Knocking when going over bumps

[jyi786]

2019 Cadillac Escalade ESV. Bought at 24K miles, at that time, had replaced all sway bar bushings. At 104K miles now.

When coasting over bumps/rough road, I'm hearing a loud knocking/clattering coming from the bottom left of the vehicle (I think). Can hear it easily with the driver side window down. As soon as I apply the brakes, the noise goes away.

I've already checked the caliper, brake pads, made sure all suspension components are tight and nothing is loose. Does it sound like the sway bar bushings need to be changed? Want to be sure before I throw the parts cannon at it.

Thanks!

 

[B-train]

Does the noise go away with light brake pressure? If not, then I'd look at sway bar links

 

[jyi786]

Does the noise go away with light brake pressure? If not, then I'd look at sway bar links

Matter of fact, yes. I tested it by accelerating and just ever so lightly touching the brake pedal, so in effect accelerating and braking at the same time, and when doing so, the rattling/clattering sound disappears. The second I remove my foot from the brake, it clatters.

 

[B-train]

Then you have worn anti-rattle clips on the caliper that holds the pad most likely. I had a similar issue on my 2500HD where I would hear a rattle echo off buildings or walls at slow speeds. I narrowed it down like you did and put nww brake pads and hardware on.

Depending on your driving habits, you may be due for new brakes anyways.

 

[jyi786]

Then you have worn anti-rattle clips on the caliper that holds the pad most likely. I had a similar issue on my 2500HD where I would hear a rattle echo off buildings or walls at slow speeds. I narrowed it down like you did and put nww brake pads and hardware on.

Depending on your driving habits, you may be due for new brakes anyways.

I can assure you it's not this, because like you, I thought it was either the anti-rattle clips or maybe even really bad pad-slap.

The calipers, anti-rattle clips, and pads are brand new. I went back in yesterday, tore the brakes apart, and ensured that everything was in their proper place, lubed up properly, and torqued down to spec. Not using junk hardware either: all GM OEM stuff, and the brake pads are Akebono premiums. Still has 95%+ life on the pads.

 

[B-train]

Hmm....did you use high temp silicone on the back of the pads where they mate the caliper by chance? I always put a thin coat just to make sure they don't get sticky against the metal.

I guess the other thought would be a loose suspension component (ball joint, tie rod) that may change geometry when the brakes are applied and make the joint tight again?

 

[jyi786]

Hmm....did you use high temp silicone on the back of the pads where they mate the caliper by chance? I always put a thin coat just to make sure they don't get sticky against the metal.

I guess the other thought would be a loose suspension component (ball joint, tie rod) that may change geometry when the brakes are applied and make the joint tight again?

Yep, absolutely. I do that religiously because one thing I hate is brake noise.

Loose suspension component sounds like a definite culprit. I went ahead and got new sway bar bushings and sway bar link kit. They will be here tomorrow.

 

[jyi786]

Update: changed all sway bar bushings and the sway bar links up front. No change in noise. Took to stealership, tried to let them diagnose. They heard it, but couldn't find it because they didn't have time and scheduled me for next Tuesday.

I'm going to point them to either motor mount (because it seems like it's still an issue this gen), and UCA bushings.

Edit: matter of fact, come to think of it, I'm almost 99% sure it's the motor mount. I now recall that I had this exact issue with my 2012 Yukon Denali XL that was remedied when I had a local shop replace the motor mount with the Hummer H3 mount.

 

[duke90]

I have a very similar noise on my '17 and I know my driver's side motor mount is busted. I ordered a pair of mounts from atomic fab and will install them once they come in. Hopefully that solves the problem.

 

[Dearmosd]

check the emergency brake cable. I had a similar sound, I tried to secure the cable better and it helped for a bit but found its way back. I can mimic the sound when tugging on my emergency cable pathway.