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'61 Hawk Fuel Sending Unit: Machine Screws, Cork, Part# Match

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  • Fuel System: '61 Hawk Fuel Sending Unit: Machine Screws, Cork, Part# Match

    I read all related posts, but didn't find answers to my 3 questions regarding replacing faulty fuel sending unit on my '61 Hawk. (1) Previous owner installed sheet metal screws. Is it worth re-taping the holes to fit machine screws, and if so, what thread size is preferred? (I presume the hole/thread size will have to be larger than factory specs.) (2) I acquired a NOS S-P part #1-1544825 sending unit (for '58 Hawk). I don't find any differences between it and original part #1-1549575 except the hot wire post, which actually better matches the hot wire on my car anyway. Both are 12 V, same hole configuration. Is there a problem using this part produced for the '58 Hawks? (3) Lastly, the cork on this new part is pristine. It still has shellac, but I am coating it with "Seal-All" sealant over that. "Seal-All" is "oil and gas resistant" according to the product description. Will that keep the cork buoyant for awhile and not dissolve into my fuel tank? Thanks in advance to you technical and hard knocks experts, I appreciate your advice!!

  • #2
    Because Brass and Plastic Floats are available I don't recommend the Old Style Corks due to the Ethanol in most Fuel. The Sealer may take Gasoline but what about Alcohol?

    The Fit should be fine as long as the Float Arm faces RIGHT when the Hole pattern in the Sender is matched to the Tank, as you know it is NOT symmetrical.

    Never Tried or heard of "Seal All", so don't know about that.
    If the installation gives you any trouble working correctly, you can always add a Ground wire from a Sender Mounting Screw to the Frame.

    Sorry, I do not know the Machine Screw size, I always match New ones to the original from stock, so no idea.
    Second Generation Stude Driver,
    Proud '54 Starliner Owner


    • #3
      If the original screw holes in the tank are stripped, might have to use next size up, and drill the sender holes to accommodate the larger screw. I'd get some original screws and try them first though, as they might be OK. I agree with you in using the cork float, and like your idea of coating it with something impervious to gasohol.


      • #4
        Seal-All is a clear viscous cement that comes in a tube. It is definitely resistant to gasoline, and I have "patched" leaking gas tanks with it. It's very old product. I don't know if it is resistant to alcohol. But even assuming that it is, getting 100% coverage of the entire float is going to be a chore. I sure would recommend going to a metal or alcohol-resistant plastic float.

        I think the original sending unit screws were 8-32, possibly 10-32. If a 10-32 screw fits through the hole on the new sending unit, then that is the correct size. If it's a no-go, then 8-32 is the one. If the holes in the tank are wallowed out, and the proper screw size does not fit, then you could drill and tap the tank to the next larger size. There is a thick metal reinforcing ring that holds the threaded holes.
        Gord Richmond, within Weasel range of the Alberta Badlands


        • #5
          I just did this last Monday. My sender would not seal because someone before me installed it with sheet metal screws and you just couldn't get it tight enough to seal. I repaired the tank by making this, 5 hole stainless steel "nut" to replace the missing threads.
          Click image for larger version  Name:	IMG_1392.JPG Views:	0 Size:	82.5 KB ID:	1836376
          The cut in it allows you to get it into the tank, then the two 4-40 flatheads hold it in place, (through holes i drilled) until sender is installed. I drilled the original mangled holes out for clearance. It is threaded for 10-32. I have several working original type senders, but my gauge responds too quickly for them, so it's constantly moving reading "slosh", so I replaced the sender with one that works vertically and has no arm. The tank is only 5" deep and my sender is 6" tall so I made a spacer to lift it which made it extend a bit higher than the trunk floor so had to make a raised cover plate. it works great!
          Click image for larger version  Name:	IMG_1404.JPG Views:	0 Size:	114.8 KB ID:	1836377Click image for larger version  Name:	IMG_1411.JPG Views:	0 Size:	100.3 KB ID:	1836378Click image for larger version  Name:	IMG_1414.JPG Views:	0 Size:	90.7 KB ID:	1836379


          • #6
            Wow! THAT is a LOT of Very Nice Custom Work, but if you are not a machinist it won't happen.

            Pulling the Tank, drilling out the Sender and the Tank and re-threading oversize would be the "backyard Fix" and probably Faster.
            Second Generation Stude Driver,
            Proud '54 Starliner Owner


            • #7
              Studebaker sending units are not unique, there are after market solutions already available...... I do like the creativity though


              also available in stainless...then there's this



              available in many sizes....

              Last edited by Captain Billy; 05-18-2020, 04:29 AM.
              Bill Foy
              1000 Islands, Ontario
              1953 Starlight Coupe


              • #8
                These are all fantastic insights and comments, thank you. The float arm does swing the correct way, and by the absence of any comments regarding the electrical elements, I am understanding the part # of the new sending unit I found will work. That's 90% of what I was hoping to hear. I actually toyed with the idea of replacing cork by bending the float arm wire and soldering a Ford brass canister to serve as a float (as recommended on other threads). And, I practiced on an old unit.... and because the wire is a little more challenging to bend than I wanted, I figured I don't want to mess up a NOS item like I have, and will try the coated cork for awhile. If it fails (or maybe "when"), I resort to the brass canister option. I appreciate the thread count options, and so I will "mask up", head to the hardware store, and will see if I can get several sets of 5 screws and see if they still fit, oh, and some crush-able washers too. I have some fiber washers that I got from SI when I bought the aftermarket sending unit a number of years ago from them (Mexico made). It may be that the problem is grounding, or something else, but the seal is leading and starting from scratch is the way to go, and I am too old to just leave a NOS sending unit in my replacement parts cabinet..... time to upgrade. Thank you all for your thoughtfulness.... and stay safe!


                • #9
                  Thought others may benefit to see the result of the application of "Seal All" to the cork. I really like the result, though untested yet (of course). I think it would be resistant to alcohol as well (an educated guess), as they promote this product for applications for gas cans, and we have "enjoyed" (ya right), formulated fuel for quite a long time now, so I think a good chance it works with that in the mix as well.

                  Also, want to thank and commend "Bensherb" for the creativity and skill of that solution. It is beyond my paygrade, but I love the idea of solutions that go beyond the tried-and-true and into the realm of ..... "never thought of that". Hats off to that one. Wish I took machine shop back in the day.


                  • #10
                    Captain billy: The Tanks inc repair nut/ split ring is great! I never even thought of looking for such a thing, just figured I'd have to make one like most everything else I need. The sender from amazon is very much the same as what I used, but mine was WAY cheaper. Yep, CASO here; I prefer PASO (poor not cheap).

                    The sender I used was the shortest I found. True, I am a machinist and have a small garage shop, but, my spacer could easily (relivively) be made with a hand drill, hole saws and a drill bit, and probably take less time to make (depending on the material you start with) ; but it won't be as pretty. Yea, I'm bad that way. It has to look good even if you can't see it. Those double nuts are still bugging me, but it's all I had at the time. There are no decent hardware suppliers around here, so online orders and horid shipping costs it is.

                    Thank you Badger. I never took "machine shop" either. Took wood shop instead. Worked as a cabinet maker until I developed an alergy to wood dust ('89). I tought myself machining but did get a job as welder in a machine shop (certified welder since '82) and worked it into being a prototype machinist. Funny thing is my degrees are in electronics ('79-'82 hated it) and sociology.


                    • #11
                      I read somewhere to coat the cork with super glue because it was alcohol proof. I repaired mine this way two years ago, so far it's working good.


                      • #12
                        Sort of a post script about the results given all the great advice you generously shared. As to re-tapping threads for machine screws, I found that the lack of alignment between the access hole in the trunk with the fuel sending unit mounting hole, prevented me from using a tap to re-cut threads in 3 of the 5 holes, so that was a no-go and I have accepted the reality that sheet metal screws will have to do. As for the Seal All, after letting it dry or a full day, I gave the cork a second coat. By the way, it flows easily from the tube, I did not use a brush, just gravity to move it around the surfaces. Be aware, though, it does dry in a few minutes. I then waited another full two days before submerging the float. If it holds, it is an amazing product. It definitely encapsulated the entire portion of cork & wire. It started out as a fairly thick skin, but it thinned as it dried and it definitely lightened up (I was worried it would weigh down the cork). There are bubbles in the dried coating as you can see in the photos, but they are not weak spots. I tested it after the first coat, this product is tough! Lastly, I had trouble easily locating copper crush washers (or maybe just impatient), so I used some fiberous ones that I got from SI quite a lot time ago when I changed the gasket many years ago. Anyway, it worked well so far, and if it fails, I will replace the cork with a plastic float that was on the failed unit I just removed. See you on the road!


                        • #13
                          I sealed the float in my M16 a couple of years ago with Seal All. I just took it out of the tank last week to check on it and it was still in perfect shape. The stuff works good and is definitely alcohol resistant. As far as the sending unit screws go, I believe that the sheet metal screws are the original screws that Studebaker used. My M16 uses them and SI used to sell a sending unit screw kit that had 5 stainless sheet metal screws and five small copper seals. Last year I ordered another kit from them and it had machine screws and standard lock washers. Not sure what these will fit.

                          Roger List
                          Roger W. List
                          Proud Studebaker Owner