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Hey guys, concerning my wife's new 2019 F-Sport. She is complaining about the brake feel and I drove it and under light to moderate braking there is a noticeable pulsating felt in the foot on the brake pedal, almost feels liked warped rotors or a bad bearing that is accentuated by the braking. It isn't felt in the steering wheel. There is no feel under heavy braking. I know Lexus should take care of this if it is an actual issue, considering it only has a few hundred miles, but just wasn't sure if this is normal or maybe the brakes need proper time to bed. Most of those miles have been highway, so not a whole lot of braking on the vehicle yet.
Since it is a brand new vehicle it does take a bit of braking time for the brake pads and the rotors to bed, which haven't fully happened yet with only a few hundred miles of mostly highway driving. Before the bedding or mating fully happens most people don't feel anything odd because their driving is usually at slower speeds around town. They may experience a period of time where the bite isn't quite as good as might be expected, but not a pulsating feel. I'd give it another few hundred miles and see if the pulsating feel goes away. I would try not to brake hard unnecessarily for the first thousand miles.
Thanks guys, I drove it and it definitely isn't normal...braking performance doesn't appear to be impacted, but the pedal feel is not reassuring. Coming from a Jeep SRT with 14" Brembos, the Lexus stopping power is definitely there, but the feel when braking is not smooth. I did find some significant surface rust on one of the rotors, which may be the culprit, considering the abnormal feel is only in the pedal and not the steering wheel. Will clean the rust off and have her drive it for a week and if still present take it in to the dealer.
This is the first F-Sport I've driven, so just wanted to verify I wasn't going crazy.
EDIT : on closer look not sure this is rust but it may be a contributing factor.
Thanks guys, I drove it and it definitely isn't normal...braking performance doesn't appear to be impacted, but the pedal feel is not reassuring. Coming from a Jeep SRT with 14" Brembos, the Lexus stopping power is definitely there, but the feel when braking is not smooth. I did find some significant surface rust on one of the rotors, which may be the culprit, considering the abnormal feel is only in the pedal and not the steering wheel. Will clean the rust off and have her drive it for a week and if still present take it in to the dealer.
This is the first F-Sport I've driven, so just wanted to verify I wasn't going crazy.
EDIT : on closer look not sure this is rust but it may be a contributing factor.
That's interesting... looks like a high spot. Don't let the dealer repair it... have them replace the rotors and pads under warranty. I hope they agree and don't give you grief.
That's interesting... looks like a high spot. Don't let the dealer repair it... have them replace the rotors and pads under warranty. I hope they agree and don't give you grief.
Yea, I inspected it some more and it is definitely a high spot on the rotor. Oh I definitely don't want it turned...there is 150 miles on the vehicle, so it should be replaced under warranty. We bought it out of state and didn't notice until the drive home. I'll probably e-mail the selling dealer to document, but will be taking it into our home dealer.
It appears to be more of a rough spot than a high/low spot. Brake cleaner and steel wool/brass bristle brush did nothing, so it is likely a manufacturing defect. Not sure what else could cause that. I told my wife not to drive it anymore (not as a safety concern), but I'd rather the dealer see this with as few miles on the car as possible. She's already thrilled with her decision to trade in her Benz, lol.
This (above) image clearly shows material deposits of the brake pad on the rotor, and in this case, the imprint is defined by the visible layer of friction material that was transferred from the pad to the rotor when the brakes were over heated. While this happens most commonly with organic brake pads, it can also happen with some semi-metallic pad formulations, since these pads were actually designed to transfer some friction material to the rotor surface during normal use. In some cases though, the particular type of pad in use on the vehicle will wear away the high spots on the rotors, but the end result is the same; thickness variations on the rotor that cause brake pedal pulsations. In cases like this, even high-quality brake rotors will be affected, since the pad material is bonded to the rotor on the molecular level. This pad material imprint will create a higher level of resistance than the rest of the rotor causing an oscillating brake torque, steering wheel vibration and pedal pulsation.
While your new car's brake rotor is brand new the brake pad could have been in contact at the same spot on the rotor long enough to transfer some of its friction compound material to the rotor surface. It may not have the exact outline as the brake pad, but it is in the right location on the rotor and has the general size of what a brake pad would cover on the rotor. Throw in numerous days of salty air, rain, really high humidity and intense sun over-'n-over on the long boat trip from Japan and voilà - you have a rough spot on the rotor from transfer of pad material that the brake pad itself cannot remove because the spot is made from the same materials as the brake pad itself.
This (above) image clearly shows material deposits of the brake pad on the rotor, and in this case, the imprint is defined by the visible layer of friction material that was transferred from the pad to the rotor when the brakes were over heated. While this happens most commonly with organic brake pads, it can also happen with some semi-metallic pad formulations, since these pads were actually designed to transfer some friction material to the rotor surface during normal use. In some cases though, the particular type of pad in use on the vehicle will wear away the high spots on the rotors, but the end result is the same; thickness variations on the rotor that cause brake pedal pulsations. In cases like this, even high-quality brake rotors will be affected, since the pad material is bonded to the rotor on the molecular level. This pad material imprint will create a higher level of resistance than the rest of the rotor causing an oscillating brake torque, steering wheel vibration and pedal pulsation.
While your new car's brake rotor is brand new the brake pad could have been in contact at the same spot on the rotor long enough to transfer some of its friction compound material to the rotor surface. It may not have the exact outline as the brake pad, but it is in the right location on the rotor and has the general size of what a brake pad would cover on the rotor. Throw in numerous days of salty air, rain, really high humidity and intense sun over-'n-over on the long boat trip from Japan and voilà - you have a rough spot on the rotor from transfer of pad material that the brake pad itself cannot remove because the spot is made from the same materials as the brake pad itself.
So basically it won't eventually wear away on its own...
I see no reason why Lexus wouldn't replace the rotor. I wouldn't accept a turned rotor on a new car with a few hundred miles on it. Bought my 18 new out of state and had a gouged/grooved front rotor during the drive home. A pebble or chunk of metal got between the pad and rotor. Took it to my local dealer and they replaced rotor & pads under warranty. I would suggest replacing front pads with ceramic to avoid noise and excessive brake dust. It's the first thing I did with mine with no issues whatsoever with 8k miles on it currently.
So basically it won't eventually wear away on its own...
Correct. It appears to be a transfer of [some of] the brake pad's material onto the rotor's surface. This likely happened either during the shipment over from Japan or at the dealership...with help from the weather elements. You never know if the car was parked for a lengthy period of time where it was not moved...and parked in a direction where this corner of the car saw on-and-off humidity and direct sunlight over-n-over for many days.
It might eventually wear away, but it would almost certainly take a long time...much longer than any new car owner should be asked to endure the pulsating brake pedal you are experiencing. The transfer of brake pad material has caused a corrosion or etching of the brake rotor's steel surface.
You should have no problem requesting (demanding if necessary) that the rotor be replaced with a new one. The brake pad is probably okay, but to make sure the car is made whole again for you it would be best to have the pads replaced for that rotor as well. No not accept for the rotor to be turned to get rid of this spot.
Let us know what the outcome is. Good luck with it...
Hate to sound like a broken record... but I would try to re-bed them first before going to some other, more drastic options. Did that spot/pulsation develop gradually over time or was it just always like that since she got the car?
In the case you do need another option - usually some local place can “turn” those rotors for 20-25 dollars a piece.. if you remove and bring those rotors to them yourself, that is...
High spot, low spot, brake pad deposit... it could also be impurities in the steel/iron used to make the rotor. I've never seen or heard of it before but I'm sure it's possible. Rotors are an amalgam of different mateials, typically iron, aluminum, carbon and ceramic.
The fact is that no one on this board really has THE answer, all we know is that those rotors appear to be unacceptable and should be replaced under warranty. Almost all service shops preach that brake pads should be replaced along with rotors, and it should be done in pairs, so there's no reason for an exception in this case... the dealer should pony up new rotors and pads. I just hope they live up to the Lexus hype and wow you with their service.
08-31-19, 09:54 AM
Brake feel on 2019 F-Sport...
