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Raw water pump bearing replacement

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Old 06-20-2022 | 11:29 PM
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Default Raw water pump bearing replacement

One of my raw water pumps wasn't sounding so good after it's winter nap. (Merc# 46-71497). Bearings are bad.

I've removed the pressed on piece that the pulley bolts to but can't figure out which direction the shaft needs to go to get the bearings out. Tried to use my large vise as a press but no luck either direction. Got the water pump side seal out but don't see any snap rings/etc holding it together..

Anyone know which direction the shaft needs to go? Towards the water pump or towards the pulley??
Any other hints??

Thx!!
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Old 06-21-2022 | 04:01 AM
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I rebuilt one of my raw water pumps recently, it's the newer style with serpentine pulley, but it may be similar. Behind the pulley was a circular cover (pry out with screwdriver or similar), over a snap ring, which had to be removed so that the bearings and shaft could be pressed out from the impeller side forward towards the pulley side.
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Old 06-21-2022 | 11:14 AM
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Thx Doc. I've attached a couple of pics. Does it look like yours? I called the bearing place locally and gave them the National 43361 XAO number. They said it's a seal (and they don't have one).


Before removing pulley hub.

After removing pulley hub.

Last edited by zz28zz; 06-21-2022 at 12:33 PM. Reason: Had wrong part name.
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Old 06-21-2022 | 11:23 AM
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Also, how big of a press was needed/used? I found a 30-ton hyd sorta close-by. Assuming that would be plenty.
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Old 06-21-2022 | 11:26 AM
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Looks similar though not identical.

Basically you press out the shaft and it will have the bearings on it. Then new bearings placed on the shaft and it's pressed back into the housing after the new inner seals are installed (between bearings and impeller).
I agree that silver cover / plate is a seal, probably just need to pry it out with a thin tool.

30 ton should be way more than adequate.
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Old 06-21-2022 | 11:28 AM
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Here's an exploded view of the bearings and seals.



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Old 06-21-2022 | 11:42 AM
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Remove seal first last pic post 3 and item 14 in the above pic
Once seal is removed, you can get to the snap ring

Won't need a large press, but probably need bearing splinters or similar to remove and replace bearings. Need to press against the inside race, not outside
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Old 06-21-2022 | 12:29 PM
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Thx guys!

Found the pump on BAM: Appears the parts are all still available (that I need). Abt $243 to rebuild both both pumps + cost of press. Still better than ~$1100 for 2 new pumps. Already have new impellers.
https://www.mercruiserparts.com/bam/.../31920/959/300

Ok on the bearing splitter.

I also found a 12-ton press locally. Looks like a Harbor Freight item. No extra goodies..
The 30-ton press is shop made and comes with a bunch of adapters/etc.

I figured the 30-ton was overkill, but better too big than too small and I always wanted a good press.

Used a harmonic balancer puller to remove the pulley hub from the shaft with a 18" 1/2" breaker bar on it. Thought the puller was going to break! I'd prefer not to use that method again.



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Old 06-21-2022 | 12:41 PM
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There is a seller on ebay who has compiled a kit for rebuilding. I think I paid $60 for it.
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Old 06-21-2022 | 12:43 PM
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https://www.ebay.com/itm/112486665474
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