Shaft seal 25mm v 1 inch

[Wandering Star]

A daft question probably (most of mine are) but if my. prop shaft is 1” will a 25mm PSS shaft seal work? 1” = 25.4mm. I realise I should buy a 1” seal kit but they cost £300+ & I can get a 25mm kit for a song so thought I’d ask anyway!

 

[Bilgediver]

I would speak to Norris who sell them as maybe you will only need to swap a seal and not the complete housing to change shaft size and still save money.


PSS Shaft Seals & Spares

 

[vyv_cox]

Definitely not. The stainless steel rotating face is a very close fit with O-rings in internal grooves to prevent leakage into the boat.

However the good news is that you can buy just the stainless part. I bought a spare one after mine corroded.

 

[Tranona]

Yes, essential you measure it accurately at the point the rotating face will be positioned on he shaft. The 0.4mm difference is critical - 25mm won't go on a 1" shaft and a 1" on a 25mm will slip. Same with any seal or bearing going on a shaft.

 

[Bilgediver]

Yes, essential you measure it accurately at the point the rotating face will be positioned on he shaft. The 0.4mm difference is critical - 25mm won't go on a 1" shaft and a 1" on a 25mm will slip. Same with any seal or bearing going on a shaft.

Just find a friend with a lathe and soon fixed : )

 

[vyv_cox]

Just find a friend with a lathe and soon fixed : )

True enough but she would need to be pretty skilled to increase the depth of the internal O-ring grooves and not damage the two optically flat ends.

 

[Bilgediver]

True enough but she would need to be pretty skilled to increase the depth of the internal O-ring grooves and not damage the two optically flat ends.

Surprising what you can achieve when necessary! However a quick phone call to Mr Norris might get the 1" version ???? Still cheaper than a complete one.

 

[Tranona]

A daft question probably (most of mine are) but if my. prop shaft is 1” will a 25mm PSS shaft seal work? 1” = 25.4mm. I realise I should buy a 1” seal kit but they cost £300+ & I can get a 25mm kit for a song so thought I’d ask anyway!

Assuming the bellows are the correct size to fit your stern tube you might be able to buy just the rotor in 1". Almost certainly the rotor is the same size, just machined to take the 1" seals. Pop round to Lake Engineering and ask them. Or you could save yourself a lot of money and fit a Radice for little more than 1/3 of the price of a PSS. Just taken my stern tube housing into Lake to be machined to rake a Radice

 

[ean_p]

There is a good chance that the fixed face has different sized O rings for the two different shaft sizes. The difference is only 7/8 thou on the radius and might well be absorbed by changing the original O rings for ones with a 0.4mm reduced material diameter ( or there abouts). I would tend to suggest that a trial fit were you get them on the shaft without damage would tend to indicate that they were going to be OK as once positioned they never move again. But of course you may find failure once immersed. Who knows without trying.

 

[vyv_cox]

There is a good chance that the fixed face has different sized O rings for the two different shaft sizes. The difference is only 7/8 thou on the radius and might well be absorbed by changing the original O rings for ones with a 0.4mm increase ( or there abouts). It will I suppose depend upon whether the grooves in the fixed face are of a size to accommodate the increased O rings in their compressed state. I would tend to suggest that a trial fit were you get them on the shaft without damage would tend to indicate that they were going to be OK as once positioned they never move again. But of course you may find failure once immersed. Who knows without trying.

It is quite a struggle to get the inch seal on, the o rings are very tight.

 

[ean_p]

It is quite a struggle to get the inch seal on, the o rings are very tight.

Yes sorry Vyv. In my head I was going from 1" seal on to a 25mm shaft where as the OP is going the other way. The concept still possibly holds though in that if ( and it is an if) the Fixed face is common between both the 1" and the 25mm shaft and the variation is in the seal material diameters then by exchanging the original 25mm O ring seals for new 1" O ring seals (presumably 0.4mm larger in material diameter) then the fixed face might well fit and seal OK. The primary test would be to see if the bore in the fixed face would encompass a 1" shaft. If not then clearly the fixed faces are not common .

 

[Stemar]

Or you could save yourself a lot of money and fit a Radice for little more than 1/3 of the price of a PSS.

I wanted to fit one, but there was too much wear and scoring on my shaft where the Radice would seal, so I had to get the PSS, whose O rings sealed on an undamaged part of the shaft.

 

[Tranona]

Difference in price would have paid for a new shaft! But not running on the shaft in the location where shafts wear is a big selling point for the PSS - just for me that does not outweigh the downsides (as I see it).