Problem Breaking Self Tapping bolts when remove old ones

Discussion in 'Mechanic and Repair' started by Rain Man av, Apr 1, 2008.

  1. Rain Man av

    Rain Man av LawnSite Member
    Posts: 133

    Time after time I am unable to remove self tapping bolts. More often than not they break off.

    Two cases I refer to....

    1) Spindle Deck assemblies - Alum housings with steel self-tapping bolts. Most mandrels aka spindles have four bolts. There is always that one bolt that brakes, and in some cases two.

    2) Mounting bolts on B&S engines - This is probably more important than the case above. heat/ice, solvents, penetrating oils, etc to no avail.

    When I put them back together, or when I'm installing new, I always put anti-seize on the new bolts before threading, this way whoever may end up with the lawnmower after me, will have better success - Pay If Forward.

    I've tried heating with propane torch -the kind plumbers use to solder pipes - followed by melting ice against the bolt head in hopes of freeing the bolt.

    I've tried all kinds of penetrating oils and solvents - those so-called - bolt breakers - with no luck what-so-ever.

    I've tried those reverse drill bits and ease-outs. The ease outs almost always break causing me to take two steps back. The reverse drill bits, although they drill a hole, they have never gotten the remnants of the bolt out.

    Who has a tried and true way of pretreating these kind of bolts without breaking them off?
    Getting them out after breaking them off?
    Is this just a pipe dream on my part?
    Wishful thinking?
    Or a fact of life?

    S DIAMOND LawnSite Member
    from South
    Posts: 108

    EZ-Out and "left handed" bits are a crap shoot. Sometimes you when, sometimes it's the house. As far as removing bolts at the point of no return, Cobalt bits are the only way to go. IMHO.
  3. larryinalabama

    larryinalabama LawnSite Fanatic
    Posts: 17,033

    It might be worth while to invest in some Heli-coil kits.
  4. Jay19LM

    Jay19LM LawnSite Member
    from Mo
    Posts: 31

    I lay a washer or nut over the broken off head and mig weld right on the end of the bolt. Sometimes I will weld right on the end of the bolt. I build it up enough to grab with a pair of small vise grips. Only takes a minite and they come right out. Just be carefull not to overheat the aluminum.
  5. kayeproperties

    kayeproperties LawnSite Member
    Posts: 141

    I have that bolt breaking problem on everything I ever work on it seems! Does the mig welding heat it up so it comes free? How bout the ones that break in the hole? Id love some ideas on this subject is I am afraid to take things apart until They break for fear of broken bolts and having more of a problem.
  6. Restrorob

    Restrorob LawnSite Fanatic
    Posts: 11,023

    I never remove a aluminum mandrel on box store units (with self tappers) unless I'm replacing the whole assembly, I install shaft/bearing kits without removing the whole deck from under the unit. If I'm replacing the whole assembly I put my big impact on the screws and let it rip, If they break they are replaced with standard screws.

    I have square drive sockets that fit taps and my small impact in which I tap all new assemblies before installing. Broke a self tapper in a new assembly once by hand, Never again.

    As for engine mount screws, I don't recall having one break. I spray with PB-Blaster a few times through out the day then once more before leaving. Come in the next day and put a old deep Taiwan socket on the head (most all have the washer area on the head) and smack it a few times with a hammer then screw it out.
  7. sawman65

    sawman65 LawnSite Senior Member
    Posts: 751

    first if you can get it to move at all rock it back and forth losen,tighten it will come out sooner or later. then their is a trick my dad showed me, get a candle and melt some hot wax onto the bolt get enough on it to cover it clean it off and do it again.something about the oil in the wax. it will get down into the threads i have used this on many exaust system bolts it work like a charm. works on those pesky 8mm bolts that hold the covers on kohlers too they break all the time. old school methods sometimes work when all else fails.
  8. Tim Johnson

    Tim Johnson LawnSite Member
    Posts: 135

    Great tip, I'm going to try that wax idea out.

  9. jkason

    jkason LawnSite Senior Member
    Posts: 548

    Wax may work - I'm going to have to try that.

    As for getting the bolts out easy after they have benn in for a while - forget it.

    Drill slightly oversize and use a regular bolt and locknut (with washers) if you want to save money.

    Or replace the whole thing and use new bolts - the way I do it for my customers.
  10. Rain Man av

    Rain Man av LawnSite Member
    Posts: 133

    Guys, you all rock. Thanks for your feedback. I will keep all of them in mind, I have a deck with spindles I need to replace. If I run into any stubborn bolts, I'll try these and let you know how things turn out.

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