3126 Raw Water Pumps Issues and Questions

Discussion in 'Diesel Engines/Drives/Transmissions/Props' started by dtfeld, Feb 10, 2019.

  1. dtfeld

    dtfeld Water Contrails

    Jun 5, 2016
    Milton, GA
    410 Sundancer
    2001
    Axiom 12 MFD
    Cat 3126 V-Drives
    More raw water system fun today. I’m due for impeller replacement. I attempted to pull today using a short bolt into the impeller. Two issues, 1) They wouldn’t budge, and 2) not enough room to get them out due to oil senders etc in the way.

    I’ve read elsewhere that removing the entire pump is a better option. So I think I’ll buy 2 new or rebuilt and send the other two to out be rebuilt, and swap them out on schedule or as needed. Pulling the whole assemble sure seems easier

    Couple questions.

    Does the Sherwood 1732C I see online com with the gear attached? Most suppliers aren’t too specific.

    How hard is it to press the gear on/off?

    Any recommendations for a place to rebuild the pumps? Seems CAT might have some rebuilt. New is an option as well.
     
  2. carterchapman

    carterchapman Well-Known Member TECHNICAL Contributor SILVER Sponsor

    Mar 25, 2008
    Lake Chickamauga/Marietta, GA/Ft. Myers, FL
    2006 Sea Ray 58 DB
    MAN CRM V8-900s, Twin Disc Drives; Onan 21.5 Generator
    FrankW will chime in on pressing the gear on/off. Pumps do not come with the gear. I recall that I disconnected the fuel line to the fuel cooler, disconnected the electric oil pressure sender, and then rotated the fitting 90° outward, and that gave me plenty of room to pop it out with the bolt. When you disconnect the fuel line pull it up to the top of the engine, and very little fuel will come out (use a diaper). On the stbd engine, I removed the fiberglass exhaust hose for better access...
     
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  3. dtfeld

    dtfeld Water Contrails

    Jun 5, 2016
    Milton, GA
    410 Sundancer
    2001
    Axiom 12 MFD
    Cat 3126 V-Drives
    Mine are of unknown age and status. They also have a lot of rust in the weep holes and look to have been leaking at some point. I think it’s time to buy a replacement set.

    Was hoping they came with a gear, then I’d have a complete replacement set.
     
  4. Korkie

    Korkie Active Member SILVER Sponsor

    381
    Feb 2, 2016
    Leonardtown, MD Potomac River / Chesapeake Bay
    340 Sundancer 2006, Garmin 7612, xHD Radome
    Merc 496 Mags, Bravo III Drives
    You can certainly get the gears as well and put them on so you have complete units. That is what I did for my spare.
     
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  5. fwebster

    fwebster Well-Known Member TECHNICAL Contributor PLATINUM Sponsor

    Oct 6, 2006
    Middle Tennessee ; Panama City Beach, FL
    1996 450DA
    3116 Caterpillars
    The seawater pumps are driven off the accessory drive on the front of the engine. The gears are a Cat part, the pumps (from the shaft back) are from Sherwood.

    Pressing the gears off the shaft is easy and can be done with a large vice and 2 large screw drivers if you do not have access to a proper hydraulic press. The shafts/gears are tapered so pressing the gears on the new pumps is a matter of tightening the nut on the shaft.

    Rust inside the pump housing indicates a sea leak in the pump at some time in the past. Sherwood improved the pump design at some point in the past and if you don't know which pumps are on your engines and you see a leak, I would not spend the $ buying shaft, seals, bearings etc. from cart to rebuild old seawater pumps because you can spend most of the cost of new pumps on rebuilding old ones......and you still have old pumps.

    Depco pumps in South Fla is a great source with excellent technical help available, but you are going to shop all over the internet anyway so just sure you are shopping for the latest Sherwood design for the 3126 engine.
     
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  6. dtfeld

    dtfeld Water Contrails

    Jun 5, 2016
    Milton, GA
    410 Sundancer
    2001
    Axiom 12 MFD
    Cat 3126 V-Drives
    Price difference between 2 new and remans is about $100. I think new is better deal.

    Impeller cover indicated P1732C. Which is the newest version in that family according to sherwood website.

    The major rebuild kit includes new shaft, bearing, seals, everything except the housing (that shouldnt require any rework). The avanatage for me is having a set of pumps that can be quickly swapped out, and rebuilt at my leisure. I would think a rebuild would last at least a impeller changes.

    I've read Frank's thinking on new vs rebuild and I agree that the cost between new and rebuild kits makes the rebuild a little dubious from a cost/benefit standpoint. I may try a rebuild when its time, but I'm also in fairly deep and clean fresh water, so I dont expect to have the same wear issues you folks in skinny salt water do.

    Man these are a royal pain to get to!
     
    Last edited: Feb 11, 2019
  7. dtfeld

    dtfeld Water Contrails

    Jun 5, 2016
    Milton, GA
    410 Sundancer
    2001
    Axiom 12 MFD
    Cat 3126 V-Drives
    For anybody that has replaced these pumps is there a service manual with the procedure?

    Looking for details like do I need to grease the gear teeth, torque specs for the bolts and do you need any Blue (removable) loctite ?
     
  8. Rssll45

    Rssll45 Member GOLD Sponsor

    73
    Feb 16, 2009
    New Orleans
    1998 450DA
    Cat 3126
    Did this a couple of years ago. New pump $827. Rebuild $412 parts $250 labor=$662. Gear for spare pump $189. At that time the new pump was a P1732A. One heads-up; on the new pump the keyway in the shaft does not go all the way out to the end. In other words you cannot alien the impeller with the keyway and slide the key in. You have to place the key in the shaft, then alien the impeller and push it on. Not knowing this made for a very interesting project at the first impeller change.
     
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  9. fwebster

    fwebster Well-Known Member TECHNICAL Contributor PLATINUM Sponsor

    Oct 6, 2006
    Middle Tennessee ; Panama City Beach, FL
    1996 450DA
    3116 Caterpillars
    You shouldn't grease the teeth on the pump drive gear because it is in the accessory drive chamber is oiled by the engine's oiling system. The nut holding the gear on the tapered pump shaft hs a lock washer behind it so Locktite shouldn't be necessary.
     
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  10. dtfeld

    dtfeld Water Contrails

    Jun 5, 2016
    Milton, GA
    410 Sundancer
    2001
    Axiom 12 MFD
    Cat 3126 V-Drives
    Looks like this should be fairly strait forward, except for getting the damned thing out of the boat!
     
  11. dtfeld

    dtfeld Water Contrails

    Jun 5, 2016
    Milton, GA
    410 Sundancer
    2001
    Axiom 12 MFD
    Cat 3126 V-Drives
    Out with the old and in with the new! Gear easily removed with gear puller borrowed from Advanced Auto Parts. Just need to clean up/descale the elbows, and install new o-ring seals. Finally starting to put things back together instead of tearing things down.

    20190220_134639.jpg

    Torque spec for the gear is 47 +/-5 lb-ft or 63+/- N-m

    Torque Spec Water Pump.PNG
     
    Last edited: Feb 20, 2019
  12. JVM225

    JVM225 Well-Known Member GOLD Sponsor

    Apr 8, 2008
    Farmingdale, NY
    2002 410 Sundancer, Monaco Edition.
    3126 Cats.
    New pumps?
    Gotta love the tool loaner program at the big box auto parts stores.
    Unfortunately, most of their replacement parts are Chinese crap though.
     
    dtfeld likes this.
  13. dtfeld

    dtfeld Water Contrails

    Jun 5, 2016
    Milton, GA
    410 Sundancer
    2001
    Axiom 12 MFD
    Cat 3126 V-Drives
    The port one showed signs of leaking, so both of the pumps were on the list.

    Basically the whole cooling system is getting reworked...descale all the coolers, new hoses, new pumps.

    Hopefully I’m done with the major systems for a while.
     
  14. HUMPH

    HUMPH Well-Known Member

    Nov 4, 2009
    SF BAY AREA
    2003 410DA,
    2004 C14 Caribe
    CAT 3126TA's 350HP/
    50HP Honda
    I replaced both of mine a few years ago. Port side is 1.5 hours start to finish but the starboard side is double that at least. I used a gear puller to remove the gear and used a mallet and the nut to press them onto the new unit. Remove the exhaust pipe on the starboard side to gain access and save a lot of frustration. I remove it even to change impellers.
     
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  15. dtfeld

    dtfeld Water Contrails

    Jun 5, 2016
    Milton, GA
    410 Sundancer
    2001
    Axiom 12 MFD
    Cat 3126 V-Drives
    I attempted to remove the black rubber exhaust hoses, but they might as well be welded in. Ended up removing the hard pipes and that made enough room to get the pump off the starboard engine.

    Is there a trick to getting the 6” hoses off with out cutting them off?
     
  16. HUMPH

    HUMPH Well-Known Member

    Nov 4, 2009
    SF BAY AREA
    2003 410DA,
    2004 C14 Caribe
    CAT 3126TA's 350HP/
    50HP Honda
    I take mine off from the stainless elbows to the first hose connection. Trying to take just the hoses of I wish you luck!
     
  17. dtfeld

    dtfeld Water Contrails

    Jun 5, 2016
    Milton, GA
    410 Sundancer
    2001
    Axiom 12 MFD
    Cat 3126 V-Drives
    I couldn’t get them off the stainless elbow either. I have a hose removal tool, but man that hose it tough stuff. Maybe heat them up?
     
    Last edited: Feb 21, 2019
  18. fwebster

    fwebster Well-Known Member TECHNICAL Contributor PLATINUM Sponsor

    Oct 6, 2006
    Middle Tennessee ; Panama City Beach, FL
    1996 450DA
    3116 Caterpillars
    If the hoses have been off before, the usual method is to use Merc Perfect Seal to prevent leaks. Perfect Seal (Gorilla Snot) is alcohol based so some denatured alcohol usually helps loosen the bond between the stainless or fiberglass tubes and the hoses.
     
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  19. dtfeld

    dtfeld Water Contrails

    Jun 5, 2016
    Milton, GA
    410 Sundancer
    2001
    Axiom 12 MFD
    Cat 3126 V-Drives
    Gorilla Snot???!!! LoL. I learn something new here every day.

    So maybe inject some denatured alcohol in the joint as I work them? If I get them off, do I need to replace the hose or reseal with gorilla snot?

    I think John (JVM225) said he has silicon hoses and they could be “rolled back”. Is this an option for replacement? I’d like to get to the point these things are serviceable. Lots of things needing service hiding behind the exhaust in this thing.
     
    Last edited: Feb 22, 2019
  20. ttmott

    ttmott PhD in OCD GOLD Sponsor

    Apr 3, 2012
    Space Coast Florida
    2006 52 Sedan Bridge
    Cummins QSM11
    Stainless steel cake knife with smooth edges. Slide it in and around between the hose and tube then wiggle the assembly until they start to come apart. I bet I removed the starboard exhaust twenty times on my 400DA to service the generator, impeller, and other things in that area. Put them back together with silicone lubricant spray and don't forget to reattach those bonding wires.....
     
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