Leaking Volvo raw water pump following refurb

[Bertie1972]

I refurbed my Volvo Penta raw water pump with a shaft, bearing & seals kit from FYB.

Everything went on and in as it should. However, on starting the engine, a lot of water came out of the weep holes behind the impeller chamber. On removing the cover, I found the rubber ring (9 on the diagram) had made its way through the outer seal (10) and was now damaged & in the impeller chamber.

I disassembled & reassembled everything as per the diagram (or so I thought).
Now I’m reluctant to simply replace the O-ring and impeller-side seal and try again, in the hope that it won’t happen again (not least because the O-ring was £16).

Has anyone experienced this, or have an idea what might have happened?

 

[Ammonite]

I strongly suspect you've put the pump back together incorrectly. For example, you put the seal(s) in wrong way around or left out the spacer. The garter spring on the seal needs to face the medium its sealing and if its not the O ring could get sucked past the seal. That O ring isn't really sealing anything. It's a thrower ring that ensures any leaks from the seals exit the telltale hole rather than track along the shaft. Just replace it with a nitrile (nbr) one the same size. It will cost pennies. If you haven't already done so take a look at a rebuild video on YouTube. There are several. I'm assuming you bought the right kit as there are early and later model kits available. What engine/year/pump model is it?

 

[VicS]

I refurbed my Volvo Penta raw water pump with a shaft, bearing & seals kit from FYB.
Everything went on and in as it should. However, on starting the engine, a lot of water came out of the weep holes behind the impeller chamber. On removing the cover, I found the rubber ring (9 on the diagram) had made its way through the outer seal (10) and was now damaged & in the impeller chamber.
I disassembled & reassembled everything as per the diagram (or so I thought).
Now I’m reluctant to simply replace the O-ring and impeller-side seal and try again, in the hope that it won’t happen again (not least because the O-ring was £16).

Has anyone experienced this, or have an idea what might have happened?

How much ?
Should be under £1, but what engine are we talking about ?

 

[Bertie1972]

I strongly suspect you've put the pump back together incorrectly. For example, you put the seal(s) in wrong way around or left out the spacer. The garter spring on the seal needs to face the medium its sealing and if its not the O ring could get sucked past the seal. That O ring isn't really sealing anything. It's a thrower ring that ensures any leaks from the seals exit the telltale hole rather than track along the shaft. Just replace it with a nitrile (nbr) one the same size. It will cost pennies. If you haven't already done so take a look at a rebuild video on YouTube. There are several. I'm assuming you bought the right kit as there are early and later model kits available. What engine/year/pump model is it?

It's a 2006 D120. I'd watched owner workshop videos, plus checked the kit contents were identical to original items.
Nonetheless as you suggest, it does look like something's incorrect. The outer seal was definitely the correct way round, the water leaked in one direction, while the O-ring passed the opposite way. I suppose the leakage took place as the ring made its way through the seal.
The only thing I can think, is that the inner seal may be set a little to far in the pump body, and it and the spacer are perhaps pushing the ring against the outer seal.
Thanks for the suggestion about a pattern nitrile seal, I'll have one more go with a new ring & if it happens again, will take it apart and check distance between the two seals

 

[Blueboatman]

My two bobs worth
Once you’ve dismantled and checked the component assembly order is in fact correct:

If you have access to a micrometer just check that the shaft isn’t ridged ( you can probably feel it under your thumb nail too). Because it might need spinning in an electric drill with some fine emery paper held lightly against it, to make it all smooth again.

And ( next time) take the old seal to a local bearing shop if you have time.
It will be a standard item and sold without marine mark up.
(There are old threads on this if you search the forum index)

 

[Ammonite]

And ( next time) take the old seal to a local bearing shop if you have time.
It will be a standard item and sold without marine mark up.
(There are old threads on this if you search the forum index)

Or online...but make sure you order one with a stainless spring for the raw water side, or go with a Viton one as these come with stainless springs as standard.

 

[Blueboatman]

Or online...but make sure you order one with a stainless spring for the raw water side, or go with a Viton one as these come with stainless springs as standard.

Even better