What size bolt screws into a brake rotor to remove it?

Doing a BBK upgrade on my 2008 X-Runner, and was surprised the calipers bolts came out without having to use an impact gun, but my rotors have been on there since new, and they do not want to release off the hub.

Need the bolt size to screw into and through the rotor to remove it from the hub.

Thanks!

 

The bolt size is a 4lb hammer and some percussive maintenance.

 

Should be an 8x1.0 or 8x1.25 i beleive. Basically a 12mm bolt

 

It is an 8x1.25

 

8 x 1.25

 

8x1.25

But normally you can just whack them with a deadblow or something equally heavy and they'll break free. I always coat the mating surface of my drums and rotors with anti-seize to prevent this.

 

Thanks to everyone! I was in Advance Auto looking at bolts, and was going to buy a couple different sizes that looked close in size. This saved me at least $10.

 

I was whacking the rotor with a deadblow, then a ball peen hammer, then gave up and decided to ask the question here about the bolt size. Should have the first rotor off in a couple of minutes.

 

Don't forget to clean up the hub face with a wire brush, and use a generous glob of anti-sieze paste or something on it.

 

Ehhhh if it’s a second gen it’s a pretty old truck now haha. I hit mine for 5-10 minutes with mallets and hammers until I realized the bolt trick lol

 

The key is to not be too ginger with it. I find a 4lb hammer does the trick pretty well. Smack, rotate, and repeat. If it's not coming off, smack harder lol. Mallets, dead blows, and regular 16-20 oz hammers typically don't cut it; need more oomph.

That being said, using a bolt, especially with an impact will do just fine, just takes longer IMO.

I used to do the bolt method every time on my vehicles, now I'm older and lazier and I just grab the 4lb hammer right off the bat.

 

Normally you can
But if a person is not good at whacking. They might whack off more than intended.

 

Ball peen or dead-blow isnt going to cut it. You need something like at least 2-3 lb with a short handle

My trusty BFH from Matco - 1.8 lb/ 10 inch handle

 

True, if you whack off more than you intended there can be problems with chaffing. Not to mention the mess.

 

I guess I should specify that my deadblow is 40oz. It hasn't met a rotor it can't take off yet, but I don't deal with rust much.

You can whack the shit out of them though since you're discarding the rotors lol.

 

I cleaned it up, then put a light coat of grease where it contacts the rotor.

Finished product (except for hitting it with brake clean):

 

I whacked it for about 10 minutes, but the bolt removed it in about 30 seconds. That definitely works faster for me...lol

 

The horn bracket has the same size bolt
That what I used on mine then just reattach bracket

 

But did you use a 4lb hammer?! Lol, glad you got it done!