Leaking waterpump

[Andrew_B]

I have just taken the waterpump off my Yanmar 3GM as it has started to leak from one of the small holes just behind the pulley.
I've taken off the pulley which reveals a bearing held in by a circlip.I have also taken out the impeller.
If I remove the circlip will the shaft and bearing simply knock out or is it a job for the Yanmar man.
Also if it does knock out is it usually bearing failure that causes these pumps to leak or is there some kind of seal inbetween the impeller housing and bearing which wears.
Any help would be much appreciated as I am now stuck to the dock.

Andrew

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[Gunfleet]

Andrew, I've had this problem on a 1GM and I think you'll find a leak from the back of the pump is a job for Mr Yanmar. Make sure you're sitting down when they tell you the price. By the way this problem is a classic example of why people should always shut all their seacocks when leaving the boat. Imagine (I can) what would happen if you left the raw water cock open, went away for a week and the pump started leaking half way through? Horrible to contemplate. But I bet we've all forgotten and left the raw water cock open from time to time.

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[sjohn_gibson]

I do not know your pump but I am sure with a little mechanical know how you could overhaul it. I have just finished overhauling my engine (Mercedes 636) fresh water pump and recently ovehauled my Jabasco salt water pump.

These pumps contain a spring loaded mechanical seal that prevents the water escaping. Leaks from the drain hole means this seal needs replacing. These seals are expensive - £30 + vat - and come in 2 parts: a static face that fits into the body of the pump and a matching carbon face mounted in a rubber/metal assembly that fits onto the shaft. This assembly rotates with the shaft and has an integral spring to keep the carbon face pressed against the static half of the seal.

I usually replace the roller bearings at the same time.

In my case the the shaft was cordoed where the seal was located. However, I have an obliging friend who turned up a new one for me.

There is a small firm (Bearings UK, St Neots Cambs) near me who specialise in supplying bearings. They are extremely helpful and have never failed to find me a suitable commercial seal or bearing. Thus avoiding boat spare prices.

Yours
John

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[Andrew_B]

Problem solved

Thanks for the replies.
In the meantime I removed the circlip and knocked out the shaft to find 2 sets of roller bearings and an ordinary rubber shaft seal.
One bearing was no good but the other looks OK.
I carry a few spare bearings an with a bit of trial and error I found the spare I carry for my Shurflo fresh water pump fits perfect.
With the old bearing pulled off and the new one pushed on all I need now is a shaft seal from the shop in the morning and I am in business.

Thanks anyway


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[Johnjo]

Don't know what pump your talking about!
But when I replaced the shaft seals on the water pump of my old MD2B a few months back, Got the seals from local motor factors for 80 pence each, two of them they fit on the shaft back to back,
bought new bearings as well, cannot remember what they cost, but not a lot.
pretty straight foreward job, not that difficult to do.


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[30boat]

These pumps are usualy very easy to repair even if a new shaft has to be made in case the old one is worn.One thing to remember however is that you should keep the spring from the water side seal wich is stainless and subsitute it for the one on the replacement seal.Unless you buy the seals from Yanmar of course.
If you fit an ordinary seal it won't last more than a week.

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[paulrossall]

Had a similar problem 3 years ago when I was using a friends Evolution 26 which had a BMW badged 1cylinder diesel engine. Took the pump to French Marine motors at Tichmarsh marina. I had never taken a pump off before and did not know anything about them. French marine motors said they could not help as they did not have replacement seals for that pump and anyway they did not think it would repair and a new one would be over £100, probably nearer £200.
Took the pump to Halls at Walton-on-the Naze at about 5o'clock. They apologised that the could not repair it that day as they would have to go out to get the seals but would have it ready for 10 o'clock tommorow morning and it would cost about £25. Turned up at 10 next morning and the chap looked a bit unhappy so we thought the worst, however he said he was very sorry but job had not been straightforward and they had to send someone to Colchester for some part and thus the cost was £35. Pump was ready and repaired and has worked well since.
We were well pleased but it shows the different atitudes of two companies not 2 miles apart. So moral of story is watch out you don't get ripped off.
Must add that the actual Tichmarsh marina people are very helpfull and it is a good place to go, but I would not recomend French Marine motors given my experience.

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[vyv_cox]

You have had plenty of advice from others and you sem to have found out that the seal is a simple lip seal. Easy to replace. The only point I will add is that the shaft can wear where the lip contacts it, especially if the water it has been pumping is muddy or abrasive. Check that the shaft is OK or fitting a new seal will only be a temporary solution.

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[Avocet]

If you can get the seals and bearings out undamaged enough to read the part numbers, go to your nearest Bearing Services depot (BSL on the 'net). They'll be able to read the part numbers and get you an equivalent. Replaced the bearings and seals on my BMW water pump for about £10 I think. As someone else said, it is VITAL that you buy lip seals that have stainless or bronze springs. The ordinary carbon steel springs won't live long at all!

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