Impeller stuck in Sherwood raw water pump housing

Went to change the impeller on my Cummins 330 B which has a Sherwood raw water pump. (Yes, I know, Sherwood = $#%@X).

Usually the impeller comes right out with the use of two needle nose pliers. Not this time.

Got a 3/4" 16 thread bolt, per Sherwood instructions, and tightened that in as an "impeller removal tool". Impeller grudgingly came out 3/8" and refused to budge any more. Honking hard on the wrench now just causes the pump and impeller to (not easily) rotate.

Local marine diesel mechanic tells me that "she's frozen on the shaft" and my* day just got worse as now I must remove the pump which, because of the location of the engine mount, means I have to uncouple that mount and somehow lift the engine before the pump gear housing/mounting plate can be withdrawn past the engine mount.

Oh Joy!

Anyone have any wondrous words of wisdom, advice, easier solution, consolation?

David,
I am not familiar with your pump, but is it possible to spray penetrant on the shaft and drive it back in then pull it again? I know it sounds counter productive, but I've learned that when o am removing a pin from a very tight bore I can do this several times and often be able to get the pin out with little effort. Might work with your problem?

David,* I remember I saw an impeller puller tool online somewhere.** Maybe you can google it.** In your case it might be a worthwhile addition to your tool kit, considering have difficult the pump is to remove.

Good Luck,* JohnP

Forkliftt wrote:
David, I am not familiar with your pump, but is it possible to spray penetrant on the shaft and drive it back in then pull it again? I know it sounds counter productive, but I've learned that when o am removing a pin from a very tight bore I can do this several times and often be able to get the pin out with little effort. Might work with your problem?

That sounds like a good idea.* If it can be moved at all, a penetrating oils and moving it back and forth may well free it.

Click to expand...

*

Forkliftt wrote:
David, I am not familiar with your pump, but is it possible to spray penetrant on the shaft and drive it back in then pull it again? I know it sounds counter productive, but I've learned that when o am removing a pin from a very tight bore I can do this several times and often be able to get the pin out with little effort. Might work with your problem?

Click to expand...

*Yup. Thanks. I will try that. Saw it as a suggestion on BoatDiesel.com and well worth a try.

JohnP wrote:
David,* I remember I saw an impeller puller tool online somewhere.** Maybe you can google it.** In your case it might be a worthwhile addition to your tool kit, considering have difficult the pump is to remove.

Good Luck,* JohnP

Click to expand...

*Local mechanic swore, from his extensive experience, if it won't come off with the bolt bit, it won't come off with an impeller puller. Hamilton Marine, about 40 miles down the road from me, sells a puller for about $80. Do I drive 80 miles round trip at 20 mpg X $4/gal, plus $80 for the puller, plus 5% sales tax, or do I try Forklift's penetrant routine and, if no go, spend some flesh, blood and expletives and attempt to remove the pump?

As an added bit of info, the pump is weeping a bit near the "front seal" onto the engine mount (i.e. rust evident) and the BoatDiesel threads indicate this may mean I should consider a replacement unit of another, superior, manufacturer, at added cost. But I think that this info means that, in any case, I should get the Sherwood off in any case and take it to the experts for evaluation.

I suggest you replace the Sherwood with a Seaboard pump. As you know Sherwoods are #@!@# and Tony's pump is a vast improvement. Overnight shipping and likely cheaper than Sherwood.

Spraying with WD or your choice of lube then pushing it in, then using the bolt extracting method should work. Might have to do that a few times. It is also possible that the bolt is pushing the key and that is jamming the impeller on the shaft. I had ground the bolt shank to put a chamfer so the diemeter was less than the shaft diameter and would not touch the key.

You might try that.

If not then take the whole pump off and work on the bench.

You'll have to remove the engine mount to get the pump off. Easy job. I did it and it takes "maybe" an hour providing you cann get a small hydraulic jack under the front of the oil pan...use a block of wood on the pan, jack to support only.

*

If it is weeping around a seal now it won't get better. I would take if off and have it rebuilt...or look on ebay for a new one.

Doc is right - leaking pump means pump body replacement time. But, why buy a !@#$* Sherwood on e-bay (which would probably be a leaker too) when a perfectly designed replacement for the !@#$* is available from Seaboard - you would have it Tuesday. If not done so yet, read the boatdiesel archives on Sherwood pumps. While you are at it, double check your belts, idler pulley and damper. they are all*potential trouble *points on the Cummins.*

The raw water cooling system on your**330 *is the lifeblood of Cummins longevity. Oh by the way, did I say the weak point on your otherwise great engine is the !@#$* Sherwood pump?

A few years ago,*I reported about my 1000's of hours of excellent Sherwood experience*on boatdiesel.com, but there wasn't anyone there interested in hearing about it.

To be sure, the 330HP (and other higher horsepower versions) use a larger pump than the one used on my 210HP model.* And it is very true that as more horsepower is produced from this block, the importance of the cooling system design and condition are increased.

Certainly, if I had a need for additional cooling and/or reliability, I would consider one of Seaboard Marine's pumps.* Meanwhile, the Sherwood continues to perform well, with scheduled impeller changes every 750 hours, and a minor rebuild every 2250 hours or so.

Also, and if your installation permits, see if your port fwd motor mount can be replaced or customized so that the pump can be easily removed and/or impeller easily serviced.* This*works good for my single 210HP engine, I realize that twin installations can have*room-to-work challenges.

Leaking around the seal won't get better, but may take years to get much worse. My "new" Starboard engine came to me with a leaking seal on the water pump. the mechanic who sold it to me noticed the leak right on start-up and recommended a replacement pump, as a rebuild would cost almost the same. I let it go 7 or 8 years and it never got any better. It never got worse either, but I started to want a drier bilge, so replaced it. I now have a leaky spare. In that time I haven't had to replace the impellers either, so my leaky spare has a perfectly good impeller with 1400 hrs and or 8 yrs use on it. Inspection revealed no cracks or visible wear. The inside of the cover shows a little wear.
Unless you are removing the impeller due to failure, push it back on and close it up until you are motivated to make that pump a spare.

Update.

Using lots of PB Blaster and working the impeller in and out over several hours, the blasted impeller finally came out. Good thing as I couldn't figure out how I was going to lift the left front of the engine off of the engine mount to enable the pump to be removed. Couldn't find any location to put a jack, wedges or whatever in there to do it.

New impeller went in easily once I could get the Woodruff key lined up (another pain).

Have decided that we don't want to ever have to deal with replacing an impeller in this pump (stuck or otherwise) in an emergency situation out on the water, or having to lift the engine to remove or replace the pump, so we will be buying a Seaboard pump soon and sometime this summer have the local yard, with its knowledge and expertise, install it. Will cost us, but have decided peace of mind is worth it to us.

May also have the yard eliminate some of the adjacent obstructive plumbing that Tony talks about which is definitely a pain to work around when trying to replace the impeller.

http://sbmar.com/main/article/dealing_with_the_seawater_pump_on_a_cummins_6bta_5.9/

Thanks everybody for all the feedback.

I always put some anti-sieze compound on the shaft before putting the impellor on. Never had a sticky one yet. My pump is the M71 and is the same 210hp config as Jay N.

"Have decided that we don't want to ever have to deal with replacing an impeller in this pump (stuck or otherwise) in an emergency situation out on the water, or having to lift the engine to remove or replace the pump,"

Have you contemplated using an electric pump , with a backup?

It could be located where ever its really easy to service.

It's interference with the key

Hi... I know this is years late but just in case someone comes looking to solve the same problem. The reason your 3/4" bolt gets jammed up is that it comes in contact with the key which can slide out to meet the bolt threads. Total B*TCH to turn it either way once you get there. Try pushing the key back in deeper with your finger... works on mine. The problem with the theory about using a 3/4" bolt as the totality of the impeller pusher is this key interference. To cure that, I made my own... a 3/4" bolt was cut off just enough so it gets a purchase on the threads in the impeller. I drilled and tapped a hole into that for 3/8"-coarse (I don't want to be turning it forever) female thread, and turned a bit of metal down to accept a 3/8" male thread. Added a few doodads like bevels and things to stop my wrench from slipping off and I was off to the races. Time to remove impeller with this... 2 min?

Having a lathe is a good thing. Here's a pic of the result if you're interested:

Hey... make sure you don't forget the little "cover saver" plastic hooha when you're reassembling. It's in that kit for a reason.

Gilhooley

Oh my, make one for me. PLEASE!!

No lathe needed...

hmason said:

Oh my, make one for me. PLEASE!!

Click to expand...

If I ever get within sight of a place called "caught up", I'll make up a few spares

Seriously... I bet this is totally doable without a lathe. Thinking... instead of making the pusher part, get some 3/8 threaded rod or whatever they sell that's near that (hardware store)... So......

1. cut the 3/4 bolt to length (get one where the threads go all the way up to the head... some don't)... vice and hacksaw

2. drill it to the minor diameter for a 3/8 thread (should say on the tap but looks like it's around 0.320" - get it from here: Tap Chart UNC/UNF Threads - provides tap sizes, drill sizes, pitch, (threads per inch) basic major diameter, basic effective diameter, basic minor diameter of external threads, and basic minor diameter of internal threads for UNC/UNF threads). - vice, drill, punch (drill press is better)

3. Run the tap into the hole you just cut... tap, tapping fluid and vice

4. Cut off a piece of the threaded rod (slip a nut on it before you cut it so you can clean up the thread after you cut). I'd say: length of your impeller plus a couple inches. hacksaw and vice.

5. put a nut, and a second nut on the very end... tighten them against each other... these form the head. Loctite maybe?

6. Thread that into the 3/4 piece from step 1.

Bask in the warm glow of having murdered this problem yourself. Shoot me a message if you get stuck. Good luck... you don't need it

Hint - For every thread diameter, you usually get a couple of different pitches (coarse & fine). Don't use the fine thread... less turning... you have more than enough mechanical advantage with coarse. You'd have to go with whatever you can find for threaded rod but I think that'd be coarse.

Gilhooley

Thanks for the instructions. We live aboard and I have no way to do that. If you make me one, I'll buy it.