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Motor bolt broken

Discussion in 'Fisher Engineering Discussion' started by allen81, Jan 24, 2012.

  1. allen81

    allen81 Member
    Messages: 97

    Please see picture of the bolt head that I broke. Also on the ground side of the motor is there a way to put a new stud in or do you have to replace the motor.I will post a picture of the ground stud if anyone is not sure what one I am talking about. Any help is greatly appreciated

    [​IMG]
     
    Last edited: Jan 24, 2012
  2. mrv8outboard

    mrv8outboard Senior Member
    Messages: 197

    If the bolt pictured is the one with the red wire under it you are referring to, that is a 1/4"x20 bolt utilizing a 7/16" head. That bolt goes through the valve manifold. The manifold is aluminum and corrodes around the bolt. I have one on the bench I am going to service that has the same issue. Take your time. Remove the unit (best way). You have to loosen the bolt in the corrosion, try the nut on the under side, loosen a little then try to drive it up. Now tighten the nut to pull it back down, repeat. Do not forget to use a penetrating oil. You will now effect the corrosion with it but it helps the process. Once it is out use a drill bit to clean out hole. Replace the bolt.

    Now to keep it from happening again I use "Mercury Perfect Seal" a non hardening gasket sealing compound on the bolt and in the hole, but use some thing.

    The ground stud you refer to is the motor housing ground and not the B- that connects to the B- terminal on the motor like the B+ does? If so you would have to know how to remove the broken bolt with out damaging the motor. But the motor's mounting bolt would be the better second choice for the ground.
     
  3. 06Sierra

    06Sierra PlowSite.com Addict
    from Maine
    Messages: 1,329

    Get some sea foam deep creep. I have had really good results using that to free up rusted nuts and bolts.
     
  4. allen81

    allen81 Member
    Messages: 97

    I am able to loosen the bottom nut with no problem at all so spray some penetrating oil and then try to hit it from the bottom up.
     
  5. kimber750

    kimber750 PlowSite Veteran
    Messages: 3,679

    Little bit of heat will go a long way. Just be very careful not to heat it too much. I am guessing you snapped the head off the bolt so use a small punch after heating to tap the bolt down thru.
     
  6. allen81

    allen81 Member
    Messages: 97

    Yes the bolt head broke off. Now what about the stud on the motor where the black wire goes is that stud able to back out of the motor? That is where the black/orange stripe wire use to go.
     
    Last edited: Jan 24, 2012
  7. allen81

    allen81 Member
    Messages: 97

    I do have my parking and turn signals working I drilled a hole and bolted the black/orange stripe. But I would like to replace the positive and negative studs if possible. The positive one seems like when I am loosening the nuts the stud is turning I am just wondering if the same thing will happen on the negative stud?
     
  8. kimber750

    kimber750 PlowSite Veteran
    Messages: 3,679

    I do not know if you can replace the studs on the motor or not. Neg maybe, Pos I doubt it, since the Pos should have a wire going to the brushes. But I have never taken one of these motors apart, have only replaced them.
     
  9. buddymanzpop

    buddymanzpop Senior Member
    Messages: 601

    The ground stud can be replaced with a hex head bolt, you will have to grind the head down a bit to make it fit properly, your lucky, that is one of the easier motors to take apart and put back together, the brushes are right under that flat disc cap on top, Allen, after you get it back together don't let the armature slide out, because that's all it wants to do and you have to reset the brushes again.
     
    CaliO likes this.
  10. TJS

    TJS PlowSite.com Addict
    Messages: 1,343

    I have never used a drill or eazy out yet to extract any broken bolt or stud. It just causes more problems. I weld a nut to the broken bolt/stud and let the heat do its work. I had a insta act manifold block where all the bolts were broken flush, even the motor mounting bolts. Took it all apart and removed all poppets/valves and such cause of the O rings. Got them all out in 20 min and 8 nuts later.
    T.J.
     
  11. allen81

    allen81 Member
    Messages: 97

    What good would it do to weld a nut when the bolt head broke off flush, someone said to spray it with penetrating spray and drive it out with a punch,
     
  12. TJS

    TJS PlowSite.com Addict
    Messages: 1,343

    Go for it then.
     
  13. kimber750

    kimber750 PlowSite Veteran
    Messages: 3,679

    The bolt circled in the picture is not threaded into the pump. Only thing holding the bolt there is corrosion, not threads.
     
  14. TJS

    TJS PlowSite.com Addict
    Messages: 1,343

    Yup, now I see. If he ever goes to remove that motor, the bolts will break. Many Insta acts leak water down the motor and it sits on the manifold block and corrodes. This is why these things need a real cover not just the so called motor cap.