it sounded like the brakes were grinding

Hello,

When the caliper gets stuck with the piston extended it will cause the brake pads to run against the rotors. When the metal wear indicating tab contacts the rotors it will make grinding noise as you are driving.
Usually this can be due to a faulty brake hose. The rubber hose that is attached the caliper can collapse on the inside and that creates restriction for the fluid to travel. As the brake pedal gets released the fluid is unable to go back thru the hose, which leads to caliper sticking.
When a brake sticks, it will create excessive heat.

Any time you have brake sticking issue, it is best to replace both caliper and the brake hose, along with the pads and rotors.

https://www.2carpros.com/articles/brake-caliper-replacement
https://www.2carpros.com/articles/how-to-replace-front-brake-pads-and-rotors-fwd

I have attached diagrams for your reference.

Please let me know if you have any questions.
Thank you.