BMW claims rotors need to be replaced with every pad replacement?!?!

[lucid]

Originally Posted by gilbertfg

I'm no tech guru here but I'm a mechanic in the Army. Every time you replace rotors or pads, you have to change both. Due to the shape formed on both parts. If only one part was changed then the new part will wear out faster because of the irregularity of the shape on either parts.

I would think that since pad material is generally softer than the rotor material, the pad would conform to the irregularities of the rotor surface. However, you may be right that if the rotor surface is very irregular, that might cause the pad to wear out faster from then on. I don't know the specifics of how the CoF would be affected.

Regardless, people often go through more than a single set of pads at the track before replacing or turning rotors--even with track pads--as long as the compounds are compatible. That probably does not result in ultimate performance, but I haven't felt any significant loss in performance either.

[bigjae1976]

Originally Posted by lucid

I would think that since pad material is generally softer than the rotor material, the pad would conform to the irregularities of the rotor surface. However, you may be right that if the rotor surface is very irregular, that might cause the pad to wear out faster from then on. I don't know the specifics of how the CoF would be affected.

Regardless, people often go through more than a single set of pads at the track before replacing or turning rotors--even with track pads--as long as the compounds are compatible. That probably does not result in ultimate performance, but I haven't felt any significant loss in performance either.

I think it just accelerates pad wear. Regardless, I don't think most here on the forum will have much of an issue since members generally take better care of their cars.

I'd worry more about the people that wear their pads down to the backplates and wonder why their brakes are screeching.

But this rotor replacement policy was the same for E46s. That's why a typical BMW brake job (M or non-M) costs about $1000.

[JCtx]

Originally Posted by CSMRX7

My rotors measure 29.7mm on the front. Anyone know what the thickness is new?

With 30.0mm new and 28.4mm minimum, you shouldn't worry about rotors for a while. And yes, having to change rotors along with pads is ridiculous. Glad to see normal use of brakes (no tracking) doesn't eat rotors with one set of pads .

[SlammedR8]

Originally Posted by STALKER

Unfortunately in Canada brakes are not covered.

I have changed my pads with out changing rotors. Unless its covered under warranty, which its not in this case, stay away from the dealer. Buy your parts and have a good indie shop install them for you. You will save a bundle.

not true my friend

there is an additional warranty you can buy for your car for $1000 bucks, and it covers your brakes and clutch for 3 years I believe. it must be done when the car is new or less than 1 year old (or 20 000 km)

[STALKER]

Originally Posted by slammedm3

not true my friend

there is an additional warranty you can buy for your car for $1000 bucks, and it covers your brakes and clutch for 3 years I believe. it must be done when the car is new or less than 1 year old (or 20 000 km)

Yes, that is true. But in the US its all covered at no additional charge, their program in the south is more comprehensive then what we get. I spend 80% of my time in US due to work and was considering getting a US M3 before I bought my car in Toronto.

[GregW / Oregon]

Originally Posted by elp_jc

With 30.0mm new and 28.4mm minimum, you shouldn't worry about rotors for a while. And yes, having to change rotors along with pads is ridiculous. Glad to see normal use of brakes (no tracking) doesn't eat rotors with one set of pads .

+1. New pads quickly adapt to any minor rotor irregularities.

[gilbertfg]

It's better to just replace the rotors. I'm assuming since it is made in Germany, even though it's an A Spec car, rotors are one time use. It's a bad idea to resurface them. I know on my Dakota, I did it once but replaced it shortly. Rotors here in Europe are one time use since we drive faster, well I drive faster lol.

[M3 vert]

Originally Posted by slammedm3

not true my friend

there is an additional warranty you can buy for your car for $1000 bucks, and it covers your brakes and clutch for 3 years I believe. it must be done when the car is new or less than 1 year old (or 20 000 km)

+1

I paid about $2050 for 5yrs/96,000KM a few weeks ago, and this service inclusive program covers all the wear and tear items like brakes (pads, rotors etc.), drive belts, clutch (yes everything in clutch components), wiper blades and some other adjustments due to normal driving conditions

I think its worth it because even after the 4yrs/80KM warranty I have an extra year of all-inclusive service , also if you go through one complete brake job and maybe a clutch and the other stuff it pays for itself and if you sell the M before the program and warranty expires you get better resale , a win-win situation really if you ask me

[GregW / Oregon]

Originally Posted by M3 vert

+1

I paid about $2050 for 5yrs/96,000KM a few weeks ago, and this service inclusive program covers all the wear and tear items like brakes (pads, rotors etc.), drive belts, clutch (yes everything in clutch components), wiper blades and some other adjustments due to normal driving conditions

I think its worth it because even after the 4yrs/80KM warranty I have an extra year of all-inclusive service , also if you go through one complete brake job and maybe a clutch and the other stuff it pays for itself and if you sell the M before the program and warranty expires you get better resale , a win-win situation really if you ask me

You ar mixing the terms "warranty" and "maintenance". Warranties cover defective parts, maintenance plans cover service.

[STALKER]

Originally Posted by GregW / Oregon

You ar mixing the terms "warranty" and "maintenance". Warranties cover defective parts, maintenance plans cover service.

The maintenance plan in the US is also much more comprehensive unfortunately for us Canadians.
What really sucks is that my Canadian car does not get free maintenance in the US, so i have to pay for service here.

[GregW / Oregon]

Originally Posted by STALKER

The maintenance plan in the US is also much more comprehensive unfortunately for us Canadians.
What really sucks is that my Canadian car does not get free maintenance in the US, so i have to pay for service here.

That does suck. Not only do Americans pay less for their cars than Europeans or Canadians, we get the 4 years free maintenance thrown in. I can't complain!

[wrh3]

Originally Posted by gilbertfg

I'm no tech guru here but I'm a mechanic in the Army. Every time you replace rotors or pads, you have to change both. Due to the shape formed on both parts. If only one part was changed then the new part will wear out faster because of the irregularity of the shape on either parts.

But isn't that why there are bedding procedures for new pads, to get the surface to conform?

[snook]

that's some bullshite...

i wouldn't change rotors unless 1...they're cracked all the way through. 2. thickness gets down to 28mm level....or where the cross drills don't have anymore "lip"...you know..the lil countersink is gone.

[ersin]

Originally Posted by snook

that's some bullshite...

i wouldn't change rotors unless 1...they're cracked all the way through. .. .

OMG, No! I would change the rotors ASAP at any sign of cracking. I'm sure bad things can happen well before they crack all the way through. These are drilled rotors and any type of rotor crack is not good.

[SenorFunkyPants]

Originally Posted by bigjae1976

But this rotor replacement policy was the same for E46s. That's why a typical BMW brake job (M or non-M) costs about $1000.

Its certainly not a worldwide policy...My E46 m3 still had its original front disks at >40,000 and 3 sets of brake pads....although they must have been up for changing soon.

[TheRealDC]

Hmm - my E46 did ~90k miles on the original discs all round. Admittedly the rears were definitely needing replaced when I passed it on, but I now have some steering wheel judder when I break from over 50mph on my current E92. Car is booked in for investigation next Wednesday, but I'll be mightily unimpressed if -

1. The discs do need replacing at only 24k miles.
2. I have to pay for them.





DC

[frankzlin79]

According to the service manual, what is the recommended mileage to change out your brake pads (and now, I guess the rotors too, if it's covered under U.S. warranty)?

[TLud]

Originally Posted by frankzlin79

According to the service manual, what is the recommended mileage to change out your brake pads (and now, I guess the rotors too, if it's covered under U.S. warranty)?

There is no recommended mileage. It all depends on usage. The pads have wear sensors, and the car will let you know if they need changing.

[Pete The Greek]

when you change the brake pads, you have to change the rotors too with BMWs, ive done it plenty of times on my 3series

[Dascamel]

Originally Posted by ersin

OMG, No! I would change the rotors ASAP at any sign of cracking. I'm sure bad things can happen well before they crack all the way through. These are drilled rotors and any type of rotor crack is not good.

Small fractures aren't the end of the world, fairly common around the drilled rotor holes. Anything, more than that yes replace. Our factory rotors are fairly durable. The soft pads are far more of an issue. Even though free for us, I'm about to get rid of the pads for track days and maybe even the street.

If the op is planning to get R comp next summer, keep the rotors for now, just change the pads. If his measurements are correct he still has plenty of life left on the rotors. Just be sure to properly bed the pads to the rotor before any aggressive driving.

Once the R-comps arrive, then time for for pads and rotors. At that point since his brakes are not covered, aftermarket options start to make more sense.

[gr8000]

Originally Posted by Dascamel

Even though free for us, I'm about to get rid of the pads for track days and maybe even the street.

Can you use aftermarket pads (like pagids) and make use of the OEM pad wear sensor? Will the system calculate correctly remaining pad life?

[Gearhead999s]

Originally Posted by gr8000

Can you use aftermarket pads (like pagids) and make use of the OEM pad wear sensor? Will the system calculate correctly remaining pad life?

I use the the wear sensors with my Hawk's with no issues.The milege remaining has to be reset to be anywhere near accurate.I had a thread posted on here about resetting the milege on the I-Drive.

Here is the post about resetting the pad life.

http://www.m3post.com/forums/showthread.php?t=295031