First post and forum virgin. This is the second day (not in a row) that I've been driving interstate and my right front passenger tire has been squealling/grinding and then it almost sounds like a hydraulic pressure noise when I slow down to pull to the side of the road. It's an awful noise and I'm really not sure whether it's the brakes, a wheel bearing, or worse. Any ideas? I'm going to take it to a mechanic but wanted to ask here to see if it was something I could do myself. Thanks!

 

The brake pads have noisemakers on them that are designed to make an awful, yet harmless, grinding noise to tell you that the pads are almost worn out. If the noise mostly goes away when you press the brake pedal it is probably that. If the noise gets worse when you press the brake pedal the pads may be fully worn down to the metal, which means you'll need new rotors too.

You can jack up the car and take the wheel off to inspect the pad thickness. Brake pad replacement is not complicated DIY either, it's on the order of changing the oil.