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I have a 2005 E 320 CDI. I'm about to change my brakes (for the second time since I bought the car new) and the rotors (1st time). Need help on upgrade the rotors and brakes with some good aftermarket (near Brembo quality) equipment. Your help is appreciated.:bowdown:
 

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Rotors and pads must always be replaced as a set. Re-using rotors or turning rotors is prohibited and will result in reduced pad life or warping of the rotor.

I take it from your post that you are wearing out rear pads at a fast rate. This is due to being too gentle with your braking habits, increase brake pressure on the pedal (yes be more aggressive) and the pads in the rear will be biased out of the braking systems logic (EBD proportioning), resulting in improved brake pad life and performance.

It may be hard to believe but OEM rotors and pads are in fact performance rotors. They use a softer iron which is cooled more slowly resulting in an iron alloy that has superior heat disipation characteristics and a reduced probability of warping thanks to fewer carbide inclusions. Harder rotors have higher amounts of carbide inclusions which causes localized hot spots in the rotors structure thus increased probability of warping and poorer heat disipation.

The OEM pad material is of a type that has very good friction characteristics when cold thru the medium heat ranges. If your driving is more aggressive or do not require good cold braking properties (majority city driving), an OEM rotor and a more aggressive pad combination may be suited for your needs.

If your driving has a 50/50 mix of city and highway you may want to stick with OEM type pad material to maximize cold pad performance.

DB
 

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Thanks DrivBiwire,
Since that I do about 30/70 city/hway, I might go with the stock rotors and ceramic pads.
 

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Thanks DrivBiwire,
Since that I do about 30/70 city/hway, I might go with the stock rotors and ceramic pads.
Have you ever faded your brakes under the driving conditions you describe? If you haven't then maybe you should think about OEM pads. Typically you will not fade your brakes unless you are driving on the track.

Why go to ceramic if you are not fading the brakes?

Jeff.
 

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Prohibited??

Rotors and pads must always be replaced as a set. Re-using rotors or turning rotors is prohibited and will result in reduced pad life or warping of the rotor.
Prohibited?? Are you saying that the MB recommendation is to replace both rotors every time pads are replaced ... who would 'prohibit' turning? Or are you saying the wear (generally) of a set of pads will reduce the thickness of the rotors to below the minimum spec?
 

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Prohibited?? Are you saying that the MB recommendation is to replace both rotors every time pads are replaced ... who would 'prohibit' turning? Or are you saying the wear (generally) of a set of pads will reduce the thickness of the rotors to below the minimum spec?
Once the rotors go thru a set of pads, the rotors are turned thus removing even more metal, new pads installed the rotors will more than likely not last thru the 2nd set of pads without warping.

Now you just wasted Labor + Pads + $$ of turning the rotors ultimately costing you MORE money vs if you had just installed new iron in the system along with the new pads as intended by MB and the brake system suppliers.

Also Rotors are entirely dependant on mass for providing the stopping power to your car. Turning used rotors and installing new pads presents a higher risk of fade and inability to perform up to the original safetly levels.

Increased risk of warping, cracking and damage can result from failing to install new rotors with a set of pads.

Rotors are cast so they are lighter and softer to provide superior braking. Modern cars simply do not provide the additional iron in the rotors structure that can permit turning or use over several sets of pads. This is driven not by production costs but reductions in spinning mass, safety, and brake system performance in a specific applications when used in conjunction with systems like ESP, ABS, EBD, EDL etc which all demand more from a set of brakes.

Put another way, installing new iron with new pads insures optimal mass and energy absorbtion capability for the cars brake system.

So again the rotors present just enough mass to last the life of a single set of pads.

DB
 

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Once the rotors go thru a set of pads, the rotors are turned thus removing even more metal, new pads installed the rotors will more than likely not last thru the 2nd set of pads without warping.
I haven't worked on MBs in a while, but a micrometer will tell you if the rotor is spec'ed to last and therefore will last through another set of pads.
Now you just wasted Labor + Pads + $$ of turning the rotors ultimately costing you MORE money vs if you had just installed new iron in the system along with the new pads as intended by MB and the brake system suppliers.

Also Rotors are entirely dependant on mass for providing the stopping power to your car. Turning used rotors and installing new pads presents a higher risk of fade and inability to perform up to the original safetly levels.
Yea, not "oroginal safety levels", but if after turning the rotor is thicker than the spec, it's safe according to MB.
Increased risk of warping, cracking and damage can result from failing to install new rotors with a set of pads.

Rotors are cast so they are lighter and softer to provide superior braking. Modern cars simply do not provide the additional iron in the rotors structure that can permit turning or use over several sets of pads. This is driven not by production costs but reductions in spinning mass, safety, and brake system performance in a specific applications when used in conjunction with systems like ESP, ABS, EBD, EDL etc which all demand more from a set of brakes.

Put another way, installing new iron with new pads insures optimal mass and energy absorbtion capability for the cars brake system.

So again the rotors present just enough mass to last the life of a single set of pads.

DB
It's certainly true that replacing the rotors with each set of pads is safe, and you'll get better braking performance. I certainly understand how this stuff works (it's not just energy absorption capability, btw, it's also a function of heat dispersion capability, but I digress). But that's not what I was trying to ask.

If it's prohibited, by whom? If it's merely not recommended, what is the precise manufacturer recommendation?
 

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I have a better one for you Show me where it says you can turn them from an official Mercedes manual or publication, then you will find where it says it is forbidden.

You are confused in regards to rotor specs.

Brand new rotors are already at the "Minimum" thickness to permit the installation of new pads. The minimum thickness is in regards to the rotors requiring replacement despite pad material not yet reaching its minimum thickness.

If rotors reach the wear limit first, pads and rotors get replaced.

If the pads reach the wear limit first pads and rotors get replaced.

If the rotor is still above the wear limit in no way is this an indication that it can still provide safe, reliable braking for the life of another set of pads. Again you are confusing older generation braking systems with modern ones.

Again even if the rotor is above it's "wear limit", The rotor is still insufficient in thickness to permit the installation of new pads and provide a safe and reliable usable service life.

DB
 

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For what it's worth, my SA told me some time ago that the rotors used in more current w211's are different from the old spec and typically last thru two sets of pads with no problems. He also said that probably wouldn't apply to aggressive drivers who tend to go thru pads and rotors in a very short time.
 

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For what it's worth, my SA told me some time ago that the rotors used in more current w211's are different from the old spec and typically last thru two sets of pads with no problems. He also said that probably wouldn't apply to aggressive drivers who tend to go thru pads and rotors in a very short time.
It's been 15 years since I was a mechanic, and I've never owned a MB before, but this is consistent with most recent cars. And, this is exactly the situation I found with my BMW E39 528 ... after one set of pads, a new rotor is still well above minimum thickness specs, and turning/reusing the rotors on a second pair of pads provided perfectly acceptable brake performance. After the second set of pads, the rotors were just at/just below minimum thickness (i.e., perfectly matched to two sets of pads).

This is why I asked, "prohibited by whom?" I certainly am not a MB expert, but that doesn't make me a novice re brakes and braking systems.
 

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If the rotor is still above the wear limit in no way is this an indication that it can still provide safe, reliable braking for the life of another set of pads. Again you are confusing older generation braking systems with modern ones.

Again even if the rotor is above it's "wear limit", The rotor is still insufficient in thickness to permit the installation of new pads and provide a safe and reliable usable service life.
If this is true, then MB has completely redefined the 'rotor minimum thickness' specs. Some manufacturers provide both a minimum thickness for operation and a minimum thickness for for relining (new pads) - perhaps we're talking about different numbers?
 

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I can add something here, typically any temper that exists on a cast iron and heat treated rotor is restricted to within a few thousands of the surface, once you turn rotors you remove that heat treated material and get into the softer material which results in a reduced life and usually reduced breaking performance....this is why rotors will go for 50k miles with little wear but wear drastically within 20k miles after new pads are applied....thats not just a Mercedes trait....its the same with all cars......turning rotors makes little sense now that the replacement parts are so inexpensive as was suggested earlier.
 

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Rotors and pads must always be replaced as a set. Re-using rotors or turning rotors is prohibited and will result in reduced pad life or warping of the rotor.

DB
Well, at the dealership, we don't replace rotors with every brake job. We measure the rotors with a digital caliper or micrometer and if they are within about 2mm of the spec we replace them. If they are not close to the Min. Thickness, we just put a new set of pads on. We NEVER turn rotors at the dealership.
 
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