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Water Pump shaft seal leaking 5.7, 350 Mag 300HP MPI - 2003

A

abl1111

Regular Contributor
Aaarrggh ! Water dripping from the pulley shaft seal !!!

I just removed this pump 5-6 engine hours ago, which is in a b*tchy location, to inspect / replace the impeller ( bloody knuckles, contorted position to reach it , a lot of cursing ! ) The seal had never leaked and looked fine when dis-assembled..

This is one of those, air purge water pumps - so it's $$$$ to replace.


My questions:

- Can the shaft / seal be rebuilt on this pump if the housing is fine ? Is it advisable ? The pump otherwise is in perfect condition i.e. impeller contact areas are not gouged...

- My serpentine belt felt like it had the right tension when I re-assembeled it the first time - could this have been too tight and blown the seal ? Again, I was very content with the tension - 1/2" flex

- The replacement water pump is pricey and I know some people use a regular water pump when this one goes - any issues with this ?

Thanks,

Bloody-knuckles II
 
abl1111 said:
- The replacement water pump is pricey and I know some people use a regular water pump when this one goes - any issues with this ?

Thanks,

Bloody-knuckles II
Click to expand...

There is no "regular water pump" replacement for a raw water pump. These are very specific to a particular motor/ cooling system type.

However... for the block circulating pump, if the engine is "freshwater cooled", i.e. a heat exchanger w/antifreeze setup, a "regular water pump" replacement is possible.
 
SAND - The raw water pump for my engine has a water-purging via pressurized air capability - the whole raw water side does. Many people do not replace the pump with this style due to cost - they install a pump that bolts on perfectly but does not have the purge capability. It's cheaper by a few hundred $.

BILGE RAT - I see some rusty water dripping ever so slowly from the seals when the boat is not in use. Indicative of a bearing issue ? I will pull out within the next day or so and check it out.

If bearings bad - is that a replaceable item as well ? Any way to bench test all this once reassembled. The PITA is removing and installing this due to it's location; deep down in bilge, and tight to motor beds. Would hate to reinstall without testing.
 
Raw water pump is out. Pulled it apart and want to inspect the shaft and seals.

Where do I attach the puller to take the pulley shaft off ? A special puller needed ? Does the pulley come off from the shaft and then the shaft just slides-out from the impeller side ? Or, do I need a hydraulic press ?

From schematic - looks like shaft and bearing are sold as one. If these are in working condition, I plan to replace the seals. Is there anything that needs to be hydraulically pressed in place ?

Lastly, is it better to just replace the pump and be done with rebuilding it ?
 
You will have to pull the sheave off the shaft to replace the outer lip seal (of course). Any 3 jaw puller will do the job. The inner oil seal can be removed by driving 2 screws into the seal and pulling them with a 2 jaw puller. Once you have the seals out, get a bright light and your wifes' best spectacles. First, look to see if there is any sign that the bearing races have spun in the pump body (not likely, unless the bearings have seized). If the bearings are intact in the pump body, clean them out with mineral spirits, and dry with compressed air. Visually inspect the bearings for any sign of corrosion or pitting. Re-oil the bearings with any engine oil, and spin the shaft, checking for any "feel" of grinding, binding, side-play - you know what i mean. If the bearings are clean and move freely, replace the 2 seals. Remember to use Loctite 609 adhesive on the outer (lip) seal. If your bearings are iffy you will have to replace the shaft and bearing assembly.
 
OK thank you - great directions ( that's all I needed ). I tried to pull the pulley with a two jaw puller - no go. I'll get a 3 jaw puller and get that off.

To clarify - I'll leave the shaft and bearings in - for now ( hoping for them too be OK ).

Re-installing the pulley - do I have to bring it to a shop for it to be pressed on ?
 
Got pulley/ sheave off. Tried (2) different (3) jaw pullers - couldn't get them to grab central point correctly. Needed a special 'pulley puller'. Done. Tried to drill (2) screws into the outer metal seal - no go. Instead, carefully used the edge of an old spackle knife with a hammer to tap - got some room, then a little more and carefully used a screwdriver to pry off.

Bearings both spin, but one has much more internal play than the other. And, the one with the play, seems to have moved from where it should seat on the shaft and was up against the other bearing. Stainless shaft looks fine although I do see marks where the old bearing was or was supposed to be. The pump housing where the bearings seat looks perfect too. If the bearings were perfect and (1) did not move, I would replace the seals and be done. But, at this point, I am going to replace this impeller side of the raw water pump. I'll reuse the old pulley, the other side of the water pump with the air purging set up and hopefully be on my way.

For academic reasons - why would the one bearing move ? Would the ID of the bearing wear or the SS shaft wear where it's supposed to sit ? Obviously, it's supposed to be pressed in place and not move.

Of Note: The reason this leaked - the bearing slid out of position and was not providing the shaft with even support on both ends - it was providing more of an off-sided support which allowed the shaft more wiggle room than it should, thus, leaning on seals, wearing them and allowing water in.
 
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