It works both as re-threading and cleaning up the threads already in the hole. This was similar to the issue I had and fixed it. The tap can create new threads as well higher in the radiator support bracket to better accept the longer TRD skid bolts.

I need to do the same thing with one of my skid plate holes since it was stripped from one of the dealer services way back. Never got to it since I havent had to take the skid plate off yet.

They are normally called plug taps or starter taps because the lead angle never heard of a chaser tap lol. But the angle self-centers the tap and keeps you from cross threading while hand tapping and chasing.
There's also flat bottom taps where if the hole is blind it will thread all the way to the bottom. There's also Roll taps, sti taps but those are irrelevant to this.

Make sure your tap is gh2 or gh3. The bigger the number the looser the fit last thing you want is to chase it with a gh5 or larger and end up with a over-sized thread and have a loose fitting bolt.

And buy a quality tap like OSG I've had to extract out sooo many cheap Chinese taps for people, or broken drills and easy outs from them trying to remove the broken tap its not even funny. Last thing you want is to pack up a cheap tap and snap it off under your rig. They never snap cleanly and its impossible to drill it out with a hand drill and carbide drill bit without destroying the threads and having to install a helicoil or worse snap that drill off in the process.

Sorry for the long winded post 10 years of machining and a slow day in the shop.

Thanks for the response and recommendations. I have never completed this before so I guess I need to watch a couple YouTube videos to familiarize myself with the process.

That's what I did, and trust me, if I can do it you can!

Thank you for this post...I was wondering why it was so difficult to get the supplied bolts on when I initially installed the TRD Skid Plate. After seeing your post I chased the threading per your instructions and now the bolts go on like butter!

Cheers for the post!

Just did this yesterday, worked like a charm and there was a ton of gunk removed!

Awesome write-up bro

It's a good idea for all of us that work on our trucks to have handy the correct sized taps and spare fasteners on hand for the plates. It's just the nature of these types of covers that you can easily misalign while installing and damage threads; even if you are careful to start all of them first. Ask me how I know.

Non-TRD fasteners:

SKID PLATE BOLT 9008011373
LOWER COVER BOLT 9010906330

I just wanted to thank everyone who has posted to this forum. It made my install go flawlessly! When I took the old guard off I noticed the old bolts had some sort of loctite compound on the threads. Also the old bolts had a narrow tip to them (See photo). I found the thread tap at NAPA and reamed the 4 bolt holes to clean the loctite out and fully thread the hole at the proper size. I would not use the old bolts! The new bolts for the back two holes look like they need to be used to reach all the way through the mounting brackets. I applied some anti-seize compound to all the bolts although I'm not sure it is necessary if you ream the holes with the tap. Thanks to all for the help... much appreciated!

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Yep....started noticing same issue about 1 yr ago and been very careful when reinstalling the skid since then. This weekend, one bolt wouldn't screw in properly, so new tap is on order.

I'm trying to remove my OEM TRD skid plate before bringing it to the dealer for it's first oil change.

Looks like I can just crawl under the car and remove all 4 bolts without the 4runner being on a lift.

My question is if I remove the last bolt from the skid plate is it just going to fall off the frame if I don't try to catch it or is it hooked on somewhere to the frame where I can remove all the bolts and unhook the skid?

Yes, watch your head!

Yes, and never sneeze really is your friend so put it on before reinstalling. Just coat the threads evenly, no need to slather it on.

Great thread, who knew?