Rounded bolt heads

I am changing rotors on a 2000 ford mustang and the bolt that holds the bracket on is rounded i have tried heat and even bought a bolt grip tool to no avail any suggestios would be greatly appreciated

Well, there are some different approaches to this problem. I have had luck filing or grinding some flats back on to the bolt head and then trying to “fit” either the next smallest socket on to the bolt head. “Fitting” tends to involve beating with a hammer. If it’s an SAE (“American”) bolt, try the next size down, and if that doesn’t work, try a similar metric size. Granted, you’re probably going to have to buy a new socket when it’s all said and done, but don’t give up.

In addition to what Mr Josh has well described, I would add to use plenty of PB Blaster penetrating oil or similar on the fastener and allow time to penetrate. The longer the better.

What bolt? What bracket? Are you referring to the bolts that hold the yoke to the steering knuckle?
Have you been using metric sockets on this or others that appeared to be close enough?

I assumed he was talking about the caliper mounting bolts. Do you have to unbolt the caliper to pull the rotor on a mustang?

As far as I know, the entire caliper and yoke assembly has to come off. The yoke bolts should be hex heads, but the caliper bolts have round heads and are either Allen or Torx heads.
Removing the caliper only won’t allow removal of the rotor so I assume he means the yoke bolts.
The caliper bolts look like this.

It’s a bit unclear to me if he’s wrestling the caliper bolts here instead of the yoke bolts.

If he means the hex head yoke bolts then I was curious if an SAE standard socket or wrench had been used on a metric bolt head. There is no exact match between SAE and metric although some sockets can be interchanged and used if the bolt is not stuck. A 1/2" socket will remove a 13 MM headed bolt but the half is actually a bit larger than 13 MM so it’s possible to round a bolt head off that way.

I got the caliper off now I need to get the as you called yolk bolt off it is a hex head but it is a 15mm head it does not have a hex head for an allen wrench just a hex head for a socket the head is completly rounded I used the grip tool,vice grips and even a pipe wrench have heated and penetrated to no avail the bolt does not want to budge