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Water pump leak - Lower bolt - PROBLEM LOCATED

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  • Cool/Heat: Water pump leak - Lower bolt - PROBLEM LOCATED

    I've been working on this issue for a while - previous thread can be viewed here - 51 Champion


    Installed a new manufactured replacement pump with a paper gasket. I also added a thin layer of RTV. System was filled with water/coolant and started the engine for the first time in months. Thought all was well until I noticed water leaking from the lower side of the pump. I believe the water is leaking from behind the bolt (see video link)

    Is reinstalling the water pump my only option? I did try and re-tighten the bolt. The bolts are from the original failed pump. I didn't notice any leaks around other areas of the pump. Thanks in advance for suggestions.

    Last edited by Photoguy; 03-29-2019, 03:05 PM.

  • #2
    I took the time to look at your video. That is a substantial leak. But before you launch into a major reinstall...a question and a suggestion. If that is the only bolt that is leaking, I suggest you remove and replace only that bolt. Do not tweak or try to tighten any of the bolts if they are correctly torqued to their recommended torque specification. (A lesson I have learned the hard way.) In the world of threaded fasteners (nuts, bolts, screws) there is a thing called "percent of thread," related to the contact fit between the threaded shaft and the mating part. It is possible that the bolt is just not a good threaded fit, or it has been compromised from rust or corrosion over time. In addition, you could coat the threads with a light amount of adhesive like RTV, or a mild loctite. Drain the coolant and give the adhesive time to set before refilling and getting it wet I would hesitate to use the strongest grade of loctite because you might want to remove it later and some of the loctite formulas require heat to break the bond.

    Give this a try and let us know the results.
    John Clary
    Greer, SC

    SDC member since 1975


    • #3
      Do the sixes use copper washers like the V8s?
      78 Avanti RQB 2792
      64 Avanti R1 R5408
      63 Avanti R1 R4551
      63 Avanti R1 R2281
      62 GT Hawk V15949
      56 GH 6032504
      56 GH 6032588
      55 Speedster 7160047
      55 Speedster 7165279


      • #4
        I use permatex on the threads of any bolt that goes into a water jacket. Haven't had one leak in over 40 years.


        • #5
          Be very careful to check the DEPTH of the Hole in the Block and the Water Pump thickness the Bolt must pass through.

          It is very possible that you got the wrong length bolt in that hole, OR it is just TOO long and bottoms out before actually snugging up on the Pump.
          Debris in the Hole?

          So I guess from your other Post that we never heard how it was resolved, that you exchanged the Pump for the correct one, and hopefully it is a New one, not a rebuilt one?
          Last edited by StudeRich; 03-25-2019, 09:58 PM.
          Second Generation Stude Driver,
          Proud '54 Starliner Owner


          • #6
            Thank you for the input. I didn't want to have to pull the pump again since everything else was staying tight and dry. I thought about applying a sealant of some sort but wasn't sure if that would be appropriate for this issue. I will try that and check the bolt depth as well. Incidentally, I could not find the recommended torque specs in the manual. I may have just overlooked it.

            Yes, this is a new pump. I was unable to come up with a workable solution with the other pump and returned it.


            • #7
              My 1953 Shop Manual shows torque specs for pump to block 13-17 ft lb. for 6 cyl.


              • #8
                Have to agree with looks like from your video that the bolt head is not tight against the housing. Sure looks like the bolt may be to long or not seating for some other reason.


                • #9
                  Parts manual shows pump held on with 3 different fasteners. Stud which also holds generator adjusting arm; 1" bolt and 1 5/8" bolt and lock washers.
                  Last edited by rbisacca; 03-26-2019, 10:40 PM.


                  • #10
                    Parts manual is your friend. I had a 63 R2 Hawk with supercharger mounting bolts that were not tight. Turns out the holes were stripped and someone used the wrong bolts and a bunch of washers in an I’ll fated attempt to tighten. After helicoiling the supercharger, I looked up the correct bolt sizes and everything went together good.


                    • #11
                      Tried the Permatex on the bolt but still experienced the leaking. This time, however, it didn't start until I turned the pump shaft. I spoke with the vendor where I purchased the pump and he suggested the weep hole. Sure enough, there's the leak but notice how it runs right over the bolt. That's all I could see from my above vantage point. Hopefully, a third pump will be the charm. Thank you for everyone's input!
                      Click image for larger version

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                      Last edited by Photoguy; 03-29-2019, 03:04 PM.