Brake Judder - feels like I’ve tried everything

[YR20]

Hi All,

I have owned my Stinger GT 2020 for 6 months (52k miles).

I am in the UK (NE England)

The car has always juddered under braking since I’ve owned it, and I just can’t seem to track down the issue, it’s been driving me crazy.


I’ve had it in to 2 KIA dealers, who were useless, but still made sure to charge me diagnostic fees for not finding anything.


So far, I have tried:

• ⁠4 Wheel alignment
• ⁠Wheel balancing
• ⁠Replaced all discs and pads, with EBC Slotted Discs and Yellow Stuff Pads
• ⁠Had the Calipers inspected
• ⁠Had multiple health checks carried out
• ⁠New tyres all round (Michelin Pilot Sport 4s)


The tie rod ends seem okay, not much movement in them. The juddering happens ONLY under braking.


Nothing has worked, and I’m now multiple thousands into the hole on trying to get this car braking correctly.

Does anyone have any advice on what else I can try?

I’m considering putting it on a rolling road.

 

[Thomby]

The usual answer here is deposits from the soft OEM brake pads onto the brake rotors, but you appear to have aftermarket rotors and pads. Did anything change when you first replaced the rotors?

A couple troubleshooting steps you can try:
- A handful of hard braking sessions (say from 50-70mph down to a near stop) to get some heat into the pads & rotors, and try to scrape any deposits clean. Ideally you would cruise around for a while after this without stopping, to avoid having the pads against the rotors while things cool down
- Pitching the car into sweeping curves while braking, to get more weight on each side and see if there's a noticeable difference (I've used this to confirm a bad wheel bearing)
- Put the car into neutral while cruising and then brake, to confirm it's nothing in the driveline
- Leave the car in gear while cruising, and downshift with the shifter paddles to "brake" without using the brakes

 

[YR20]

The usual answer here is deposits from the soft OEM brake pads onto the brake rotors, but you appear to have aftermarket rotors and pads. Did anything change when you first replaced the rotors?

A couple troubleshooting steps you can try:
- A handful of hard braking sessions (say from 50-70mph down to a near stop) to get some heat into the pads & rotors, and try to scrape any deposits clean. Ideally you would cruise around for a while after this without stopping, to avoid having the pads against the rotors while things cool down
- Pitching the car into sweeping curves while braking, to get more weight on each side and see if there's a noticeable difference (I've used this to confirm a bad wheel bearing)
- Put the car into neutral while cruising and then brake, to confirm it's nothing in the driveline
- Leave the car in gear while cruising, and downshift with the shifter paddles to "brake" without using the brakes

Thanks, Thomby.

I noticed no improvement in the judder when I replaced all the brakes, if anything it feels more aggressive? (Enough to physically shake the steering wheel)

I can give a few of your suggestions a try tonight, I have heard from a few Stinger owners that their cars also have the same issue, but they have just lived with it. Not something I could live with, personally

 

[Thomby]

I would suggest something like a bent wheel, but that should make the vibration constant. Any chance it's there but subtle, and becomes more noticeable when you put weight on the front under braking? Or the opposite: if you just drag the brakes so there's little forward weight shift, is it still just as bad?

If you didn't go through the bedding process when you swapped your brakes, that may be worth a try. Different manufacturers have different specifics, but it's usually some combination of several light, medium, and hard braking applications to get everything hot and then transfer brake material to the rotors evenly (with a cool down cruise afterwards so you aren't holding hot brake pads against hot rotors in one position).

 

[YR20]

I would suggest something like a bent wheel, but that should make the vibration constant. Any chance it's there but subtle, and becomes more noticeable when you put weight on the front under braking? Or the opposite: if you just drag the brakes so there's little forward weight shift, is it still just as bad?

If you didn't go through the bedding process when you swapped your brakes, that may be worth a try. Different manufacturers have different specifics, but it's usually some combination of several light, medium, and hard braking applications to get everything hot and then transfer brake material to the rotors evenly (with a cool down cruise afterwards so you aren't holding hot brake pads against hot rotors in one position).

What confuses me is that the juddering was present with the original KIA brakes.

I don’t feel vibration when accelerating or cruising/travelling, only under braking. Both low speed and high speed braking causes the issue; I was convinced it was the braking system, but it could be something in the drivetrain?

I’ll give those troubleshooting ideas a try tonight, I’m hoping it’s something I can finally get to the bottom of, I’ve been ripping my hair (and wallet) out trying to get my car to just brake correctly.

 

[Ah GetFd]

Replace all the rubber bushes around the front suspension.

You might also look at the front struts and see if they have any movement