Oil drip from stern gland -should I be worried?

[dunkelly]

Hi , my boat is fitted with a hilyard shaft seal on an 1 1/4 " shaft and has started to slowly drip oil , although I've been checking the oil reservoir for the season and there appears to be no appreciable change in the level ? I've started looking at replacement which I would plan to do in the spring .
2 questions .
1 . Is it ok to continue to use the boat and is there anything I can tighten to reduce the drip even though it seems very slow .
And.
2 . Has anybody fitted a new shaft seal and can offer any advice .
The boat is a macwester 27 1992 vintage .
Many thanks for any help

 

[Tranona]

Should be OK until end of season. For replacement there is a wide choice. The simplest is the Volvo/Radice type but it depends on the size of your exposed stern tube as the range of sizes is limited. Otherwise a Tides Marine with lip seals of a PSS with face seals which have much more choice in sizes but also much more expensive. Surprised you have a 1 1/4" shaft, normally a 1" or 25mm for engines of the size typically fitted to your boat. Important to measure accurately before ordering replacement.

 

[Metalicmike]

Its working, if you have to top up the oil regularly then look at seal replacement but when its in the water the water pressure will reduce the oil leakage and while ever the tank is topped up the oil pressure will stop water ingress.

 

[dunkelly]

Should be OK until end of season. For replacement there is a wide choice. The simplest is the Volvo/Radice type but it depends on the size of your exposed stern tube as the range of sizes is limited. Otherwise a Tides Marine with lip seals of a PSS with face seals which have much more choice in sizes but also much more expensive. Surprised you have a 1 1/4" shaft, normally a 1" or 25mm for engines of the size typically fitted to your boat. Important to measure accurately before ordering replacement.

I will re check my dims . I put a new stern tube in 3 years ago and that's what I thought it was but easy to measure. Many thanks

 

[dunkelly]

Its working, if you have to top up the oil regularly then look at seal replacement but when its in the water the water pressure will reduce the oil leakage and while ever the tank is topped up the oil pressure will stop water ingress.

Interestingly I've never thought to wipe underneath before so it may always have been like this hence not appearing to use oil . What alarmed me initially was water in the bilge but I guess it's possible the water is entering from somewhere else as I tested it and it's not saltwater so a possible cockpit lid or something leaking . I'll keep monitoring before I decide what if anything needs doing ..

 

[PCUK]

If I recall, the Halyard seal uses standard lip seals so should be an easy refurb'.

 

[vyv_cox]

There is quite a lot of information about Halyards seals here Stern glands

As PCUK says, standard automotive seals are used, cheap and easy to replace

 

[rogerthebodger]

There is quite a lot of information about Halyards seals here Stern glands

As PCUK says, standard automotive seals are used, cheap and easy to replace

The spring needs to be stainless steel but if the existing spring is in good order the spring in the new seal can be changed with the old one as I have done in the past

 

[vyv_cox]

The spring needs to be stainless steel but if the existing spring is in good order the spring in the new seal can be changed with the old one as I have done in the past

In theory two springs face the oil, in which case carbon steel should be ok. Theory and practice do not always coincide!

 

[Metalicmike]

Talking about oil seals, I had to replace the seal in the water pump and was surprised to see that the spring was carbon steel and had collapsed. I managed to find stainless on the internet and ordered the replacement plus spares.

 

[rogerthebodger]

The spring normally faces the liquid that you are sealing against

In the case of a water pump its faces the water side and as in a prop shaft seal its th same but the seal the OP quoted has oil in some cavity.

Vyv mentioned 2 springs so the seal could be a double lip seal with 2 springs and can seal from both sides.

The alternative could 2 separate lip seals set back-to-back as in the Jabsco raw water pump

My own stern seal is a PSS so are not used to the oil filled stern seal

 

[dunkelly]

Thanks all for the advice . I hadn't even considered that it may be refurbished , but it would be great if it could as this years refit budget has been severely cut by the loss of the wfa .

 

[vyv_cox]

The spring normally faces the liquid that you are sealing against

In the case of a water pump its faces the water side and as in a prop shaft seal its th same but the seal the OP quoted has oil in some cavity.

Vyv mentioned 2 springs so the seal could be a double lip seal with 2 springs and can seal from both sides.

The alternative could 2 separate lip seals set back-to-back as in the Jabsco raw water pump

My own stern seal is a PSS so are not used to the oil filled stern seal

There may be variations but the one I am familiar with has two seals containing and facing the oil and a third facing the water in the stern tube.

My Yanmar 3GM water pump originally had a brass-looking spring, I think a beryllium-copper alloy. When it failed I was advised that Volvo equivalent seal was identical but with a stainless steel spring. I bought a couple of them. I later bought a Yanmar replacement pump that came with a stainless spring.

 

[rogerthebodger]

There may be variations but the one I am familiar with has two seals containing and facing the oil and a third facing the water in the stern tube.

My Yanmar 3GM water pump originally had a brass-looking spring, I think a beryllium-copper alloy. When it failed I was advised that Volvo equivalent seal was identical but with a stainless steel spring. I bought a couple of them. I later bought a Yanmar replacement pump that came with a stainless spring.

Yes, the original lip seal for water did have beryllium-copper springs but at some point, it changes to stainless steel

Having designed many sealing set ups over the years it was in the seal design spec as I remember correctly

Wife used to work for a seal manufacturer at some point, so she also knew about the different spring arrangements