Water Leak?

[SEMIJim]

I just replaced the impeller and installed the MMI thumb-screw back-plate. Ran the engine. Somewhere there's a water leak. It's a pretty substantial "trickle." (Much higher rate than by packing gland, for example.) I'm 99.999% certain it's not the new back-plate. It seems to be coming from further back, but I cannot see from where. I notice there's a kind of rectangular hole or slot on the top of the pump, between the main body and the mounting flange? Can't see the water coming out of there, but that seems to be about where it's coming from.

When I pulled the old impeller, it came out shaft and all. And, in fact, I had to "punch" the shaft out of the old impeller and I ended-up using wet/dry sandpaper to sand the part of the shaft where the impeller slides-on to get the new one to go on w/o forcing it.

There was a bit of scoring where the bearing in back is, I assume. I lubed that part of the shaft with a bit of marine lithium grease before putting things back together.

So from where could the water be coming? Do I need a new pump?

Thanks,
Jim

[msmith10]

It sounds like you have a leaky seal. Look in the Moyer online catalog:Product No. - CSOB_04_65
These are easy to replace. If the shaft is significantly scored you may want to replace it also.
If you rebuild the pump, make sure you install the seals correctly. They should go back in with the lettering on the seals facing each other.

[SEMIJim]

It sounds like you have a leaky seal.

Yeah, that's what I was suspecting. What are the short-term implications of this? Will I end-up with water in the oil system?

Thanks for the info, msmith.

Jim

[SEMIJim]

Water Pump Rebuild How-To?

I seem to recall seeing a water pump rebuild how-to somewhere? What that somewhere here on the site, or in my MMI A4 maintenance and rebuilding manual?

Thanks,
Jim

[sastanley]

Jim,
One of the seals keeps the oil out of the water, and the other seal keeps the water out of the oil, and there is a weep hole (the rectangular hole) in the middle. I think only careful observation can determine which may be happening in your case (water in the oil sump would be the worst).

The pump comes off with two bolts...9/16" (14mm) if I recall. The seals can be yanked/pried/plucked out with a screwdriver and pressed back in with a hammer and socket that fits just inside the diameter of the shaft housing.

Don't forget to check the grease cup and make sure it works correctly during this process as well. Have you checked that already? Maybe some grease in the cup might re-seal the shaft?

I am guessing that when you punched out the shaft, you may have damaged one of the seals..hopefully the outer one which is causing the water to leak past the shaft to the weep hole, and not the inner one which keeps the water out of the oil, and also the oil on the inside half of the shaft in the sump where it belongs (I think...)

[SEMIJim]

Jim,
One of the seals keeps the oil out of the water, and the other seal keeps the water out of the oil, and there is a weep hole (the rectangular hole) in the middle. I think only careful observation can determine which may be happening in your case (water in the oil sump would be the worst).

Yeah, water in the sump would be Bad News. Since the water's dripping down the outside, I'm going to hope that, until I can get her in her permanent slip, when I can then have the time to remove the pump and re-build it, water's not getting in there. Since the weep hole is there (that's what I figured that might be), there'll be no water pressure on the inside seal, right?

Don't forget to check the grease cup and make sure it works correctly during this process as well. Have you checked that already? Maybe some grease in the cup might re-seal the shaft?

There is grease in the cup (I took it off), and it appeared to be in good condition.

I am guessing that when you punched out the shaft, you may have damaged one of the seals...

I didn't punch the shaft out of the pump, the shaft just slid out when I went to pull the impeller out. (And I went to so much trouble, contorted into an exceedingly uncomfortable position, getting that !#$!!! snap ring off, too!) No, I had to punch the shaft out of the impeller once the whole thing was out. Like I said: The new impeller wouldn't go onto the shaft. I had to sand-paper the part the impeller goes on down, first.

Thanks for your comments.

Jim

[marthur]

Pump rebuild photos

Just in case it helps, here is a link to pictures my kids and I took of a water-pump rebuild.

http://home.earthlink.net/~imgerm/water_pump/pump_rebuildi.htm

Goood luck,

Mike

[rheaton]

FYI, Don's video on the A4 cooling system demonstrates a water pump rebuild.

[SEMIJim]

FYI, Don's video on the A4 cooling system demonstrates a water pump rebuild.

Ah! Why didn't I think of that? I have the reversing gear video, and that was tremendously helpful. Thanks for the reminder. I'll order that with the parts. Thanks!

Thanks also to marthur. I'll take a look.

Jim

[Kurt]

Do yourself a favor and rebuild the whole pump by ordering the rebuild kit from Moyer. It comes with detailed instructions, both seals and a new shaft. I rebuilt my pump 3 times in a particular few months I was having perplexing problems that I won't get into here. Suffice to say, the pump is not that hard to rebuild and I got to where I could replace the guts during a rebuild in about 30 minutes.

[jayhearts]

Water Pump / Accessory Drive Leak

Jim,

In a 4/13/05 reply Re: Water Pump Installation, Don say's "#3..use sealant on mounting bolts.. since the Mounting bolts are somewhat subject to letting engine oil seep out from the crankcase.." This surprised me, as I would have thought the mounting bolt was threaded into a "dead-end" hole. Kurt was helpful with a similar problem, but before re-building the water pump AGAIN, I tried the sealant fix first. I have photos, (which I am unable to upload) which clearly show the lower bolt carrying oil. contact me directly and I'll share them.
This may not be YOUR cure, but it beats replacing something and not getting an improvement.

[Administrator]

Your image was rejected by the forum software because of its size (2.1MB). I resized it (172 KB), and it loaded just fine.

Bill

[SEMIJim]

Jim,

In a 4/13/05 reply Re: Water Pump Installation, Don say's "#3..use sealant on mounting bolts.. since the Mounting bolts are somewhat subject to letting engine oil seep out from the crankcase.."

That's not my problem. My problem is a water drip/leak. But thanks for the heads up, anyway. I'll put a touch of Permatex on the threads up near the head of that bottom bolt before putting it back in.

Jim

[SEMIJim]

Still Drips!

I did the water pump rebuild today. Replaced both seals and the impeller drive shaft. Fired it up and watched it. Horray! No leaks. Watched it a bit longer and... I'm still getting a slow drip! It's a lot less than before the rebuild, about one drip every 10 seconds or so, regardless of engine speed. Other than replacing the pump, guess there's nothing more I can do. Perhaps once things settle-in, it'll stop. (Won't know. Not a place you can see, normally.) I'm going to call it "good" and sail the boat. Whatever water's getting past that outside seal I doubt will get past the weep hole, past the inside seal and into the engine--and that was my main concern.

Some recommendations: Buy the slip-ring pliers from Moyer (mine didn't fit), get the replacement grease cup (mine's still "ok," but not great), and get the extended bottom bolt! That bottom bolt is a PITA! (Especially when you're 6'4" tall, crammed into the starboard lazerette, and working left-handed .)

Getting the old seals out didn't turn out to be as easy as it was for Don in his video. The inside seal (of course) came out in pieces, leaving the outside of the seal firmly in place. Took a bunch of prying and wrenching and pulling and so-on, but finally it came out. I don't know if it'll help the next time, but I put anti-size on the inside of where those seals go, hoping it'll make removal next time easier.

[rigspelt]

Grease up whatever lies in the path of that water, until you have a chance to stop the leak. I spent hours cleaning up rust on a mounting bolt.