New front brake pads riding on new rotors and making slight noise - normal?

Question

2009 Scion XD, 110K miles.

I replaced my front rotors and pads with the Raybestos brake kit found on Rock Auto.com. Since I live in the rust belt, and my current rotors rusted apart before the pads burned down, I opted for the coated rotors! Anyway, I'm over 50 and have been doing my own brake jobs since 16 and don't recall the issue of pads riding on my rotors making a slight noise.

I hear it with my windows down, noise bouncing back off the curb or parked cars. It's not pressure, it's not slowing down the car. My car is not pulling when braking. I used silicone to lube the sliders. Used a wire brush to clean the calipers and brush off rust at the contact points where rotor meets the hub assembly and applied anti seize. Used the new clips with the brake kit and the pads came with shims.

It seems the pads are touching the rotors just gliding down the road making that metal noise and it's driving me nuts. Not super loud; I'm just not used to it. I took the brakes apart and I'm not happy and can't find anything wrong! Should I just wait to see if after some pad wear it goes away?

Answer 1

You've mentioned several potential issues in terms of making sure the brake hardware was cleaned and lubed properly, so we can rule those out. In rusty environments it's common for the caliper slide pins to get sticky, causing a brake pad to drag on the rotor, which can make noise (and wear the pad quickly) even if it's not enough drag to actually cause you to feel the car pulling to that side. You said you cleaned and lubed the pins, so we can probably assume that's not the case. Anyways, it's usually obvious when this is happening as the pins will be hard to move by hand and/or you'll see uneven wear in the old pads.

However, it still might be worth a few minutes to take the wheels back off and make sure things look OK. Most cars (including yours) have a thin stamped sheet steel shield behind the brake rotor. It's flimsy and easy to bend - sometimes when it gets bent, it'll touch the edge of the rotor and make a metal-on-metal noise like you're hearing. When you're doing brake work, all it takes is an errant tool smacking that shield or you grabbing it unintentionally while working to bend it enough to cause contact with the rotor. Sometimes it'll wear itself away in a few hundred miles and stop the noise, but it's easy to check and easy to fix (you can straighten the shield by hand in most cases).

And of course, taking the wheel off will let you check that you didn't make any silly mistakes. I once helped a friend diagnose brake noise after he'd replaced his pads, it turned out he hadn't tightened one of the caliper bolts properly and it had backed out to the point that it was rubbing on the inside of the wheel. Luckily we caught it quickly.