I am putting new rotors on and the bolt is stuck on the rotor so I can't get them off. What is the best way to loosen a stubborn bolt?

 

First soak it with penetrant. PB Blaster works great. While it's soaking in, go buy the kind of impact driver that looks like a screwdriver handle, you hit it with a hammer. Clean out the screw head really good so the bit fits GOOD.

If that doesn't work, use a drill. You don't really need that small bolt. The lug nuts hold the rotor on, the little bolt is only for assembly-line convenience.

If you get it off, use anti-seize so you can get it off next time.

 

here's a good way ...

method 1
pb blaster
soak
impact wrench
repeat

method 2
heat the bolt with a torch
impact wrench
repeat

method 2 is what professionals do in rusted bolt situations. whatever you do ... do not ... pb blast and torch. you'll start a fire. if you try method 1 first, clean the surface before you flame on.

 

an inpact wrench should do the trick. driftking was helping me do my rotors and pads a couple of weekends ago and it worked great. no problems what so ever with the impace wrench, the screws came out no problem.