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Old 16-09-2012, 16:53   #1
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MD2020 Raw Water Pump Seal Replacement

A little lesson learned from last cruising season that I just remembered which I thought might be useful to others:

You can replace the front seal (water side) on an Volvo MD2020 water pump">Raw Water pump (actually a Johnson pump...so this probably applies to other engines too) without removing the raw water pump.

In the past, when seals on a raw water pump started weeping water (or oil) I always pulled the pump and rebuilt it. This is probably the best practice, but if pressed for time this tactic provides a quicker, easier fix.

Last season I noticed the raw water pump on my starboard engine weeping a bit of water (through the weep slot designed into the pump for this purpose), indicating it was time to replace the seal. I was a bit short on time (we were actually underway), thought about it for a minute, and realized I could probably replace this seal without removing the pump by removing the impeller plate and impeller. Sure nuf, opened it up, used a hooked pick to remove the old seal, and pressed in the new seal (I have a tool which I built from properly sized PVC to do this). Only took about 15 minutes.

Of course, if the other seal is leaking (on the oil side), its time to strip the pump and rebuild.
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Old 16-09-2012, 18:37   #2
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Re: MD2020 Raw Water Pump Seal Replacement

Good suggestion!

And for those who have not discovered this: The seals in most proprietary pumps (Johnson, Jabsco etc) can be purchased from any bearing and seal shop for somewhere around 2 bucks each... as opposed to 20+ bucks from your friendly Volvo, Yanmar, Nanni, etc bandit. Makes replacing them a lot pleasanter for me anyhow!

Cheers,

Jim
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Old 16-09-2012, 18:48   #3
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Re: MD2020 Raw Water Pump Seal Replacement

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Originally Posted by Jim Cate View Post
Good suggestion!

And for those who have not discovered this: The seals in most proprietary pumps (Johnson, Jabsco etc) can be purchased from any bearing and seal shop for somewhere around 2 bucks each... as opposed to 20+ bucks from your friendly Volvo, Yanmar, Nanni, etc bandit. Makes replacing them a lot pleasanter for me anyhow!

Cheers,

Jim
Absolutely! The prices Volvo charges for off-the-shelf parts are just criminal (200-300% above RETAIL in some cases!). Just get out the calipers and measure them -- there is nothing special about Volvo seals or bearings (except the outrageous prices they charge). Same is true for sail drive prop shaft seals.
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Old 16-09-2012, 19:12   #4
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Re: MD2020 Raw Water Pump Seal Replacement

Quote:
Originally Posted by belizesailor View Post
Absolutely! The prices Volvo charges for off-the-shelf parts are just criminal (200-300% above RETAIL in some cases!). Just get out the calipers and measure them -- there is nothing special about Volvo seals or bearings (except the outrageous prices they charge). Same is true for sail drive prop shaft seals.
Or, if you don't have calipers/micrometers or the confidence to use them, simply knock out the old seals and take them with you to the shop.

Oh... and be sure to have the shop folks take out the little coil springs that live inside the seals and replace them with o-rings. Makes the seals last a lot longer in a raw water pump!

Cheers,

Jim
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Old 16-09-2012, 20:13   #5
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Re: MD2020 Raw Water Pump Seal Replacement

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...

Oh... and be sure to have the shop folks take out the little coil springs that live inside the seals and replace them with o-rings. Makes the seals last a lot longer in a raw water pump!
...
Hey, another fine idea! Almost all I have replaced on the salt water side have died because that dumb-idea-in-the-first-place spring failed. Will have to try the o-ring substitute.
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