Loud grinding on hard braking

[PAFirefighter81]

hello everyone. The second gremlin I’ve been chasing in the new Ex is the grinding. It only occurs on hard braking and doesn’t do it everytime. Hard braking being defined as quickly slowing from 70mph to 15mph. The rotors and pads were checked. They said everything looked good and the rear pads were actually new. Trying to find the gremlin that is causing the noise only during hard brake (no sound during normal braking on my drive to work, 38 mins with several stop signs during the trip)

 

[peterk9]

Wheel bearings??

Peter

 

[Jacob Thomas]

Hello. This may sound dumb but are you sure it isn't your Anti Lock Brake system working like it should? It will be very loud and you should feel it in the pedal as well. A good way to test it is to get your tires very wet ( a garden hose works well) then go 30mph or so and floor your brake pedal as hard as you can and it will be exactly what you are describing Or you can wait untill it rains where you are if you can't get it to work for you . Hope this helps some

 

[PAFirefighter81]

Wheel bearings??

Peter

Was thinking the same thing. Having the wheel bearings checked and the CV to make sure everything is good

Hello. This may sound dumb but are you sure it isn't your Anti Lock Brake system working like it should? It will be very loud and you should feel it in the pedal as well. A good way to test it is to get your tires very wet ( a garden hose works well) then go 30mph or so and floor your brake pedal as hard as you can and it will be exactly what you are describing Or you can wait untill it rains where you are if you can't get it to work for you . Hope this helps some

Not dumb, the mech asked me the same. Maybe I’m not use to the ABS in this one. My truck pulsates like railroad tracks. The mech said he’ll do a ride along with me

 

[KayGee]

Hello. This may sound dumb but are you sure it isn't your Anti Lock Brake system working like it should?

Stranger things have probably happened, but I hope this isn't what it is...

Do you have any history on the vehicle? Is the grinding from the front/rear/both? You may want to re-check the brakes (if the same mechanic that did your 'tune-up' also checked the brakes), then wheel bearings, then driveline.

 

[aypanthony]

Another uncommon/strange thing to consider. I have a 2013 Ex that had a grinding sound on braking. As it turns out, the front rotor had a rust hole. The hole was on the inner side of the rotor, so it was hard to see. Make sure you look and or feel both sides of the rotor.

 

[PAFirefighter81]

Stranger things have probably happened, but I hope this isn't what it is...

Do you have any history on the vehicle? Is the grinding from the front/rear/both? You may want to re-check the brakes (if the same mechanic that did your 'tune-up' also checked the brakes), then wheel bearings, then driveline.

No history. Grinding only in the front when braking hard (like someone cut you off)

Another uncommon/strange thing to consider. I have a 2013 Ex that had a grinding sound on braking. As it turns out, the front rotor had a rust hole. The hole was on the inner side of the rotor, so it was hard to see. Make sure you look and or feel both sides of the rotor.

View attachment 163047

Did you hear grinding during all braking or only hard stops?

 

[aypanthony]

No history. Grinding only in the front when braking hard (like someone cut you off)



Did you hear grinding during all braking or only hard stops?

You could hear the bad grinding during hard stops or multiple consecutive stops. During regular driving, it wasn't really apparent.

It was frustrating at first because the pads had plenty left, but I never had considered a hole in the rotor. I finally just decided to do a full brake job with new rotors and pads and that's when I saw the hole in the rotor. Surprised as hell, since I have never seen that before.

 

[KayGee]

You could hear the bad grinding during hard stops or multiple consecutive stops. During regular driving, it wasn't really apparent.

It was frustrating at first because the pads had plenty left, but I never had considered a hole in the rotor. I finally just decided to do a full brake job with new rotors and pads and that's when I saw the hole in the rotor. Surprised as hell, since I have never seen that before.

I've seen some pretty surprising stuff when doing brake jobs, but can't say that I've seen a hole like that. The strangest stuff I've seen has been pads worn completely through to the point the caliper piston was contacting the rotor - pad shims that slid down and cut through the rotor hat - rotors worn through to the vanes on one side.

You should post it to r/justrolledintotheshop