Vetus prop shaft seal - Lip seals

[nigel1]

I'm about to the replace Vetus prop shaft seal as it has developed a slight leak when the shaft is turning. Luckily there is a spare seal onboard, otherwise looking at over a £100 to buy a new one.
The seal consists of a bronze casting with two lip seals.

I'm thinking that once the seal has been replaced, I could remove the lip seals from the old housing and replace with new lip seals, and here is the issue.
The lip seals are marked as KC 30x47x7. A bit of googling indicates that KC refers to a lip seal which has no garter spring. They are available, but it seems they are not off the shelf, and the maker needs a minimum order of 150, which is not going to happen.

Question, rather than use the KC type as originally fitted, would a normal double lip seal with a stainless steel garter spring work as a replacement, I can't think of any reason why not, seems odd that Vetus used this obscure type of lip seal in the first place.
Cheers
Nigel

 

[vyv_cox]

I can only think that maybe the spring tension might cause a wear groove to form on the shaft. You could try taking the spring out? If it does not seal then put it back.

 

[superboots]

my vetus seal (very similar to photo ) has just started to leak so also looking for replacement (35mm shaft)

 

[nigel1]

I can only think that maybe the spring tension might cause a wear groove to form on the shaft. You could try taking the spring out? If it does not seal then put it back.

Hi Vyv,

I think if that was the case, then the use of the garter spring would be a cause of concern in any application using a rotary shaft seal.

 

[nigel1]

my vetus seal (very similar to photo ) has just started to leak so also looking for replacement (35mm shaft)

Ouch, replacement is about £100, might find slightly cheaper if you look around.
Vetus Flexible Stern Tube Shaft Seal Kit (35mm Dia)

 

[vyv_cox]

Hi Vyv,

I think if that was the case, then the use of the garter spring would be a cause of concern in any application using a rotary shaft seal.

But it is a particularly large diameter. Sliding speed must be quite considerable.

 

[nigel1]

After a lot of enquiries to various seal suppliers, Action Seals in Wallasey have said they can supply a minimum order of 5 seals at £6.30 each.
Seems a very good price, so I have made an order.
The MD of Action Seals tells me that KC type lip seals are designed to provide a low friction solution, which I believe is what Vyv was alluding to.

 

[Boater Sam]

Years ago I needed low friction lip seals for a rotating shaft with axial plunge. I bought standard seal and slightly stretched the stainless garter springs to reduce the friction. They worked fine.

 

[rotrax]

Years ago I needed low friction lip seals for a rotating shaft with axial plunge. I bought standard seal and slightly stretched the stainless garter springs to reduce the friction. They worked fine.

An elegant solution-a proper PBO fix!

 

[nigel1]

Well that did not go according to plan.
Changed out the seal yesteday, and it turns out that at some point in time, Vetus has changed the design of the seal.
The new one I put on contains two lips seals, the aft most one is a single lip seal, no spring, type VC 30-47-7. The forward one is a double lip seal, no spring, type KC 30-47-7.
The seal supplier who said they could get the KC type phoned me yesterday to say they had been let down by their supplier who had sent them the VC type. All not lost as I would need those in case I have to repalce the seals in the future, and they sent me some double lip seals as well, free of charge.

The old seal housing I took off looks similar to the newer type but only has one seal in the housing, its all rubber, no inner steel case, and 21mm in length. Looks like it has been glued into the bronze housing, only way I could remove it was to burn it out. The old type seal housing has an inner diameter of 43mm.