Sadler 29 Volvo shaft seal size

[Wandering Star]

Would anyone know the correct Volvo shaft seal to buy for my Sadler 29? I’m confident the propshaft is 1” and looking at it I’d guess the stern tube is 1 3/8” but can’t measure it exactly as I’m frightened to remove the old seal before Ive got the new seal to hand! Although the old seal looks perfectly good I’d prefer to replace it as the boats been ashore for many many years!

 

[Blueboatman]

Use a £15 digital vernier calliper or micrometer?

25mm or 25.4 imperial are quite difficult to differentiate. It might even have had the wrong one fitted inadvertently I suppose.

And feel/ measure for wear when you slide the old Volvo seal forwards

 

[johnalison]

I have an idea that I ended up having to fit a metric seal to the 1” shaft, but this was thirty odd years ago, so don’t take my word as advice.

 

[Wandering Star]

I have an idea that I ended up having to fit a metric seal to the 1” shaft, but this was thirty odd years ago, so don’t take my word as advice.

From another thread, fairly sure I can get a seal to fit a 1” imperial shaft, it’s the outer stern tube end I’m not sure about until I measure it.

 

[snowbird30ds]

I would hazard a guess that 0.4mm on a smooth shaft is sod all to a volvo type seal, the lips are pretty long and should take that up no problem.
Different matter on cutless bearings though so good measures are worth having.

 

[Tranona]

From another thread, fairly sure I can get a seal to fit a 1” imperial shaft, it’s the outer stern tube end I’m not sure about until I measure it.

If it is a 1" then there is only one size tube 42mm. If it is 25mm there are 2 sizes 39 and 42mm. Pretty sure it will be 122 but critical to get it right because the 2 are definitely not interchangeable - that 0.4mm is critical.

You get a Radice seal from Lake Engineering in Hamworthy p35 in the catalogue here lakesterngear.co.uk/catalogue.pdf

 

[Malish]

I would hazard a guess that 0.4mm on a smooth shaft is sod all to a volvo type seal, the lips are pretty long and should take that up no problem.
Different matter on cutless bearings though so good measures are worth having.

not sure about that plenty of discussion on here in the past, makes you wonder why Volvo offer both options...

To the OP, a cheap vernier gauge will confirm which is the correct choice. Tbh the bigger question is at the aft end. Determining the correct size of your stern tube is essential and you may have to devise a spacer such as a short length of silicone tube and a dollop of sikaflex if your stern tube does not align with a 'Volvo' diameter.

 

[Tranona]

not sure about that plenty of discussion on here in the past, makes you wonder why Volvo offer both options...

To the OP, a cheap vernier gauge will confirm which is the correct choice. Tbh the bigger question is at the aft end. Determining the correct size of your stern tube is essential and you may have to devise a spacer such as a short length of silicone tube and a dollop of sikaflex if your stern tube does not align with a 'Volvo' diameter.

The boat already has a Volvo seal fitted so stern tube is not a problem.

You are right about getting the correct size. It is not the lip seals that are critical bits but the water lubricated fluted rubber bearing that makes up most of the length of the fitting. A 1" on 25mm will leak and a 25mm on a 1" the shaft will barely turn. Guess how I know that.

 

[Plum]

I would hazard a guess that 0.4mm on a smooth shaft is sod all to a volvo type seal, the lips are pretty long and should take that up no problem.
Different matter on cutless bearings though so good measures are worth having.

As already said by Tranona, that 0.4mm makes a big difference. Behind the two lip seals is an integral cutless type rubber fluted bearing that has to be the correct size.
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