I was changing the sparkplugs on my 2004 chevy trailblazer and when I removed coil number 1 the bolt broke flush in the coil well. Can anyone tell me the best way to remove it without doing damage. The broken bolt is to far in the coil well to use an easyout.

  • Welcome to Motor Vehicle Maintenance & Repair! Did it break while taking it out or putting it in? Mar 23, 2018 at 21:57
  • 2
    Use a smaller left hand drill bit? Pics of the broken bolt?
    – Ben
    Mar 24, 2018 at 5:37

1 Answer 1


After bad experiences breaking an easy-out I’ve always used reverse (or left, Ben’s answer) drill bits with a tiny bit of a corrosion buster fluid like WD40.

In the US a supplier like Grainger stocks them. I pick one approx. 1/2 diameter of broken bolt, lock into drill, set drill to reverse. Most times the broken bolt backs out as it is being drilled out.

(Tip on purchase, once the supplier was out of the common size reverse drillbit I wanted, but had plenty of others slightly larger/smaller of size I requested.)

  • Also to be safe you can run a tap through the threads after this process to make sure you’re good to go!! Mar 31, 2018 at 14:58

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