CT4-V Intermittent Front (?) Suspension Noise

[BWDudeBro]

I will gather more detail as I continue to hear this, but wondering if anyone else is experiencing similar issues.

My 4BW has ~3700mi and I'm getting a pronounced "extra" noise as the front suspension cycles over sharp impacts. It's tough to reproduce, so I can't yet tell if it's isolated to one side or only on compression and rebound. It almost sounds like sway-bar bushings when they get really old... a thwacky-clunk over impacts that doesn't last very long.

I had the car in the air a few weeks back to install jack pads and swap brake pads. I don't recall any noises prior to that. I've swapped pads 100 times on previous cars for track duty, so I feel confident that I didn't introduce any issues there. I've double-checked wheel torque. I'm struggling to see how adding jack pads would have intro'd a noise like this, which leads me to wonder if the timing is coincidental.

Anyone else getting noise over sharp bumps?

 

[hrdboiled]

4bw 24,000 miles. I developed a noise like something is loose under the dash. It seems to be suspension related and is very subtle. Bugs the crap out of me. Not all the time but mostly going over rough roads. happens more when going 30-45 mph and wheel slightly right. Suspension feels slightly harsher than when new. Anyway, jacked up the car and driver strut has a resevoir or something that is covered in fluid. Dont know if that's the cause, but going to get it checked out.

 

[jbawden]

I was going to say brake pads before I even read that you replaced them. My troubling shooting always goes back to the last thing I did, so I can almost guarantee it’s the pads. These Brembo calipers are known to have this issue, particularly with non-oem pads that don’t fit as well or without as well engineered tension springs.

 

[BWDudeBro]

I was going to say brake pads before I even read that you replaced them. My troubling shooting always goes back to the last thing I did, so I can almost guarantee it’s the pads. These Brembo calipers are known to have this issue, particularly with non-oem pads that don’t fit as well or without as well engineered tension springs.

Yep, good call... I initially suspected this since my truck has this bad, but thought for sure these calipers wouldn't have an issue since my Mustang Brembos never did.

After posting this, I drove the car 400 miles this weekend, and noticed a pronounced *click* about half the time I applied the brakes. That led me back to this issue - if the pads are shorter in overall length than OEM, they'll click as they grab the rotor - the click noise is their edges bumping against the inner surfaces of the caliper.

I did some googling and someone suggested that if a rotor is warped (which I know my truck's are), then the "wide" part of the rotor's runout would push the pads back away from the friction surface, meaning they're then again loose to rattle.

To troubleshoot this correctly I need to find some bumps = to recreate it consistently so I can go over them with and without brakes applied. If that fixes it, measuring the overall length of the Powerstop pads vs. OEM will prove it.

 

[BWDudeBro]

4bw 24,000 miles. I developed a noise like something is loose under the dash. It seems to be suspension related and is very subtle. Bugs the crap out of me. Not all the time but mostly going over rough roads. happens more when going 30-45 mph and wheel slightly right. Suspension feels slightly harsher than when new. Anyway, jacked up the car and driver strut has a resevoir or something that is covered in fluid. Dont know if that's the cause, but going to get it checked out.

Interesting. That definitely describes my issue, but after this weekend I'm inclined to try the brake pads first (see above).

But yeah, that's just the bottom of your mag ride damper. Can you see an active leak? If not it's hard to tell if that's coming from the damper itself or perhaps something you kicked up.

 

[DCV]

I had a rear shock that did the same thing. Subtle at first then it got worse and I took it to the dealer, and the left rear shock was bad. It’s not supposed to be wet there. Take it in. Mine went bad when the GM strike was hitting, so no parts were shipped till that ended. But they got one in and it’s all fine now.

 

[BWDudeBro]

For those playing along at home, I'm now 95% sure my noise is due to my front Powerstop pads being cut too short. Without the brakes applied, small, sharp bumps between 20-40mph will cause the pads to move vertically inside the calipers. The noise is likely the pad top and bottom edges rather than the backing plate or friction surface.

I'll be able to verify once I have time to get the car in the air, but this all makes too much sense.

As far as a fix, I don't really want to go back to stock if I can help it. The dust was INSANE... I love the feel of the Powerstops and they have essentially zero dust.

I may reach out to Powerstop in the meantime to see if they have anything to offer.

 

[BWDudeBro]

Coming back with a rare "I think I've got this one figured out" update. Hope this helps someone in the future.

My thought from July was correct - The Powerstop pads rattling in calipers over bumps.

I removed each front pads and applied an even coat of CRC Disc Brake Quiet across the entire backing plate. I then applied a thin bead along each top and bottom edge. Finally, I "filled" the holes in the pads where the caliper pins go through.

This stuff dries into an almost-rubber consistency (a bit like RTV, but presumably more tolerant of higher temps). I gave the pads probably 20-30min to dry, at which point they could be reinstalled without disrupting the now-rubbery CRC.

I'm happy to report that this did the trick. I'd say the noise is 98% better. If there's any remaining noise, it's hard to say it isn't just everything else you'd hear over a sharp impact (suspension interior noise, tire thud, etc).

 

[LCSA]

I will gather more detail as I continue to hear this, but wondering if anyone else is experiencing similar issues.

My 4BW has ~3700mi and I'm getting a pronounced "extra" noise as the front suspension cycles over sharp impacts. It's tough to reproduce, so I can't yet tell if it's isolated to one side or only on compression and rebound. It almost sounds like sway-bar bushings when they get really old... a thwacky-clunk over impacts that doesn't last very long.

I had the car in the air a few weeks back to install jack pads and swap brake pads. I don't recall any noises prior to that. I've swapped pads 100 times on previous cars for track duty, so I feel confident that I didn't introduce any issues there. I've double-checked wheel torque. I'm struggling to see how adding jack pads would have intro'd a noise like this, which leads me to wonder if the timing is coincidental.

Anyone else getting noise over sharp bumps?

My ‘24 4BW has a noise exactly as you describe here. It has 1,000 miles on it, but has been doing it since the day it was new. Almost sounds like it’s “cycling” as it goes over bumps at medium to low speeds. I describe is exactly as you did - if it were an old car would say it needs suspension bushings! Car is fully stock.

 

[BWDudeBro]

My ‘24 4BW has a noise exactly as you describe here. It has 1,000 miles on it, but has been doing it since the day it was new. Almost sounds like it’s “cycling” as it goes over bumps at medium to low speeds. I describe is exactly as you did - if it were an old car would say it needs suspension bushings! Car is fully stock.

Does it seem to be isolated more in the front or the rear?

 

[LCSA]

I will gather more detail as I continue to hear this, but wondering if anyone else is experiencing similar issues.

My 4BW has ~3700mi and I'm getting a pronounced "extra" noise as the front suspension cycles over sharp impacts. It's tough to reproduce, so I can't yet tell if it's isolated to one side or only on compression and rebound. It almost sounds like sway-bar bushings when they get really old... a thwacky-clunk over impacts that doesn't last very long.

I had the car in the air a few weeks back to install jack pads and swap brake pads. I don't recall any noises prior to that. I've swapped pads 100 times on previous cars for track duty, so I feel confident that I didn't introduce any issues there. I've double-checked wheel torque. I'm struggling to see how adding jack pads would have intro'd a noise like this, which leads me to wonder if the timing is coincidental.

Anyone else getting noise over sharp bumps?

Does it seem to be isolated more in the front or the rear?

The clunking with “cycling” is in the front. There is a different clunk in the rear. A new shock on the left rear cured that. Right rear has a very light clunk, waiting for that to get worse before I take it back in. Not sure what to think of the front. As I said, started basically immediately when the car was new. Only over specific bumps, normally worse when turning. The other thing I thought of was the electric power steering, but I can’t really think of a reason that would create this particular noise.

 

[hrdboiled]

The clunking with “cycling” is in the front. There is a different clunk in the rear. A new shock on the left rear cured that. Right rear has a very light clunk, waiting for that to get worse before I take it back in. Not sure what to think of the front. As I said, started basically immediately when the car was new. Only over specific bumps, normally worse when turning. The other thing I thought of was the electric power steering, but I can’t really think of a reason that would create this particular noise.

pull the wheel off and check the strut reservoir. Mine felt like intermittent rattle/clunk was coming through the steering column. Would only happen when turning slightly right. I pulled the wheel off and the strut reservoir was covered in some sort of fluid. Dealer replaced strut and I love my car again. Here's a video of what it sounded like. It was annoying. PXL_20240805_195038095.mp4

 

[gusandcars]

Seems like you've already tracked down the issue, but FWIW, my 4BW left the factory with a defective passenger front strut. Ride quality was not compromised but there was clunking on every sharp up-travel regardless of drive mode. Rough pavement would produce typical blown shock clunking noises and speed bumps would produce a "thunk," always timed with front suspension travel. Went in for warranty replacement within the first couple weeks, they replaced the strut, and I've had zero noise or issues since.