So I recently replaced the brakes pads on my Vehicle. After I did the change I drove it around my Neighborhood for a short time. I got back to my garage and the Rotors were super hot. Which I have done pad changes before and the rotors always seem to get hot during the break in process from Pads to Rotors. But how long does it last? (The brake in process) and Would it be safe to drive an hour or more the next day on the Highway (70+MPH) after replacing the pads??
Perfectly safe, if the brake job was done correctly. Heat is fine - the pads will be burning off the anti-rust coating.
Remember to bed the pads in correctly; the following content is not mine, it's from http://brakeperformance.com/bedding-in-rotors.php
Perform 3-4 medium stops from 45mph. Slightly more aggressive than normal braking. You don't need to come to a complete stop for each pass. This brings the brake rotors up to temperature so they are not exposed to sudden thermal shock.
Make 8-10 aggressive stops from 60mph down to 15mph. For this set of semi-stops, you want to be firm and aggressive, but not to the point where ABS activates and the wheels lock up. It's important to note that you don't come to a complete stop but rather a semi-stop (~15mph). Accelerate back up to 60mph as soon as you slowed down to your semi-stop.
The brake pads and brake rotors are extremely hot at this point and sitting on one point will imprint the pad material onto the surface unevenly. This can cause vibration and uneven braking.
You may notice that your brakes will start fading, and sometimes smoke, after the 6th or 7th pass. This fade will stabilize and will gradually recess once your brakes have cooled down to normal operating temperatures. Drive carefully as your brakes may feel softer for the next few minutes.
Try not to come to a complete stop and find a stretch of road where you can coast for 5-10 minutes, preferably without using your brakes.