Sherwood water pump rebuild

[BillBerner]

I noticed a pretty fair amount of water leaking out the weep hole of the Sherwood water pump this weekend. The dried salt stalagmites were particularly worrisome.
Figured it was time for a rebuild, at least of the seals on the water side.
I've got the pump off and apart and am a little concerned about the amount of play that the shaft has with the seal and seat removed. Wondering now if the bearings are also shot, and if I should be 1 - rebuilding the whole thing, 2 - replacing it, or 3 - just put the new seals back in on the water side and forget about it.
Like a dope I havent checked the oil to see if it's milky.
Opinions?

Thanks

Bill Berner
C350 #66 Spartina
Stamford, CT

[BillBerner]

Replying to myself with an update for any who might be interested
I went ahead and put in the new seals and rebuilt and installed the pump.
It's running fine without a trace of leakage at the weep holes.
It was a very easy straightforward job. Don't even have a skinned knuckle!
Hope this may be helpful to others

Bill Berner
2003 c350 #66
Spartina
Stamford ct

[pdenoncourt]

Bill, I have been toying with the idea of rebuilding my old pump, but do not have information on what is required. Is there a rebuild kit available, or did you have to order all the parts individually? If a rebuild kit is available, did you find it to be adequate? Any info you can supply will be appreciated.

Thanks,
Peter Denoncourt
2003 C-350 #72
Kite, Jacksonville FL

[R.B.]

Just as additional info, in case you don't want to rebuild, you do not need to continue to use the Sherwood pumps. The Oberdorfer is a good replacement, since you can replace the impeller from the front without taking the pump off. There is some mild modification to be done to the pump in order to mount it to the engine, but common tools are all that is needed. Plus the pump is less expensive than the Sherwood.

Here is a link to the instructions:
http://www.c34.org/wiki/index.php?title ... Oberdorfer

[BillBerner]

Peter -

If you are seeing any leakage from the weep holes, I really encourage you to do the job. It's not a big deal

Again, I only rebuilt the water side of the pump. I had no signs of water leaking into the engine, or oil into raw water.

Getting an offset wrench for the water pump housing bolts will make removing them easy.

Take a look at this thread. It ends with a really good set of step by step instructions with photos. http://c34.org/bbs/index.php?topic=7489.0

If you use MarineDieselDirect.com (Toad Marine)
http://www.marinedieseldirect.com/catal ... P&size=600
you'll want -

302879 Sea Pump Gasket 1 2.95
302876 WASHER,FLAT PUMP 1 2.95
302885 Seal Assembly (Seat & Seal) 1 33.95
18145 RING,RETAINING 1 4.95 (no idea why this costs this much!)
18146 RING,RETAINING 1 2.95
302678 Sea Water Pump Mount Gasket 1 1.95

I didn't do the large retaining ring 18146, and wish i had. It was totally rusted, assumedly because of the leak and the fact that the old seat had not been permatexed. Prev Owner had been in there and installed a rubber grommet behind the seat that I ditched.

Oddly, the old small copper retaining ring was absolutely fine. Replaced it just because I was in there anyway.

I used a 1 1/2" Nylon Threaded end cap to tap in the new seat assembly.

Hardest part of the job was prying up the edges of the old seat to get it out. I wound up using a beat up old chisel. It worked well because the edge was thin enough to get a hold of the edges of the seat and it was rigid enough to bend up the seat edge.

While I had the pump off, I gave the outside a good metal brushing and doused naval jelly to get off all of the old corrosion and rust, and then gave it multiple coats of engine spray paint. The pump had obviously been leaking quite a while as there was a good deal of rust and corrosion that had started taking a toll on the pump body.

Before you remove the pump from the engine, take a picture of its orientation with respect to hoses, so you don't have to fuss around when you go to reinstall. I opted to remove the hoses from the pump cover, rather than just pushing the whole thing aside. Some people (not me) elect to stick a spare alternator belt on while the hoses are off, and tape it out of the way to make a broken belt easier to replace in the future.

As for the Oberdorfer replacement option. I didn't want to do all of the cutting req'd to make it fit, and didn't think a full replacement was necessary. & the offset wrench takes all of the pain and heartache out of impeller changes.

Good luck

Bill Berner
C350 #66
Spartina
Stamford, CT

[pdenoncourt]

Thanks, Bill. This is very helpful info. I considered the Oberdorfer option, but the pump body does not appear to have weep holes like the Sherwood and I thought that if/when the shaft develops a leak, it will end up in the engine. The weep holes are there to avoid that possibility in Sherwood design, and it obviously works.

I'm on my third pump now, having replaced the first 2 - $$! If I spend $150-$200 for these repair parts, that's about 1/2 the price of a new pump, so it seems well worth the effort.

Thanks again,

Peter Denoncourt
Kite, C-350 #72

[jrohrbaugh]

During a routine maintenance check I discovered, again, that my Sherwood G908 was leaking.
Put in new impeller and new gasket but leaked more!

So stuck at marina for an additional two days while I get a replacement from Depco.

New pump is now $530. vs. $395. In February of 2015.

How long should these last? I got about 250 hours out of previous pump and 320 hours this time.

Thanks for any info you guys can share.

Jamie
S/V Soixante
#444

[russp]

This might make you feel better Jamie, I put a new Sherwood G908 pump in 3 years ago, but for various reasons have only done about 100 hours since and it has started leaking.

Haven't taken it apart yet so see what damage, but your 250 and 320 hours looks good compared to my 100. I am suspecting that corrosion occurs regardless of use, and maybe these last a lot longer with more frequent use.

No one has mentioned that Catalina Direct now sell a complete drop in Oberdorfer, no body modifications required, Oberdorfer are doing them for the M35B.

Anyone have any experience with one?

Regards

[jrohrbaugh]

The new oberdorfer fit right in but the elbow needed to be replaced.
Impeller is slightly smaller so temp is about 5 degrees more. Looks and runs great after 50 hrs of use
I got mine from Depco.
See picture attached.
Elected to not keep sherwood as back up so still for sale.

[MarkElliott]

Found mine leaking while winterizing this year. After reading all the posts and looking at my schedule and the outside temp, I elected to call Depco pump and send it out to them in Fla. Short while later got a call from them with an assessment and gave a go ahead for a rebuild. Total cost for me $220 and shipping down to Fla from CT. Turn around time about 15 days door to door. They did the total job, even bead blasting the outside and repainting. I would still be staring at it on the floor of the cabin. Not that I don't think I could do it, but was well worth the money at this point. I'll reinstall it when back to the boat and then tackle the heat exchanger!.

[Flagmanmike]

I've not seen it yet, but I'm wondering if a weep hole could be drilled into the Oberdorfer pump. It would be a good tell tail if the the seal was leaking.

Mike Cronin
FlagShip #314

[MarkElliott]

Re-installed the pump today, the quickest boat chore ever completed. Sprayed a shot of silicone on the outlets prior to pushing the hoses on and they slid on very easy. A word of caution, when I took the pump off did notice a trickle of water coming from the hose I removed. Was able to elevate the hose and tie off to the engine and it didn't drip ( Im in the water year round). Seems the dripless shaft seal has a tube that goes to a T in the line from the raw water pump. This was back feeding and trickling out the disconnected line to the pump. Now how to get the antifreeze back into the engine. Seems to be air bound. Got a gallon in, but drained 2 gallons when I started the job. Temp goes up but fluid level under cap and in overflow container remains same. shut down at 190 degrees, let cool and did it again, no change. though it would suck in the fluid when it cooled. Ill let it sit a few days and see if it trickles down. Any tricks to this? Manual dosent indicate and special procedure.

[BillBerner]

There is a petcock by the thermostat at the top front of the engine. I believe you should be able to bleed out any air in the system from there.

[leigh weiss]

Mark, Second petcock by the hot water heater coolant lines. In the rear by the heater. Bleed this as you refill the manifold expansion tank.

[BillBerner]

is the one on the bottom of the heat exchanger raw water or coolant?

[TBOT422]

is the one on the bottom of the heat exchanger raw water or coolant?

raw water. Used to drain raw water out of the heat exchanger when replacing the zinc.

I've found that bleeding the air out of the coolant from the petcock at the thermostat to be sufficient. I found a small plastic hose splice at the local hardware store and attached it to a clear hose so that I could hold one end of the hose splice against the thermostat petcock while the engine was running. Coolant full of air bubbles flows into a container without making a big mess. Then poor the coolant back into the overflow container on the port engine compartment wall. Do not open the radiator cap to refill the coolant as that lets air back into the system. Of course you need to be very careful to keep your hands, loose clothing, and the drain hose away from the moving parts of the engine while it is running.

The petcock on the heater was a mess to work with. Hard to get to, no way to see it, etc. I wound up with a mess of coolant in the bottom of the boat that I had to clean up. Since then I only use the petcock at the thermostat.

Good Luck