the seal itself?

 

[alahol2]

11. Vent the tubular sleeve as follows:
The propeller shaft seal which is water-cooled should be vented after launching by compressing it at the lip seal at the same time as it is pressed towards the propeller shaft (fig F). A gap is formed between the shaft and seal (fig E) when it is compressed. When water forces its way out from the gap, the seal is air-vented.[/i]

The fig E shows an arrow "pouring" from the bottom of the shaft/seal.

I haven't got one of these so no real interest but since when did one try to vent air from the bottom of a container?

 

[Vara]

Hi all interesting reading, bought out boat two years ago and this was the first time I had come accross this type of seal. I have vented it but was not aware of the waterproof grease requirement, noticed there was a nylon insertion sleeve required to grease, anyone have a description of it so I can have a search in the parts kit and see if its there. Just out of interest does this slide between the shaft and the seal?, if so soes this not damage, or potentially damage the seal itself?

Drinking straws from McDonalds (burger sellers) work very well for this, introduce some grease to straw, flatten end, slide into seal, squeeze grease in.

Not my idea, picked up on the forum.

I'm sure Burgerking or even Wimpy straws would work just as well.

Just done this and it does make it easy.

 

[Tranona]

Hi all interesting reading, bought out boat two years ago and this was the first time I had come accross this type of seal. I have vented it but was not aware of the waterproof grease requirement, noticed there was a nylon insertion sleeve required to grease, anyone have a description of it so I can have a search in the parts kit and see if its there. Just out of interest does this slide between the shaft and the seal?, if so soes this not damage, or potentially damage the seal itself?

No. you do not need the sleeve. That is only needed when you first instal the seal to compress the lips of the seals so they don't get damaged when sliding down the shaft.

To grease, put about 20mm in the end of a drinking straw (McDonalds is best but you need a paper bag over your head when you go in there to acquire one) flatten the end to push between the seal and the shaft and squeeze. Once a year job. Don't forget to burp as described above (I get the dribble out of the bottom) - although if it does run dry you soon know about it unless you are deaf!