Ebabe

I took my 2015 Lexus Gs 350 in for. A grinding sound. Coming from my rear brakes. The dealership looked at it and said that I needed new rotors and pads in the back. I approved the repair.Picked up my vehicle Upon completion and a couple days after driving, it noticed a fluttering on my briake Pedal. What would be the cause of this?

EAST

Have you braked hard since getting the rears done? Maybe you got some pad build up after a hard brake (and keeping the brake pressed).

General question:
Do dealers bed in brakes? Or just tell people to take it easy on the brakes for the first few hundred miles?

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cnc369

since you stated your rear pads and rotors have been replaced, the pulsation issue is coming from the fronts. your front rotors are warped or have excessive runout.

cnc369

why would this need to bed in brakes need to be done on factory oem parts? the bedding in of brake pads and rotors is something that is done on shi tty aftermarket pads and rotors, the process helps take off the protective coating especially on shi tty aftermarket pads as they cause a groaning/moaning noise when you come to a stop. but then again some people swear by the performance of these aftermarket products.
i've never had to bed any factory pads or rotors in all the cars that either belonged to myself or friends.

EAST

That's possible. I don't think I've ever bought OEM stuff before for prior cars, either because of price or excessive dust, and just went with what "the forum" at the time recommended. So it was just a procedure I picked up along the way. I'll research a bit for my next brake change to see what the consensus is.

That said, are OEM parts immune to build up from an emergency stop/heavy braking? Though it's possible, as another posted suggested, that the front brakes just need to be done.
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cnc369

the excessive dust issue is due to softer brake pad material. toyota likes to use advics as their oem supplier, and yes that pad material throws out dust like crazy but it has almost near zero brake squeel/squeek issues. if you want a better quality perfomance brake pads go with akebonos or hitachi. both of which have are oem suppliers for other japanese auto makers, have little brake dust issue or brake fade issues after repeated hard braking, you'll probably put heat spots on the rotors before you getting noise or performance issues with the pads. the only issue i found with hitachi brake pads are they are impossible to get even eventhough it comes factory on nissan and infiniti vehicles as their oem, but when you get a set of pads from the dealer parts counter they'll hand you a set made by akebono.
and no, no brake pads are immune excessive harsh braking issues, even the mercedes slr had brake squeels if the driver was harsh on the brakes. but once the owner get the quote for the pads and rotors they suddenly can live with the noise.

Ebabe

No I did not break hard. I took my vehicle back to the dealership and asked if there was a possibility that the new rotors they had installed could be defective or warped. I was told that the mechanic did note an intermittent fluttering in the break pedal but it was not a cause for concern. They went on to say that I now needed front break replacement since the flutter in my pedal was indicative of an issue with my front breaks. They even told me that if it were my back breaks I would feel a vibration in my drivers seat! This sounds like total BS to me. Somebody please clarify where i would feel the issue, My guess would be either the pedal or the steering wheel, not under my seat??

Tom44

I suspect your rear rotors and pads are fine.
If there was no flutter in the brake pedal before you dropped off the car then here is my guess as to what happened:

The tech either took the car out for a test drive and did some hard braking which resulted in uneven brake deposit on the rotors and hence the flutter OR they took off all 4 wheels (to inspect the front ones?) reinstalled them with improper torque (using a torque gun) and then did some hard braking. The correct way would be to hand torque to spec in a star pattern ensuring even torque between the wheel and the hub.

Same thing happened to me at least twice at the dealership and the wheels are almost always not torqued evenly to spec (I have to redo it myself before I drive the car) and honestly the dealer will never admit their fault. I would suck it up at this point and have the fronts replaced at some point. When you do have them replaced redo the wheel torque correctly with a hand torque wrench before leaving the dealer. Also instruct the dealer NOT to test drive the car: tell them you have noted the mileage and you do not want anyone to drive it off the dealership. Only to the service bay and back to parking area. I'm serious: you have to be that specific.

Sorry you have to deal with this.

GSJ350

The over torquing of wheels is often over looked and im glad to see that someone else is mindful of it. During my 10 years of work at discount tire co, this was always a talking point to which proper torque for the vehicle was always stressed. When lug nuts are over torqued it creates an issue where the disc cannot expand (because of heat) properly and evenly. The over torqued disc expands in a wave to which you feel as being warped in the pedal. Went to a hole in the wall tire shop to get a rotation, brakes felt warped after that and then i remembered what i learned at discount. Re adjusted the torque my self and problem went away.