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Flat Tire Noise When Braking Downhill

by mickemoose, June 16, 2011



This one stumps me. The front brake(s) on my '05 Corolla LE make a flat tire noise ONLY when I brake going down a steep hill. Sounds like a "wup-wup-wup-wup" noise when brakes are applied. No feedback (pulsation) in the brake pedal which makes this issue even more confusing. If it did, I would suspect a warped rotor. However, when I brake on a flat road surface, I don't hear the noise.

Have plenty of stopping ability. The Toyota dealership inspected the brakes on 3-31-11 and said I have 70% brake left. Mileage at that time was 70,372.

Current mileage of vehicle is 72,232. Seems a bit premature to have a CV joint go south this early.

This is the first real issue I've had with this '05 since I bought it new in October '04. That's a pretty decent track record, I would think!

Any help is greatly appreciated!

Need a bit more info:

Does the noise follow vehicle speed?

Faster you are traveling downhill, the faster the "wup-wup" frequency?

Have you tried rotating the tires and see if the noise follows the tires or stays put?

Which tires are on the car, are they the original ones, or did you have them replaced recently?

Happening when braking downhill is pretty specific - though could still be several things causing that. Brake system will be on my short list to check out. Pads could be fine, I'd check the rotors and make sure the calipers and torque plate are not loose. Rotors that get very hot can make a flat-tire like noise, they generally don't cause any braking issue or pedal pulsation, at least initially. An issue with the tire is very possible. Could be a slipped belt, broken belt inside the tire - that should be very evident when you rotate the tires. Rotating the tires will also move the wheels, so this can also check for bent wheels as well. Might be worthwhile to jack up each corner of the car and spin the wheels by hand - noting anything unusual, like lumps, bumps, funny wavy tire surface, and obvious signs of damage/wear.

If brakes, tires, and wheels check out - could be alignment, steering or suspension related. As you are braking downhill, tires will slightly toe-out and suspension/steering components will shift under the weight transfer. Since you are going downhill, this amplifies the affect. Pretty common on smaller cars, as their braking systems are cheaper/undersized and suspension is not as beefy as your sport oriented cars are.

Thanks, Fish!

The original Goodyear Integrity tires were replaced with 4 new Michelin Harmonys on 10-26-09 at 55,010 miles.

Since new tires were put on, they have been rotated twice - the first rotation on 3-22-10 at 60,180 miles, and the latest rotation on 3-31-11 at 70,372 miles.

The noise appears when I brake when traveling down a steep grade.

Yesterday afternoon, I brought my sister's dog to the veterinarian's office which is located halfway down a steep hill. I was only going down about 30 mph down the hill when the noise appeared, each time I applied the brakes. It continued even as I turned in to the vet office parking lot, but it was slowing in frequency in relation to the slowing vehicle speed. The noise went from a fast "wup-wup-wup" traveling down the hill to a slow "wup----wup----wup" as I turned in to the parking lot.

Those Michelin tires are known to be pretty quiet, so that shouldn't be the issue. The noise related to ground speed definitely sounds like it is brake related. Sometimes, when pads just start to overheat - like braking downhill, they will harden and their friction properties will change slightly. That could have scrubbed off the brake transfer layer that coats surface of the rotor and pads. If scrubbed off unevenly, it would cause that funny noise during braking. But should also do it when you brake briskly on level ground. Braking downhill aspect makes it sound like a suspension/alignment issue. Possible, you have a combination issue.

If it is possible to grab a sound clip of the noise, that would be great.

Well, this morning I did my own testing, and the noise is a strange one indeed. I drove the car on rural paved roads with hardly any traffic and I made the following observations:

- No noise is evident under acceleration.

- Upon releasing the gas pedal and coasting, a slight, yet noticeable percolating sound (similar to a coffee pot) appears at about 35 mph.

- After accelerating up a gradual hill and slowly making a right turn, the "wup-wup-wup" noise began to sound. Then, as I coasted down the following adjacent grade, the noise mellowed to the slight percolating sound nearly all the way to the stop sign at the bottom of the hill.

- I firmly applied the brakes several times - on straight stretches, around curves, etc. No noise at all, and the brakes have plenty of stopping power.

- Went back on the highway again and sped up to 55 mph. Again, no noise under acceleration.

From what I observed today, the noise doesn't seem to be brake-related.

There's two reputable auto repair facilities in my area, one of them put on my Michelins, so I'll probably bring it there and have them check it out.

ever_green

what pressure are you running in these tires? have you inspected them for damage? might have a sidewall bubble?

Since the braking doesn't seem to the source - possible there is a tire issue. As mentioned by ever_green - could be a sidewall bubble from a broken side belt, flat spot, excessive belt lap, etc. Incorrect tire installation could also cause the noise issue - same with incorrect wheel installation (too much or too little lug torque, wheel not centered onto hub).

This one stumps me. The front brake(s) on my '05 Corolla LE make a flat tire noise ONLY when I brake going down a steep hill. Sounds like a "wup-wup-wup-wup" noise when brakes are applied. No feedback (pulsation) in the brake pedal which makes this issue even more confusing. If it did, I would suspect a warped rotor. However, when I brake on a flat road surface, I don't hear the noise.

Have plenty of stopping ability. The Toyota dealership inspected the brakes on 3-31-11 and said I have 70% brake left. Mileage at that time was 70,372.

Current mileage of vehicle is 72,232. Seems a bit premature to have a CV joint go south this early.

This is the first real issue I've had with this '05 since I bought it new in October '04. That's a pretty decent track record, I would think!

Any help is greatly appreciated!

Have a Corolla with similar mileage. Went to an Angie's list auto shop and got an alignment. Had no noise whatsoever when braking when entered this establishment...but after leaving the establishment heard a weird wup-wup rubbing noise from the back upon braking at the red lights. Called back the shop and asked what it could be. They said to bring it back...which I did. They said they "drove it hard" and did not hear a thing! Within the week, went to another shop and found that the drums and shoes on both sides had to be replaced. They tried to machine them to smooth out the warpage...but it was too messed up! As an addendum, the drums and shoes had been replaced only a little over a year ago.and were practically new! So...what my credit card and I have learned is this...It there are weird sounds and the mechanics that screwed it up will not be honest and say they did it...it only ruins more and more car parts the longer that you drive it. By the way, with the new shoes and drums, the car is quiet as a mouse as it was before going to that hateful place. I learned that what can cause this warpage to happen is if the tire is put on too tightly or too loosely...it will with the rotation of the tire and the accompanying heat, cause the warpage.

 

 

 

This one stumps me. The front brake(s) on my '05 Corolla LE make a flat tire noise ONLY when I brake going down a steep hill. Sounds like a "wup-wup-wup-wup" noise when brakes are applied. No feedback (pulsation) in the brake pedal which makes this issue even more confusing. If it did, I would suspect a warped rotor. However, when I brake on a flat road surface, I don't hear the noise.

Have plenty of stopping ability. The Toyota dealership inspected the brakes on 3-31-11 and said I have 70% brake left. Mileage at that time was 70,372.

Current mileage of vehicle is 72,232. Seems a bit premature to have a CV joint go south this early.

This is the first real issue I've had with this '05 since I bought it new in October '04. That's a pretty decent track record, I would think!

Any help is greatly appreciated!

Have a Corolla with similar mileage. Went to an Angie's list auto shop and got an alignment. Had no noise whatsoever when braking when entered this establishment...but after leaving the establishment heard a weird wup-wup rubbing noise from the back upon braking at the red lights. Called back the shop and asked what it could be. They said to bring it back...which I did. They said they "drove it hard" and did not hear a thing! Within the week, went to another shop and found that the drums and shoes on both sides had to be replaced. They tried to machine them to smooth out the warpage...but it was too messed up! As an addendum, the drums and shoes had been replaced only a little over a year ago.and were practically new! So...what my credit card and I have learned is this...It there are weird sounds and the mechanics that screwed it up will not be honest and say they did it...it only ruins more and more car parts the longer that you drive it. By the way, with the new shoes and drums, the car is quiet as a mouse as it was before going to that hateful place. I learned that what can cause this warpage to happen is if the tire is put on too tightly or too loosely...it will with the rotation of the tire and the accompanying heat, cause the warpage.

 

This one stumps me. The front brake(s) on my '05 Corolla LE make a flat tire noise ONLY when I brake going down a steep hill. Sounds like a "wup-wup-wup-wup" noise when brakes are applied. No feedback (pulsation) in the brake pedal which makes this issue even more confusing. If it did, I would suspect a warped rotor. However, when I brake on a flat road surface, I don't hear the noise.

Have plenty of stopping ability. The Toyota dealership inspected the brakes on 3-31-11 and said I have 70% brake left. Mileage at that time was 70,372.

Current mileage of vehicle is 72,232. Seems a bit premature to have a CV joint go south this early.

This is the first real issue I've had with this '05 since I bought it new in October '04. That's a pretty decent track record, I would think!

Any help is greatly appreciated!

This one stumps me. The front brake(s) on my '05 Corolla LE make a flat tire noise ONLY when I brake going down a steep hill. Sounds like a "wup-wup-wup-wup" noise when brakes are applied. No feedback (pulsation) in the brake pedal which makes this issue even more confusing. If it did, I would suspect a warped rotor. However, when I brake on a flat road surface, I don't hear the noise.

Have plenty of stopping ability. The Toyota dealership inspected the brakes on 3-31-11 and said I have 70% brake left. Mileage at that time was 70,372.

Current mileage of vehicle is 72,232. Seems a bit premature to have a CV joint go south this early.

This is the first real issue I've had with this '05 since I bought it new in October '04. That's a pretty decent track record, I would think!

Any help is greatly appreciated!

The dealership replaced my front brake pads and I had the same noise upon braking. Went to a local mechanic and they told me that the dealership did not put the clips on the new brake pads. This allowed for decreased stability of the new pads and some movement of the new pads. The rotors were machined and new brake pads were installed with the clips properly put on. The noise is gone when braking on any kind of incline or road conditions now.

 

 



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