Installing heli-coils with the head on is not a good idea UNLESS you isolate the area & have a shop vac to suck away the debris as you drill & tap.

WE use Time-serts instead of heli-coils as they "hold" better. A 8mm kit comes with all of the needed tools except the drill motor.

Make sure to use NEW bolts 8 x 70 MM that are 10.9 hardness.

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