#Car shaking while braking at high speeds > Audi A5 -23

29 messages · Page 1 of 1 (latest)

daring fjord
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Hi,

I slapped on my summer tires, and noted that the car shakes when braking at high speeds. I went and got the wheels balanced and the front brake discs lathed down 0.1mm, but that kind of made the problem worse...

I think I've narrowed it down to something being off about the front left tire/brake, as when I turned right on an on-ramp and applied the brake, the front left made a sort of "clucking sound". That transformed into the front left making intermittent squeaks, even while not braking. I can also feel slight vibrations that get worse with speed.

Any ideas as to what I should look at?

digital kettleBOT
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buoyant drift
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Wheel bearing?

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If you haven’t checked that I suggest you do, easy to do.
There are yt videos that save me having to explain how 👍

digital kettleBOT
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GG @buoyant drift, you just advanced to level 3! Chat more to level up and earn top roles!

daring fjord
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Hmm.. searched around a bit, and one of the symptoms was that the tire pressure monitor warning may kick in, which it did while I was testing the brakes on the highway.

shadow musk
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Honestly shounds like the wheel is falling off. Are the lugnuts torqued to spec?

daring fjord
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Could be a bit over-spec even, but that would apply to all tires in that case, the problem only seems to be with the front left tho

shadow musk
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A wheel bearing does not go bad from simply changing the tire.

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Is the tire round lol?

daring fjord
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Yes 😄

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No flat spots or anything

buoyant drift
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And it’s an easy check

shadow musk
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Could be stuck slidepins and the brake turning was not done correctly.

daring fjord
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Could the stuck slidepins cause cyclical squeaky noise and vibrations, even while not braking?

shadow musk
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yes

daring fjord
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Might be worth investigating that angle in that case

shadow musk
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Especially when turning because there is a bit of deflecton in the wheel bearing

daring fjord
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Hmm.. I'll have to check it out tomorrow, shitty ass timing since I'm going on a 1.5k mile roadtrip tomorrow.. 😅

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Thanks for the suggestions, I'll be sure to check the wheel bearing as well

lost elk
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My money is wheel bearing as well, but it’s worth taking off the caliper and removing the pins, relubing them, reinstalling them. When you are able.

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Also another worthwhile check is swapping the two front wheels and see if the problem stays on driver side or goes to passenger side

daring fjord
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Some additional information that I forgot to mention, when keeping the same brake pressure at low speeds, it tends to cyclically brake "harder", really noticeable and annoying when approaching stoplights.

lost elk
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That really sounds like warped rotors, which can be related and made worse by a failed/failing wheel bearing

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I see you had them turned, was runout checked with the rotors on the car?

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What I’m getting at is, a wheel bearing may not rotate on a flat plane, creating the effect of a warped rotor; so the same rotor may show no runout on a machine, but then installed on the car it will act as if it is warped.

daring fjord
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Hmm, it was not checked while on the car, will have to try checking it on tomorrow as well