Announcement

Collapse
No announcement yet.

Advice on repairing a shattered hollow shaft

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • Advice on repairing a shattered hollow shaft

    Hi all,
    I'm hoping someone can give me some ideas on a repair I'm looking to make. I have a pump gear shaft that came from a transmission pump in a 90s era Subaru eCVT transmission that was damaged during reinstall. Parts aren't available new anymore, and used is nearly impossible to come by, and it'd be a real pain to try to re-create it so I'm hoping to repair it.

    ^^^That's a pic of the actual shaft with a pen for size reference. It's some ferric alloy.

    The right hand side in the picture is where the driven gear for the pump is mounted (between the two circlip grooves that are visible). That end is not damaged. The entire piece is hollow to allow ATF to pass through into the pump.

    The left end shattered into 4 pieces. They fit together very tight and there are no other pieces missing. This is the driven end, and it's internally splined to accept the pump drive shaft. It got shattered when the dumb installer (me ) tried to tap the shaft in to seat it.

    At first I thought I'd maybe extend the drive shaft farther into the pump gear shaft and attach it somehow, but there's a problem: The pump gear shaft is cross-drilled for fluid supply to the pump right where it broke off, so I can't block that. Maybe some kind of tube to extend the drive shaft that was also cross-drilled? But then how would I attach the tube to the pump shaft?

    Similarly, I thought about an external sleeve that held the pieces in place. It would have to be thin, though, as the shaft extends into a hole in the transmission and doesn't have a lot of clearance, and I'm also not sure how I'd attach it.

    Other than that I thought about reattaching the pieces. I've had heat cured JB Weld suggested but I can't imagine it having enough strength to handle the torque and vibration, but then I've never tried it in a situation like this. Other high-tensile strength epoxies have been suggested but they're hard to come by and I'm still not sure if it'd work.

    I've thought about getting it welded but I'm worried about the heat causing problems.

    Silver soldering would be ideal, I think, but how would I hold the pieces in place while soldering?

    Anyway, that's as far as I've gotten in finding a solution. Obviously I'm kind of stuck. Anybody else have some idea how to pull of this repair?

  • #2
    Is this it ?

    http://parts.subaru.com/p/Subaru_201...1359AA240.html
    .

    Sir John , Earl of Bligeport & Sudspumpwater. MBE [ Motor Bike Engineer ] Nottingham England.



    Comment


    • #3
      Hi John,
      Nope, that's not it. This would be closer:
      http://parts.subaru.com/p/Subaru__Ju...1340KA110.html

      That's from a Justy of the same year but depending on who you talk to the pump is the same or somewhat different, and I haven't been able to get a picture of the actual part to know for sure. The service manuals and most parts diagrams show slight variations even for the same vehicle (ie. the length of this shaft and it's shape), so it's possible they changed design mid-production due to issues. In either case according to Subaru the part is unavailable.

      The actual vehicle is a Subaru Sambar, which is a JDM (Japanese Domestic Market) vehicle so the parts aren't readily accessible outside Japan.

      Comment


      • #4
        Hi,

        I would not try to repair that. You will not be able to get the inside and outside to ever match what is originally was. It won't ever be trustworthy. Either make a new one or buy one.

        Dalee
        If you think you understand what is going on, you haven't been paying attention.

        Comment


        • #5
          Originally posted by dalee100 View Post
          Hi,

          I would not try to repair that. You will not be able to get the inside and outside to ever match what is originally was. It won't ever be trustworthy. Either make a new one or buy one.

          Dalee
          As mentioned the part isn't available to buy, otherwise I would have. As for making it, that's a lot easier said than done - it's a complicated part and the section that's OK contains multiple precision ground bearing surfaces that I can't replicate in my shop.

          I'm fairly certain silver solder would work if I could hold the pieces in an assembled position while soldering, but I'm not sure how I'd do that. The tolerances are so close the joint strength would be incredibly high, which isn't really needed anyway as it's just driving a pump.

          I think it makes sense in this case to try some sort of repair as the part isn't available and the only other options are scrap the vehicle or convert to a different transmission, which brings it's own problems. There's no safety concern as if it breaks it just means the vehicle coasts to a stop.

          My biggest question is what the best method to try would be, thus the post.

          Comment


          • #6
            Originally posted by JoeBean View Post
            Silver soldering would be ideal, I think, but how would I hold the pieces in place while soldering?
            Find a short length of spring slightly smaller in diameter and slide it over the pieces as you hold them together.
            Location: Long Island, N.Y.

            Comment


            • #7
              Hi,

              Seriously, look for a used one then or start from scratch. This won't go back together in a satisfactory manor. Silver solder will not work well because you will ruin the heat treat, (from the failure it looks hardened). Plus you do need enough space between the broken parts to make room for the solder. Normally, that runs from .002" to .006" clearance per joint to allow the solder to fill and bond. I regularly make parts that are silver soldered together. This is the engineering requirements for best strength. Your finished job will be too big. Nor will the solder be happy about the radial forces it needs to endure during operation. Any electrical welding, MIG, TIG, or stick, will lead a HAZ that will be subject to fast failure.

              This isn't a repair job that can have a decent chance at success. Sometimes we just can't fix it.

              Dalee
              If you think you understand what is going on, you haven't been paying attention.

              Comment


              • #8
                Pretty much what Dalee said...that part is history.
                Fall back and regroup.
                Chances are there is a solution for someone w/ ingenuity and some machine tools, but without seeing what you're up against, no suggestions.

                Comment


                • #9
                  You said a thin sleeve would work so why not make a sleeve and silver solder the broken pieces and sleeve.
                  Jon

                  Comment


                  • #10
                    Originally posted by JoeBean View Post
                    As mentioned the part isn't available to buy, otherwise I would have. As for making it, that's a lot easier said than done - it's a complicated part and the section that's OK contains multiple precision ground bearing surfaces that I can't replicate in my shop.
                    ......
                    Lessee... Part not available in any way. Part uneconomical to make. Part too shattered (and distorted by the shattering) to repair without basically remaking it.

                    Yer screwed.

                    That's how cars get towed to the crusher.

                    A prime example of the reason behind the saying "if you can't fix it, you don't own it".
                    CNC machines only go through the motions

                    Comment


                    • #11
                      Originally posted by JoeBean View Post
                      There's no safety concern as if it breaks it just means the vehicle coasts to a stop.
                      One of the car manufacturers was sued for that a few years ago. I think someone died. Car stopped in the middle of an intersection. Maybe you can make it and get someone else to grind it?

                      Comment


                      • #12
                        The part is likely a heat treated high strength steel alloy, right? So which of any of the options mentioned so far do you think will match the different strengths of the original steel? The right answer is "C)-None of the above." The part is toast.

                        Welding will cause damage to the heat treatment of the metal and would result in significant distortion in any event. And silver soldering or brazing won't be much better since the part will be over size due to distortion from stretching around the crack lines and the need for at least a minimal amount of the silver solder or brazing in the cracks.

                        Bottom line is that that this item is toast and you need to look around for someone with a good condition used one at some wrecker. Discussion boards on such orphaned vehicles is often a good place to start. Or suck it up and look at making one and then having it heat treated correctly and possibly finish ground to size by a shop.

                        As for the bright one that suggested JBWeld? Well, the depth of misunderstanding of the limits of glue just boggles the mind. You were right to doubt that one right off the bat. I'm constantly amazed at the reputation that JBWeld has in the minds of some folks. JBWeld is just epoxy with a metal powder filler. It's a GOOD epoxy for sure. I've used it on occasion myself. But the "Weld" part of its name is taken far too seriously by far too many.
                        Last edited by BCRider; 11-09-2016, 01:06 PM.
                        Chilliwack BC, Canada

                        Comment


                        • #13
                          Originally posted by dalee100 View Post
                          Hi,

                          I would not try to repair that. You will not be able to get the inside and outside to ever match what is originally was. It won't ever be trustworthy. Either make a new one or buy one...
                          Yup, you are never going to repair that in a way that's functional. I have spent the last 45+ years making and fixing things for a living--and over that time have fixed some pretty hairy stuff--but given the extent of the damage and what that has to do it's not a candidate for repair. Getting everything aligned, all the surfaces smooth and holding the thing together is virtually impossible...
                          Keith
                          __________________________
                          Just one project too many--that's what finally got him...

                          Comment


                          • #14
                            Make a new one.
                            As my Auntie Shirley used to say "It's a learning and growing experience" ;-)
                            If you benefit from the Dunning-Kruger Effect you may not even know it ;-)

                            Comment


                            • #15
                              Originally posted by BCRider View Post
                              ...As for the bright one that suggested JBWeld? Well, the depth of misunderstanding of the limits of glue just boggles the mind. You were right to doubt that one right off the bat. I'm constantly amazed at the reputation that JBWeld has in the minds of some folks. JBWeld is just epoxy with a metal powder filler. It's a GOOD epoxy for sure. I've used it on occasion myself. But the "Weld" part of its name is taken far too seriously by far too many.
                              I so agree with what you're saying. JBWeld is so over-rated and so misunderstood by so many people. I would rate it as a decent epoxy but there are many industrial epoxies out there that are much better. You must know the limits of any epoxy before you use it. While they may not work as a proper fix for a lot of things they still stick like **** to a hair and when someone brings us a part that has been "fixed" with JBWeld or one of it's cousins it's still a royal pain to clean things up before you can make a proper weld...
                              Keith
                              __________________________
                              Just one project too many--that's what finally got him...

                              Comment

                              Working...
                              X