2009 Cadillac CTS ... Changed pads, grinding noise now?

jph2275 · 02-20-2013, 08:54 PM

Like the title states

Spent part of today changing out wife's front break pads on her 2009 CTS. I replaced pads only as the rotor looked visually fine and smooth, ran my finger across it. No grooves or grind marks.

After the install I drove 50 miles at speeds of no more than 30 mph and all felt fine. Had to get on highway and breaked at 60 and the steering wheel was shuttering some. It wasn't doing that before I changed pads. After I pulled off I notice a slight grinding noise when I break to a stop. Also a grinding noise when I break while turning right.

I checked again, all pads on right, everything is tight. Wheels put on correctly.

What did I do wrong? Should I have replaced rotors? Will these new pads "break in" after a few miles?

Thanks

Pat

jph2275 · 02-20-2013, 08:57 PM

Grinding noise is not too loud or intense by the way, but somewhat noticeable if you're listening for it

jph2275 · 02-21-2013, 07:23 AM

Bump for advice

djsnoflake · 02-21-2013, 05:32 PM

Did you seat them? (Slow down from highway speed rapidly?) That helps sometimes and then after a few miles it usually dies down as the friction surface gets smoothed out a bit

Russell James · 02-22-2013, 09:30 AM

Sometimes a new pad will be contacting a rusty area on the rotor and take a bit to wear that in.

With it shaking also, here is what I would do. Pop the wheels, calipers, and rotors back off. Sometimes rust and crud falls behind the rotor to hub mating surface. Scrape and clean real good the hub surface, and the rotor surface where it sits flat to the hub. Often there is witness marks or little circles where you can tell to put the rotor back on oriented the the hub in the same way it was originally.

Once you get the rotor back on, caliper... tq the wheels real careful in a star pattern. Then go do about 5 firm stops from a decent speed - 50 ish. Don't overheat the brakes, just moderately firm stops. If there is still an issue, may need the rotors turned.

But if it didn't shake before the pads, I would think the rotors are Ok, and something got a little mucked up in the reinstall. Pretty common for rust to fall back behind the rotor to hub surface and cause a little brake shake. That rotor to hub surface has to be perfectly clean.

02-22-2013, 09:30 AM	#5
Russell James Drives: '15 SS 1LE, '69 Z28 drag car Join Date: Dec 2009 Location: Mich Posts: 4,482	Sometimes a new pad will be contacting a rusty area on the rotor and take a bit to wear that in. With it shaking also, here is what I would do. Pop the wheels, calipers, and rotors back off. Sometimes rust and crud falls behind the rotor to hub mating surface. Scrape and clean real good the hub surface, and the rotor surface where it sits flat to the hub. Often there is witness marks or little circles where you can tell to put the rotor back on oriented the the hub in the same way it was originally. Once you get the rotor back on, caliper... tq the wheels real careful in a star pattern. Then go do about 5 firm stops from a decent speed - 50 ish. Don't overheat the brakes, just moderately firm stops. If there is still an issue, may need the rotors turned. But if it didn't shake before the pads, I would think the rotors are Ok, and something got a little mucked up in the reinstall. Pretty common for rust to fall back behind the rotor to hub surface and cause a little brake shake. That rotor to hub surface has to be perfectly clean.