'18 4runner. Was replacing my wife's front pads and rotors today, got the first side done in less than a half hour, second side even quicker and as I go to put in my last caliper mount bolt to finish the job I discover it is cross-threaded. The hole itself ("knuckle"?) where the caliper is bolted to the vehicle, not the bolt itself but the female hole where the caliper mount bolt goes into. The threads are all tore up right at the entrance where the bolt goes in. Cannot get the bolt in, just spins and won't start. So I did some research and saw that a heli-coil repair is an option, but I've never done that before. A couple of questions:

Is there any other trick anyone knows of for this situation to essentially re-thread just the first couple threads on the hole? I can see the damage at the opening of the hole but then further back the threads are perfectly fine.

If I need to go the heli-coil route what is the diameter size I should buy? I keep getting a 1/2 inch kit popping up when I search but I'm not sure of the exact diameter of the 4runner bolts or the size I should get?

Does anyone have a link to a write up or better yet a video on anyone doing this on a 4runner?

Thanks

Is it a small enough section of threads that you could run a tap through and clean them up?

start all bolts/nuts by hand.

Tap. Use cutting oil too. Should clean them up. Turn the steering wheel one way or another to get clearance to get in there.

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As others have said, a tap. But be aware there are two kinds of taps. One has a pointed end and the threads are gradual. Use that kind. The other kind of tap, called a bottom tap, looks blunt and threads start very quickly. It is called a bottom tap for it is meant to tap a blind hole to the bottom.

Is there access on the back side? If so, start your tap on the back, not the front, then it will clean out the bad threads.

Just for your info. Helicoils are weak. Don't use them. It is much better to use a Time-sert which is stronger. (++ TIME-SERT Official Threaded inserts for stripped threads, blown out sparkplugs,).

Before you invest in a tap, you might want to try to make a chaser. Find out what size the bolt is, and the thread pitch as well. Get a new bolt, and use a round file to file a flute, like a tap has, into the bolt. You might want to do two or three flutes. Try threading this in, and it may clean up the threads. Look up Spark Plug Chaser, and it will give you the idea.