Rebuilding raw water pump - seals

[PetiteFleur]

I am going to refurbish the original (leaking) Jabsco raw water pump and keep it as a spare. I've dismantled it and the shaft is scored slightly where the raw water side seal sits - which is what I expected. A new shaft is out of the question so I was just going to renew the seals as the SKF bearings appear to be fine - they are both RS type and are on the engine side so additionally lubricated by the engine oil and there is no play when assembled. I know I should renew the bearings as well but this will be a spare pump and I've spent enough already and it's the easy option!
The seals are 12x22x7 single lip seal with a stainless garter spring. However after a search I see you can get 12x22x6 seals which will mean that the lip will bear on a new part of the shaft. This seems to a good idea, there should be no problem fitting them - is this a good idea and has anyone else done this? Any recommended suppliers of seals with stainless springs - it's many years since I was buying bearings and seals.

 

[PaulRainbow]

As a spare pump it isn't a terrible idea, beats putting it in the skip.

The shaft on the pump on my last boat was worn, as you describe. It worked OK but the seals didn't last as long. I fitted double lipped seals and put them in backwards. The seal ran on a completely different part of the shaft and were absolutely fine, i changed them annually.

 

[RichardS]

As a spare pump it isn't a terrible idea, beats putting it in the skip.

The shaft on the pump on my last boat was worn, as you describe. It worked OK but the seals didn't last as long. I fitted double lipped seals and put them in backwards. The seal ran on a completely different part of the shaft and were absolutely fine, i changed them annually.

Putting 6mm seals rather than 7mm is a commonplace method of avoiding a new or refurbed shaft which I've done several times on boats and cars.

Reversing the seal so the lips face away from the liquid they are supposed to contain is not recommended and I've never tried it. It will render the seal less effective than intended but if that means 5 years life rather than 7 (or whatever) it might be a strategy of sorts, especially so if you decide to change them annually.

Richard

 

[bigwow]

There you go

http://www.actionseals.co.uk/contact-us.html

 

[Poignard]

Ok for a get-you-home spare. I have an old one as a ready-use spare. I've never needed to use it but if I did, it would only take a moment to replace the normal one with it.

 

[Big John]

I have always had very good service from these people. http://simplybearings.co.uk/shop/

 

[PaulRainbow]

Putting 6mm seals rather than 7mm is a commonplace method of avoiding a new or refurbed shaft which I've done several times on boats and cars.

Reversing the seal so the lips face away from the liquid they are supposed to contain is not recommended and I've never tried it. It will render the seal less effective than intended but if that means 5 years life rather than 7 (or whatever) it might be a strategy of sorts, especially so if you decide to change them annually.

Richard

That's the point of using the double lipped seal Richard, it's designed to seal from both directions. Using one moves the contact point about 6mm instead of 1mm. I actually ran mine for 2 or 3 years like it, changing annually and it was still working fine when i sold the boat.

 

[johnphilip]

Ok for a get-you-home spare. I have an old one as a ready-use spare. I've never needed to use it but if I did, it would only take a moment to replace the normal one with it.

Only a Moment???
Not with Volvo design input,
Before you are able to get at the forth bolt fixing the pump you have to block up to take the weight of the engine, remove the Starboard front engine mount and turn the air blue as you curse the Volvo design team.

 

[Poignard]

Only a Moment???
Not with Volvo design input,
Before you are able to get at the forth bolt fixing the pump you have to block up to take the weight of the engine, remove the Starboard front engine mount and turn the air blue as you curse the Volvo design team.

Blimey! Better get a BUKH. The pump is right at the front. Loosen two Jubilee clips, remove two bolts and out she comes.

 

[RichardS]

That's the point of using the double lipped seal Richard, it's designed to seal from both directions. Using one moves the contact point about 6mm instead of 1mm. I actually ran mine for 2 or 3 years like it, changing annually and it was still working fine when i sold the boat.

Ah I see. Apologies Paul. I've never seen a double-lipped seal so I was visualising the two lips facing the same direction when they obviously both face outwards. That's clever!

Richard

 

[smithy]

Can you get a repair sleeve onto the shaft, google "speedi sleeve"

 

[Ruffles]

When I changed the seals some years ago there was a worrying brown ring on the shaft. On closer examination it was apparent it was actually proud of the surface. 10 seconds with the finest wet and dry and it disappeared completely. It was a combination of salts and surface rust. Worth checking.

 

[rogerthebodger]

That's the point of using the double lipped seal Richard, it's designed to seal from both directions. Using one moves the contact point about 6mm instead of 1mm. I actually ran mine for 2 or 3 years like it, changing annually and it was still working fine when i sold the boat.

Is this what you mean by double lipped seal

or this

The first is a single lip seal with an added dust lip.

The second is a bidirectional double lip seal that can seal both the oil side ans water side.

Dont know if these are available in the small sizes needed for Jabsco raw water pumps

 

[PaulRainbow]

2nd Roger. My pump only needed to keep the water in, there was an air gap between the water seal and the engine. So fitting the double seal version "backwards" moved the contact point almost the width of the seal. My seals were about the 7mm being discussed here.

 

[PetiteFleur]

Blimey! Better get a BUKH. The pump is right at the front. Loosen two Jubilee clips, remove two bolts and out she comes.

When I was researching my new engine I rejected some makes because the pump was so awkward to get at in a hurry, eventually settled on the Beta as it's at the front, small nuts are a bit fiddly but doable, and the impellor is easy to change, but I will replace the silly M4 screws with M4 stainless knurled thumb screws soon(obtainable on ebay).

 

[PetiteFleur]

Thanks everyone - I've now ordered 6mm wide Viton seals with stainless garter springs, double lipped, from Lancashire Seals on ebay.

 

[Ruffles]

I used these


12x22x7mm TC / R23 Double Lip Viton Rubber Metric Rotary Shaft Oil Seal with Garter Spring

http://simplybearings.co.uk/shop/Seals-All-Oil-Seals/c19_4463/p70221/12x22x7mm-TC-/-R23-Double-Lip-Viton-Rubber-Metric-Rotary-Shaft-Oil-Seal-with-Garter-Spring/product_info.html

 

[ghostlymoron]

Will the thumb screws exert enough pressure to compress a paper gasquet? I was told not. I subsequently got a friend with a lathe to machine a shallow slot for an O-ring to convert to a DIY speedsealer.

When I was researching my new engine I rejected some makes because the pump was so awkward to get at in a hurry, eventually settled on the Beta as it's at the front, small nuts are a bit fiddly but doable, and the impellor is easy to change, but I will replace the silly M4 screws with M4 stainless knurled thumb screws soon(obtainable on ebay).

 

[PetiteFleur]

Will the thumb screws exert enough pressure to compress a paper gasquet? I was told not. I subsequently got a friend with a lathe to machine a shallow slot for an O-ring to convert to a DIY speedsealer.

This Johnson pump and the earlier Jabsco had an 'O' ring seal so was fine.

 

[lw395]

When I changed the seals some years ago there was a worrying brown ring on the shaft. On closer examination it was apparent it was actually proud of the surface. 10 seconds with the finest wet and dry and it disappeared completely. It was a combination of salts and surface rust. Worth checking.

Similar here.
I polished the shaft with wet and dry and Solvol Autosol.
I ended up with a slightly grooved shaft, but it was a smooth polished groove and the seal still sealed on it and lasted until I sold the boat a few years later.
An 8mm seal will seal on a 7.9mm shaft. If it's smooth.

I think it's the pitting and roughness of a typical worn shaft which quickly wears the new seal. Or if it's formed a sharp edge which actually cuts the seal as it rotates.