hydrogenfu

I think this car had brakes serviced at maybe 30,000km already.. Right now it's at 100,000km..

The autoshop guy said, "your brakes are almost metal to metal, and there's some corrosion on the rotors"

When I asked do I NEED to replace all 4 rotors as well, why not just the pads? He's like "yeah, you don't want brake pads hitting corroded rotors, and you don't want uneven rotor wear...etc"...

The price is $1,000 to replace all 4 pads/rotors.... Is it really necessary to do ALL 4 rotors as well?...

BMGS

iTrader: (1)

Unless the rotors are warped or below minimum thickness specs, then they should be able to resurface them. As part of the CPO prep, the dealer resurfaced my rotors but the sad part is that when its their money, they will resurface them but when its your money, they will come up with every excuse to sell you a new set.

1Lieutenant

Can't really address the question as to whether you need rotors or not without looking at them and measuring dimensions such as thickness, run out, etc. I am not a fan of just replacing pads if the rotor has severe wear with grooves and a lip on the edge unless they are capable of being refinished.

My 2015 non F sport required front brake pads and rotors at 45K and the rears at 60K. Each was metal on rotor. I never heard the wear sensor that should have let me know the pads were at their limits. I purchased Raybestos Element 3 rotors and pads from Rockauto after careful investigation. The cost of the parts and labor was about 1/2 of what you were quoted. I have been quite happy with the results. Smooth powerful braking with no vibration or pulsation. I evaluated the front pads and rotors while the rears were being replaced. After 15K miles there was no appreciable wear on either.

jgscott

iTrader: (1)

Get a measure of the Rotor as others have said. If you were close to metal to metal the Rotor is likely scored and warped, even if it's within the min thickness still.

ViperTim

Atleast here in Sweden a resurface of the rotor is almost as much as brand new rotors.
I only resurface expensive rotors, not rotors for regular cars like the GS.

ItzFilyO

What's the minimum thickness for the rotors?

GregCanada

Looks like you are in michigan. Similar weather to here. He is likely telling the truth. rotors do not last long on these cars in northern climates. Also, you need to do some hard brakes every once in awhile to clear the rear rotors (as they barely engage during "normal" driving) and will rust much more quickly if not kept "Clean".

Southern GS owners - you wouldn't understand...

peasodos

iTrader: (1)

Unless there is a significant lip on the rotor or it’s out of spec. there is no reason to replace or resurface it, just change the pads/shims, and regrease.

I’m at 119k miles, my rear rotors are original since the car was new, still in spec. My front rotors I changed at 100k miles, even though they were still in spec.

Obviously I’ve changed my pads a few times. The key to changing pads and not the rotors is to keep using the same pads. In my case that’s oem pads.

I’ve done the same thing with previous cars I’ve owned, Honda Civic and Honda Accord. Rotors generally last a long time, unless your doing heavy breaking to cause extensive wear or warp it.

ItzFilyO

My front rotors has developed a very small lip at 24K miles but no vibration or noise. Is this normal for it's age and miles? I did a lot of hard braking during the first 18K miles or so and always stuck in traffic.

Rear rotors are still flat though and the rear pads are still thick.

peteharvey

Brand new front rotors are 30 mm thick.
The minimum recommended thickness for the front rotor is 27 mm if I remember correctly.

Normally, after your 100,000 km, I'd expect the front rotors to be replaced for sure.
However, the rear rotors do little work, so I'm surprized they need replacement.

All depends on their dimensions versus minimum thickness requirements.

peasodos

iTrader: (1)

Yes small lip is normal. The front does most of the braking, so that's why the rear rotors have a lot less wear.

peasodos

iTrader: (1)

I have a 450h so the hybrid drivetrain does some of the braking. 350 should wear down the rotors faster and also depends on how easy/heavy people are on the brakes.

jgscott

iTrader: (1)

Its actually stamped on many Rotors. Not sure if the GS though?

BMGS

iTrader: (1)

It is, just checked this morning!

peteharvey

The front and rear brake rotor minimum thicknesses below.
I only remembered the front measurements, because I only ever replaced the front rotors.
The rear rotors do little work, hence have never had to be replaced - that's why I never remembered measurements for rear rotor thickness.


Use a special pair of "brake rotor" calipers to check for yourself.
The special brake rotor calipers can overcome the "lip" on the brake rotor to measure brake rotor thickness.

NB. Conventional calipers could be used to measure brake rotor thickness, but you'd have to add two thin coins to both sides of the brake rotor, and measure the thickness of those two thin coins as well.