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Amc 304 Water Pump Rebuild??

Discussion in 'Intermediate CJ-5/6/7/8' started by Gordon Bachmura, Feb 22, 2021.

  1. Feb 22, 2021
    Gordon Bachmura

    Gordon Bachmura Member

    Las Vegas, NV
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    Feb 13, 2021
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    Has anyone rebuilt their water pump on their AMC 304? I'm working on a 72 Renegade with less 13,000 miles. But it has been sitting many years. Water pump is alright right now. But It has made in America cast in it. and if it starts leaking I'd like to just repair it. I've been doing a bit of internet searching but have yet to find a rebuild kit.
     
  2. Feb 23, 2021
    timgr

    timgr Eppur si muove. 2021 Sponsor 2020 Sponsor

    Medford Mass USA
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    I don't think it's practical to repair/rebuild one of these water pumps in your garage. And I doubt you could find the parts.

    The '68-72 water pump is different, and all retailers are selling the wrong pump for this application.
    68-72 V8 CORRECT NEW WATER PUMP (PHOTO!)

    If I planned to own this Jeep for more than a few years, I would buy a spare and put it away. Parts sources like this come and go.
     
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  3. Feb 23, 2021
    jeepdaddy2000

    jeepdaddy2000 Member

    Eagle Point oregon
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    I agree with timgr. If however, you are set on saving the made in USA pump, you could purchase a cheap pump at your FLAPS and disassemble it. That would allow you to get the bearing and seal numbers. If they are available over the counter, you could collect them and be ready when the old pump goes bad to attempt a rebuild.
     
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  4. Feb 23, 2021
    timgr

    timgr Eppur si muove. 2021 Sponsor 2020 Sponsor

    Medford Mass USA
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    This would be fine if the cheap pump were right for 1972. But it won't be.

    Somehow it is acceptable to sell a 1973 or newer style pump for a 1972. All the online parts listings for a 1972 AMC V8 show the later pump, and it's wrong. If you look at the pictures, the front bearing on the newer style pump is larger, and the casting changes to accommodate the larger bearing. The deck height of the newer pump is also different and your belts won't line up.

    I understand that GMB made the correct pump with an aluminum housing up until several years ago. They discontinued this model, presumably because the demand was too small to make them profitably. For a while there was no direct fit pump on the market, until these AMC specialist retailers started offering the iron housing pump I linked above, ca 2019.

    They say you can change to the later style pump if you can source a fan pulley for a '73 or newer. Supposedly your accessories will line up if you go to the newer pulley with the '73-up pump.

    The AMC car guys have been aware of this issue for a long time, since many of their cars are affected. For Jeep, only the '71-72 V8 Wagoneers and J-trucks, and the '72 304 CJ and Commando are affected. Most Jeeps with AMC V8s are newer.
     
    Last edited: Feb 23, 2021
  5. Feb 23, 2021
    jpflat2a

    jpflat2a what's that noise?

    Riverside CA
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    If I remember correctly, Jeep was furnishing pipe spacers to be used, if needed, with their new water pumps.
    We had a whole drawer full of those spacers for brackets and such.
     
  6. Feb 23, 2021
    timgr

    timgr Eppur si muove. 2021 Sponsor 2020 Sponsor

    Medford Mass USA
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    From the listings, the '68-72 pump has a 4.5" deck, while the newer one is 4.8". You'd have to put a 0.3" spacer under each of the accessory brackets or pulleys and the crank pulley.

    If I were in this position, I think I'd look for a '73-up fan pulley before the water pump failed.
     
  7. Feb 23, 2021
    Gordon Bachmura

    Gordon Bachmura Member

    Las Vegas, NV
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    I appreciate what you are saying. I do own and operate my own auto repair business. I have torches, welders, 20 ton press. pullers, etc. I was curious if anyone had any inside info on parts. But it a perfect world I'd love to keep the original housing because our jeep is mostly untouched.
     
  8. Feb 23, 2021
    Gordon Bachmura

    Gordon Bachmura Member

    Las Vegas, NV
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    I'll order one of those replacements for good measure.
     
  9. Feb 23, 2021
    timgr

    timgr Eppur si muove. 2021 Sponsor 2020 Sponsor

    Medford Mass USA
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    Yeah, with the right facilities and the parts you could rebuild it. There are businesses that do nothing but rebuild these scarce or obsolete pumps for classic cars. I suspect that parts and techniques for this are their trade secrets; not an impossible process to replicate, but hard to do in a one-off.
     
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  10. Feb 23, 2021
    Gordon Bachmura

    Gordon Bachmura Member

    Las Vegas, NV
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    Sounds good. Worst case I'll use the replacement then send out the original. You've seen the pics the the Jeep we have. I'd like to keep it original as possible. BUt after sitting so many years I expect we will chase a few leaks for a bit. I want to be prepared.
     
  11. Feb 23, 2021
    zila

    zila I throw poop

    Rock Springs,...
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    My water pump took a dump last summer. I replaced it with a high flow version. I wouldn't bother trying to rebuild one
     
  12. Feb 24, 2021
    jeepdaddy2000

    jeepdaddy2000 Member

    Eagle Point oregon
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    Ahhhhh.
    I assumed the bearings and seals were the same, just a variance in casing design.

    Well, we all know what "assume" means........:rolleyes:
     
  13. Feb 28, 2021 at 10:03 AM
    Keys5a

    Keys5a Sponsor

    Florida Keys
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    I've had limited luck at rebuilding water pumps. I've cracked a few cast iron impellers trying to press them off the old shaft. I've gotten a couple off intact, but broken more trying. Old-time rebuilders have their trade secrets!
    I'd send my '72 unique pump out for a rebuild to one of the specialist obsolete guys.
    -Donny
     
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