Pulsing brakes at highway speeds

Discussion of Infiniti's amazing (and underrated) sport-luxury crossovers, the EX35 and EX37. For 2014, the EX series will be renamed QX50, in line with Ininfiit's new naming conventions.
TrevEB
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Pulsing brakes at highway speeds

Postby TrevEB » Mon Jul 18, 2022 7:41 am

This topic has been touched upon in the past. Just want to followup on the correct diagnosis.
We feel a pulsing sensation when applying the brakes, most noticeable at highway speeds.
It feels like grip/release/grip/release.
As if the brake pads are rolling over a bump on the rotars causing the pulsation.
I cannot determine which of the 4 brakes the pulse is coming from.
It’s been growing stronger over the last couple years. No one believed me when I first noticed it. Car shops, tires replaced, and the wife all said they could not feel it.
Well, now the wife feels it. :)

So, yes mostly likely warped rotors?
Was there any quiet recall for this issue years ago?
I thought I had come across the topic earlier and that I was to late to the party.


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AZhitman
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Re: Pulsing brakes at highway speeds

Postby AZhitman » Mon Jul 18, 2022 7:59 am

"Warped" rotors is typically the first thing people think of. However, it's a big deal to "warp" a rotor.

More often than not, it's a transfer of material from the pads to the rotor face from sitting, driving through a big puddle with hot brakes, or... well, disuse.

Start with a good visual inspection. Rotor surface should be clean, glossy, with faint concentric lines around the face. If you see any anomalies, inspect closer. I have in the past pulled the wheels and run the car in drive on a lift to inspect for rotor runout.

If all else fails, perform a "brake bedding" procedure (Google) such as what you'd do when installing new brake shoes. If that doesn't square it up, new rotors are inexpensive.


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