Stern Gland - what is it?

[down...2 greens]

Hi all,

I've just noticed that my stern gland has been leaking oil (and also seems to have allowed a bit of water ingress, judging by the little puddle visible in the photo). I haven't had time to confirm the source of the oil leak, but presumably the lip seal would be the first suspect. So, can anyone help me identify what type of gland this is - and how to track down the right replacement seal, if that's what it needs?

All suggestions appreciated, as always.

 

[burgundyben]

Many of the boats built by Fairey Marine had stern glands like that, they usually have a pair of lip seals in them, standarnd off the shelf seals, identified by numbering on the side of the seal.

You should specify stainless steel springs.

 

[superheat6k]

I would suggest replacing it with something from the 21st century - PSS, Tides, etc.

 

[PlankWalker]

When you replace it double up on those Jubily clips.
failure of any one at the moment could be catastrophic.

 

[down...2 greens]

Thanks guys. I'd prefer not to replace the whole thing just because of the effort and cost - plus the gland has performed perfectly for the last few years until this recent issue, so if a seal replacement does the trick then I'd be happy.

By the way, in case it helps with identification, the upper flexible pipe in the picture is the oil feed - the one at the side just vents to atmosphere. It's just a little VP2001 engine.

 

[Tranona]

You will have to take it off to replace the seals anyway so a good opportunity to replace it with a Volvo type seal such as this elicheradice.com/product-line/axial-seal-rmta-rtmo-type/ cist under £100. Only constraint is that the external diameter of the stern tube has to be 43mm for a 1" shaft.

Oil filled lip seals were in vogue 30 tears or so ago, but fell out as other better and more cost effective products came on the market. Nothing wring with them, just expensive and overengineered for the job.

 

[vyv_cox]

The beauty of this type of gland is that the seals are widely available and cheap. Once you know the size and maybe part number any automotive supplier will sell you replacements, or online from Simply Bearings. There are several shown on my website under 'Stern Gear'.

 

[down...2 greens]

Thanks Vyv, I had a look - some great info there as always. Given that the gland performed flawlessly until very recently my instinct is still to just replace the seals (assuming that's what the problem is), although Tranona's idea is worth thinking about too.

The prop shaft is 1" but I have no idea of the dimensions of the seal itself. Is the only option to haul out, remove the old seals and then try to find something to match, or is there a way to figure out what I need beforehand and order the parts in advance?

 

[Bodach na mara]

I don't think that the upper pipe is an oil feed, more likely water. What the other is would be to dump the water somewhere, possibly through a skin fitting in the topsides. Their function is to ensure that the seals are kept wet to lubricate them. Personally I have never seen an oil-fed gland. More usually there is a grease supply but not to a gland that relies on rubber lip seals.

 

[Tranona]

Definitely oil filled with the oil between the 2 seals. Have not seen that particular design but they were very popular in Scandinavia - Bukh used to make them and Vetus still make similar, if a little more sophisticated. The upper pipe leads from a reservoir and the lower is a vent to avoid air bubbles forming.

The OP will only know how the seals are held in when he takes it apart, but they will almost certainly be standard seals with a reference number moulded in.

 

[Boater Sam]

Can you not measure the seal that you can see? A digital caliper will measure the shaft, 1" or 25mm and the OD of the seal can be measured by measuring the housing diameter and deducting twice the wall thickness.

In fact, if you clean it up you may be able to read the seal size directly, its always on the backside of the seal, usually OD, ID, and thickness.
I bet both seals are the same size. You need stainless garter springs in them and if its oil filled, nitrile rubber.

 

[vyv_cox]

Can you not measure the seal that you can see? A digital caliper will measure the shaft, 1" or 25mm and the OD of the seal can be measured by measuring the housing diameter and deducting twice the wall thickness.

In fact, if you clean it up you may be able to read the seal size directly, its always on the backside of the seal, usually OD, ID, and thickness.
I bet both seals are the same size. You need stainless garter springs in them and if its oil filled, nitrile rubber.

Yes it looks like the lip of the seal runs on the shaft. In some designs, e.g. Halyard, there is a sleeve but I cannot see one here. As you say, should be easy to measure the OD. Check in both metric and imperial, as sometimes a strange metric dimension converts to a logical inch one

 

[down...2 greens]

Good ideas, thanks. I'll see what I can figure out when I get time to look properly. In the meantime I topped up the oil reservoir again - it's definitely leaking (into the bilge) so will need attention asap I suppose ?

 

[roaringgirl]

Good ideas, thanks. I'll see what I can figure out when I get time to look properly. In the meantime I topped up the oil reservoir again - it's definitely leaking (into the bilge) so will need attention asap I suppose ?

You'll have to take out the propshaft to change the seals. So you're going to have to haul out or dry out at the very least. That being the case, you may as well haul out, remove the old seals and take them to a bearing shop to get replacements.

 

[down...2 greens]

Thanks, that sounds like a plan. Final silly question: does it matter much what grade of oil I refill it with? Not knowing the type of seal I can't just google the manual

 

[Tranona]

Don't think it really matters, but when I was involved with such seals 30 years ago we used engine oil. similar seals are used in saildrive shafts and use engine oil.

 

[roaringgirl]

That sounds like a question for the bearing shop.

 

[scottie]

Don't think it really matters, but when I was involved with such seals 30 years ago we used engine oil. similar seals are used in saildrive shafts and use engine oil.

Yes the oil is a special formula or was 20 years ago as I recall possibly water soluble
I think that there was a grease filled version

Whatever you do replace the hose with the proper grade from portsmere rubber who may be of help in specifying the oil used

 

[vyv_cox]

Thanks, that sounds like a plan. Final silly question: does it matter much what grade of oil I refill it with? Not knowing the type of seal I can't just google the manual

My website says a 10w-30 multigrade, 30 monograde or ATF for Halyard seals. I see no reason why yours should be any different. Little reason to use an ATF unless you use it elsewhere so I would go for the multigrade. If your engine takes 15w-40 I would not be concerned at the slight increase in cold viscosity.

 

[down...2 greens]

That's great, thanks everyone - very helpful as always!