Caliper Bolt - removal / seemed "stuck"

So im replacing rotors on 996 (MY1999) and one caliper bolt was wayyyyy to tough to remove for about the first half of the way. i really had to lean on the wrench to get it unstuck, tried some spray to ease it up a bit. Only about halfway out did it get easier. almost looks like the wheel carrier's first few theeads are stripped. (Photo). I had already reattached the other front bolts (other wheel) so i dont have a comparison image. anyone else seen this? ordered new bolts, areived today w a t55 torx/star head so needed a quick trip to buy the right socket.

U r gonna have to dril and tap it for a helicoil. Pretty easy operation, just google helicoil install if u havent done it before.

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thanks for the info, will look further into it. the new bolt went in with no problems, and torqued to 85 Nm, so ill see how it feels on a road test once i finish the rear rotor replacement.

The steel and aluminum alloy set up a corrosion that causes that result. Had one that did similarly on mine recently. The area you see is the worst of it, as the material builds in the threads as it comes out. The threads closer to the bottom are propably in much better shape; hence you were able to torque it to spec. I ran a thread chaser and cleaned the threads of the bolt & all is well.

Well if u got it to bite and torque them u might be fine, but u have reduced the amount of thread engagement. Maybe others will have more insite or opinions.

This is what you need to do: https://rennlist.com/forums/996-foru...ting-hole.html I would not trust the torque to hold given the damaged threads. Keep a close eye on it in case it backs out.

Wow! That's nasty looking. When you have a situation like that, you've got to clean & "chase" the threads at the very least (you didn't mention if you did that or not). If you did this step (clean & chase) then disregard the rest... If not, your next encounter with this bolt probably won't be so successful. By the looks of it, the first few threads are totally gone - this leads to real problems every time you try to "start" /thread the bolt in there (and you probably lose a few more threads). I'm not sure if what we're seeing inside the bore is old/dried anti-seize or chewed up thread material? If it's the former, just shoot some solvent in there (PBB or WD-40 or similar) to clean it up and run your chase/tap (make sure it's the correct thread and pitch) through a few times to make sure there are no old thread chunks left over. If it's the later (actual thread material) you'd have to drill and re-tap to a larger size or do a thread insert (Heli-Coil, E-Z lock, Time-Sert etc...) if you prefer using the stock bolts. ** I always use anti-seize on caliper bolts (steel bolts in an Aluminum caliper) and I try to use the high heat (copper base) stuff on the brakes. Good luck

the timesert kit is truly well developed. If it holds the 60lb ft you're likely fine, but next time you have the caliper off, do the timesert

Timesert vs helicoil every time.. MUCH stronger.. Used them on blind hole mounts on off-road stuff for years.. You can also in some cases just tap to the next size up. Just have to make sure your not taking away structural levels of material. The correct locktight on the timesert is critical don't "make do".. IIRC it calls out the Green-Sleeve Lock,, And always give inserts the full drying time before touching them. With the correct locktight ,, they require flame to remove..

I had a simiar problem removing one caliper bolt. I could only manage 1/8 - 1/4 quarter turn with a breaker bar. Impact couldn't do it. It was hard to remove all the way to the last thread, where I found the end threading of the bolt was pretty bad. I can't tell if the interior hold threads are messed up, and don't want to try and force a bolt in to see. Barring redoing the hole, is there a good way to clean out the threads of any metal and try and save it? I do have new caliper bolts.

Take an angle grinder and grind a slit or two in a used caliper bolt (not the damaged one, obviously) and turn it into the bolt hole. Upon removal you will find the shards collected in the slit. Or use a thread chaser but don't use a thread cutter.

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Can you explain that again? Cut the slit along the threads top to bottom? Not that I have an angle grinder... but curious how this works. And for thread chaser-- https://www.harborfreight.com/titani...ece-61410.html - like that? (This is all new territory).

Yes, from (almost) top to bottom, like shown in the picture the linked harbor freight tap (& die) set is what I meant by thread cutter and is not to be used in this case as it carries a great risk of cutting another thread thereby removing even more material than the damage alone, rendering the result useless.

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Gotcha, I blame the Google. I searched for thread chaser and it returned that How about this? Amazon Amazon

That's it!

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Thread chaser FTW! Used a soft bristle pipe cleaner type thing to clean out the bolt hole. Then slowly ran the chaser bolt through a few times. It scooped up a lot of debris, and seemed to have realigned the threads. New caliber bolt goes in smoothly now, haven't torqued it down yet, but think the chaser saved the day! Thank you!