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Alternator bracket bolts broke -- special size or type of bolt needed? 5.7 TBI

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  • Alternator bracket bolts broke -- special size or type of bolt needed? 5.7 TBI

    I just replaced the alternator a month or so ago on my '97 190 with the 5.7 TBI. Then today the two bolts that attach the alternator bracket to the engine block broke and left the alternator dangling, still firmly attached to the bracket. Now I have to figure out how to get the bolts out of the block and replace them. My boat stays at the ski lake 45 minutes away from my house, so I am hoping to go back to the lake with the new bolts in hand rather than make a trip just to remove the broken bolts and then a second trip to replace them. Anyone know the specific size/type bolts I need?

  • #2
    Pretty sure they are standard 9/16 UNC about 1" long nothing too special


    • #3
      I had a bottom bolt break at the bracket not the block. Probably much easier. I was able to work the stub out with a hammer and screwdriver. Hope you still have some stub sticking out. Must be something up with that mount system to be snapping bolts. Good luck!


      • #4
        If you can find a Grade 8 bolt that would be best. Mine broke 15 years ago and I replaced it with a Grade 8 bolt and it's never broken again.
        2002, X30, L-18, Red Metal Flake (the possessed boat)


        • #5
          Well that ended up being much easier than I thought it might. There were little stubs of the bolts sticking out of the blocks and simply grabbing them with pliers I was able to easily screw them out. They were indeed 1" long 3/8"-16 hex bolts which I replaced with Grade 8 versions today. Got it done and all back together in time for my brother and I to both get two sets in before sundown. Thanks all for the advice!