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Slight thumping noise when braking at highway speeds


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rejesterd
User

Dec 4, 2017, 7:21 AM

Post #1 of 6 (618 views)
Slight thumping noise when braking at highway speeds Sign In

I have a 2016 Kia Sorento LX 3.3L V6 with 49k miles on it. I feel a slight vibration when braking at a highway speeds (above 60mph). The intensity of the vibration is low and doesn't shake the steering wheel. But I can feel it through my feet and hear it. I would categorize it as a low-pitched thumping noise as opposed to a grinding/squeaking noise. The intensity actually dropped off after the last time I rotated my tires (which was about 4k miles ago), but it's still there. For reference, I've been very consistent in rotating the tires every 5k. I also checked all my pads and rotors and they're all well within spec. Very little wear on the rotors, and the pads are all wearing evenly (and by that, I mean they're wearing parallel to the rotors and evenly between driver and passenger side).

In addition, sometimes when I'm on a smooth stretch of highway, I can hear a similar low-pitched thumping noise even when I'm not braking. It seems like the noise comes from the rear, so I put the car up on jack stands and manually rotated the wheels by hand. I hear a slight scraping noise on the rear passenger-side wheel when I do that. Now the noise doesn't happen the entire time that I spin the wheel.. it happens once per full rotation. It's quick scrape/grind, then it's gone until the wheel rotates back to the same point.

How would you go about troubleshooting this? Thanks.


Discretesignals
Ultimate Carjunky / Moderator
Discretesignals profile image

Dec 4, 2017, 7:56 AM

Post #2 of 6 (605 views)
Re: Slight thumping noise when braking at highway speeds Sign In

That vehicle still should be covered under manufacturer's warranty. Has the dealer checked it out?





Since we volunteer our time and knowledge, we ask for you to please follow up when a problem is resolved.


rejesterd
User

Dec 4, 2017, 8:25 AM

Post #3 of 6 (597 views)
Re: Slight thumping noise when braking at highway speeds Sign In

I took it to the dealer, and they said they didn't hear the noise or feel a vibration. I could take it to another dealer I suppose, but I would like to know what the possible causes are (just for my own knowledge).


Tom Greenleaf
Ultimate Carjunky / Moderator
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Dec 4, 2017, 9:35 AM

Post #4 of 6 (582 views)
Re: Slight thumping noise when braking at highway speeds Sign In

Dang. If it didn't do it in person with the dealer it's going to take more looking. Since it does this with braking at least mostly it's a brake or tire issue despite rotating tires and so you think checking brakes it's still probably one or the other is the cause. It could get better or change you said with rotating tires is a clue might be misleading you if it's not the same all the time anyway?


What can do this at 49K but looks (guessing you rotate your own tires) like brakes WEAR is good may have to take those apart to re-lube them and check rotors clearly for a problem by looks with calipers off AND spin checking for "run-out" which is for warpage. Doesn't take much.


Causes?? Assorted including just 49K miles brakes highly dependent on exposure and type of use. Yes - even within 2 years can wash out grease or be worn out but what you see with wheels off look good? All items that get lubed should be while there and good for it anyway.
If easy take rotors off and inspect for debris or corrosion unseen where they mate with hubs. Clean those off with a gasket scraper as needed and rust proof slightest smear of brake lube grease has always worked for me.


Tires: Same they have some miles on them despite maybe rated (which is for comparison not actual miles) more and be legal may be ready to do all. If one was fixed the steel would corrode inside and tread separates or does just anyway sometimes. Hard to see and check that if not obvious.
Some vehicles gun rust rotor just overnight if wet or damp out or condensation slowly become unevenly true - and aren't.
ASK for warranty on brakes a wear item is iffy to me under warranty at about life expectancy anyway. Tires usually covered by the maker of the specific tire but at 49K's worth of wear if only one you really should want all 4 and doubt that would happen without a recall on the specific ones.


Should be one or both of those things unless unknown junk got on brakes or harmed a tire. IDK - it's possible to have hit or other reason some grease or an oil got on rotors + pads they would show a color on one or an area different than the others.


Can take time when things don't misbehave for something not obvious to pin it down just don't give up,


T



rejesterd
User

Dec 4, 2017, 12:37 PM

Post #5 of 6 (571 views)
Re: Slight thumping noise when braking at highway speeds Sign In

Thanks. I did check for runout in the rotors (at different spots) with a dial indicator, but they all seemed ok. However, I didn't remove the rotors and fully inspect them. I only did the runout test and measured the thickness with a micrometer. Couldn't hurt to just take them off, clean them up, and remount them.

I'm actually getting new winter tires put on this weekend, so I'll inspect the rotors more closely if the issue still remains with the new tires.


Tom Greenleaf
Ultimate Carjunky / Moderator
Tom Greenleaf profile image

Dec 4, 2017, 4:12 PM

Post #6 of 6 (567 views)
Re: Slight thumping noise when braking at highway speeds Sign In

OK, if you swap all wheels and tires for Winter time to take all off at once vehicle hoisted and do some serious looking for a flaw. Take the calipers off with pads in them and spin the wheels you can probably see the problem. Check the dust shields aren't bent too. Lube things up with "brake grease" and see if any oil of something has gotten on anything.


Tires if you are swapping whole wheels and tires and this still can do this that rules out those so it's down to brake issue. Hot spots on friction surfaces should be visible but you can't see the pad to rotor area of pads with them on, that's all and should look,


T







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