Caliper mounting bolt - stripped threads in mount?

Unable to get the upper caliper bolt to thread down tight. Goes about half way in and binds up tight. I tried the lower bolt and hit hard resistance at the same depth. Bolts both look fine. Of course, I have no lift so I can't really see anything much.

Assuming the bolts are fine, is that the lower control arm/steering knuckle(?) they thread into to mount the calipers? And, whatever that part is, think running a tap into it would give me a shot at getting things back to normal?

 

I currently have both of my 2012 Tacoma calipers off during a complete brake job. My upper and lower bolt holes you can see completely through them if the rotors are removed. It's not a blind hole. Spray it out with brake cleaner and try again. Sounds like a restriction. I'd go that route before running a tap through it. What year is your Tacoma?

 

Also is the bolt holes go all the way through you can try and run the bolt or a tap through the other way.
You need to see if there is anything restricting the bolt is if its just slightly messed up threads.
You can always spray the holes down with penetrating oil and run a small round metal brush through it to see if that makes it any better.
There is always the not great idea of using a impact wrench and hoping the impact/bumping will help move the bolt through whatever is in the way.

 

Thanks! Well, of course the problem came on the last bolt before putting the tire back on. Put some pressure on it with a breaker bar, it turned another full turn, but then starting hearing that ominous popping sound (like trying to loosen lugs someone hit with a big impact wrench). Will remove it all and take another look from the front side, try running the bolt in from the opposite side, etc. Will report back what I find or end up doing. Thanks, again.

 

Agree, remove rotor, install bolt backwards through to clean threads. Lots of lubricant.

 

I’ve done the same on a motorcycle caliper mount and successfully used a Heli-Coil to repair the threads.

 

Yep, heli-coil is the fail safe option -- hoping to get lucky. Thanks.

 

You need to run a tap through there and clean the threads. Run your bolts through a die if they're boogered up.

 

I’d definitely go with running a tap through it.
If you are 4WD or PreRunner, I believe those bolts torque to - 91 ft/lb
I’d want the threads on both the bolt and knuckle to be as good as possible.
I also like to use a bit of blue (medium) loc-tite.
Because it makes me feel better. LOL

 

91ft./lbs. is correct. Now, just gotta get other stuff out of the way today before I can get back to it!

Thanks.

 

Never do that with a sticking bolt. It only makes it worse.

Did you have problems removing the bolts?

 

Run a correct tap through the hole,well oiled after you clean the area up.

 

Okay, ladies and gents, here's the rest of this story.

About a year ago, I replaced both front wheel bearing assemblies. Evidently, with no one else to blame and despite my habit of double-checking everything I do, I failed to notice that the top caliper bolt on one side was not seated. Gulp!

So with that bolt only part way through the caliper mount, rust, etc. built up and gummed up the threads. Who knows, maybe the problem existed when I removed that bolt, but whatever the reason that kept it from going in all the way.

Now, to be responsive to all of the comments here (other than the ones to come about what an idiot I am, LOL), bearing down on that bolt with a cheater bar for a full turn (as posted above) was NOT a good idea. It did make it worse, and I barely got the thing off again just now. But, it came out, and I rented a kit from AZ. Gradually worked the M12 x 1.25 chaser tap in and out, cleaning and oiling as I went. Got it all the way through with gunk on the end. Ran it through the lower mount hole, just for good measure. New caliper bolts, and the job is done.

Gotta say, as always and once again, I so appreciate all the generosity of the folks on this forum. It's the best, and thank you for steering me straight, despite my idiocy. Moving to a triple-check strategy from here.
Now, let the tomato throwing begin....

 

Good job and thanks for closing the loop on this one. We all make mistakes. The important part is that you learned something from it. My son once said, "Sometimes the burned finger is the best teacher." Wise words from a teenager.