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2005 E320 CDI 170k
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Discussion Starter · #1 ·
Hello,

I am looking at a brake job on my '99 E300TD. After looking at the DIY section, it seems pretty straighforward (I have done many disc brakes in the past) but the article did not address whether the rotors need to be resurfaced or not. When I worked in the business a long time ago, we always resurfaced them just so the pads would seat. Any thougthts???

:)
Warren
 

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'95 E300 DIESEL, '91 600SEL, '92 600SEL
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Do not resurface rotors on a MB unless want to have chassis vibration. Just inspect the rotor for thickness at each tire rotation and replace the rotor (and the pads obviously) when it is reaching minimum thickness as stamped on the edge of the rotor surface.

The rotors are designed to be disposible, hence their unusually low price.

Just get a good set of aftermarket ones such as ATE, Zimmerman, Balo, etc. Do not settle for the Autozone or Pep Boys items that come from China or who knows where.
 

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1994 E320 Wagon,1999 E320 Wagon,2000 E 320 Wagon, MGB Track/Rally, ,1988 300E ,more....
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Not enough meat on

the mb rotors,if the surface is mirror smooth you can break the glaze with a sanding pad and 120-140 grit paper in a cross hatch pattern on both sides and then dish soap and water wash followed by a good spray of brake cleaner.
If they are not smooth,yo will need to replace the rotors.autohausaz.com or if you track the car diversified cryo .
have fun
:bowdown:
not unusual to get at least 2 uses out of a set of rotors.
 

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1994 E320 Wagon,1999 E320 Wagon,2000 E 320 Wagon, MGB Track/Rally, ,1988 300E ,more....
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6,019 Posts
$50

for a pair of rear rotors off of ebay is like buying a maf off of ebay.Most likely chinese clones that can damage more than a fake maf,they can damage your life.
Why not spend the money and get a real set of rotors if you have no serviceable life left on the installed ones?
:bowdown:
 

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2001 E320; 2002 ML500
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When it comes to brakes, I don't mess around. Buy a quality German made rotor; they are not that expensive.
 

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1922 Ford T no OBD, no ECU, no SCN
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37,855 Posts
Actually brake rotors is mild steel. German engineering doesn't apply much here.
I bought aftermarket rotors for my AMG from Canadian manufacturer selling on ebay.
Having them galvanized makes good impression with over-sized wheels.
 

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'04 G55 '80 280GE '99 S420 '98 E320 2011 E350 2016 GLA250
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I understand I am but a Lowly Mechanical Temple Monkey, but I don't see what is so "magical" about MB rotor which causes many to say "Oh, you CAN'T turn MB rotors.."

I have searched WIS, and have yet to find any warning to that effect.

As long as they are still within the specified Service Limit of the rotor, what is the reason to NOT turn them??

I have, and others I know, had MB rotors turned with ZERO problems.

Perhaps this is some Fable passed down through the generations??

The Scientist in me would love to see any hard data, if there is any.

Cheers
G
 

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'95 E300 DIESEL, '91 600SEL, '92 600SEL
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I understand I am but a Lowly Mechanical Temple Monkey, but I don't see what is so "magical" about MB rotor which causes many to say "Oh, you CAN'T turn MB rotors.."

I have searched WIS, and have yet to find any warning to that effect.

As long as they are still within the specified Service Limit of the rotor, what is the reason to NOT turn them??

I have, and others I know, had MB rotors turned with ZERO problems.

Perhaps this is some Fable passed down through the generations??

The Scientist in me would love to see any hard data, if there is any.


Cheers
G
The stock factory rotors are somewhat prone to warping IMO, even when new.

Turning them (a.k.a. resurfacing) only takes off more meat from which there isn't enough to go around considering the heft of the cars. I've been able to warp almost new rotors from just one single hard brake application.

However, if you bead in (heat cycle) the rotors and pads right after installation, they seem to be far more resistant to warping. Also, Balo and Zimmerman branded rotors are least prone to warping. As far as longevity, I've had the best luck with ATE grooved rotors (the star shaped groove kind).

Personally, I think turning rotors on a MB are a waste. The cost of turning a used rotor is about the same as a new unit.
 

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2001 E320 - Brilliant Silver/Ash: 107,000+
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I understand I am but a Lowly Mechanical Temple Monkey, but I don't see what is so "magical" about MB rotor which causes many to say "Oh, you CAN'T turn MB rotors.."...Cheers G
LMAO, "Lowly Mechanical Temple Monkey"? That's a good one and you hardly fit into that category. If they can be turned, so be it, but I have always heard the same thing (can't be). If you have searched this topic on the WIS and found no evidence to the contrary, that is good enough for me. Thanks for the insight. Cheers, or is it Beers? to you! ;)
 

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1922 Ford T no OBD, no ECU, no SCN
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Got to love the Internet. You don't know the day of place where surprise might hit you in the head.
"Lowly Mechanical Temple Monkey" -got to memorize this one :D
Coming to non-turnable rotors it is not only MB and not only last generation of cars that makes skinny rotors that don't have enough thickness for the machining. I think the mentioned economy is one reason, but in the past I've seen lot of butchered machining jobs, so why take the risk and hassle?
 

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2001 E320 - Brilliant Silver/Ash: 107,000+
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LOL Kajtek1, I see you found that funny also. Now maybe we can discuss the guy from Poland who after drinking a few Polish beers and who raises his MB with a forklift to polish his differential? :D
 

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'04 G55 '80 280GE '99 S420 '98 E320 2011 E350 2016 GLA250
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sbaert

You obviously know way more about brakes than I, so I am in no position to disagree, but I keep hearing this "MB rotors don't have enough 'meat' on them to turn".

My point is, how does the rotor know if it is a PAD or a MACHINING device which is wearing it down??? Yes, I could understand if the rotor had some special coating (like a G-wagen Caliper piston, which can't be polished or sanded) which would be removed while turning...., but they don't. They are solid metal.

And cost?? I recently had the old G's rotors turned for $7.50 each!, so I disagree that turning cost is equivalent to new rotors, (especially since G rotors are $110 EACH, the turning/new ratio is obvious.)

You also speak of "Heft" --remember the G is nearly 6.000 pounds, I have never had any warping issues in the last 10.000 miles, and the last cut was to 0,5 mm over service limit of 14mm.

Am I an "anomaly" of driving? Perhaps. On the W210, and W140, I JUST replaced the front pads on both---> Over 100.000 miles on the ORIGINAL PADS! The rears?? Both cars' pads were near NEW thickness at 120.000 miles:
http://www.benzworld.org/forums/w140-s-class/1379576-photo-diy-rear-brake-pad-change.html

I'm sorry I am "kicking the dead horse" on this topic. I am a believer in "facts", and if someone can show me evidence otherwise, I will follow "simple logic" (if a rotor is above service limit--whether from PAD or OTHER wear,) then it is safe.

The same logic applies to Pads. I've heard a similar myth of "don't let your pads get down to service limit". Is a pad at 15mm cause any more friction on a rotor than a 3mm pad? Probably not. Yes there may be heat-synch or other variables, but if a MB engineer says 3mm is JUST as safe..... so be it.

Anyhooo, enough babbling from the Temple Monkey...
 

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Goodness! All this banter over something so simple?

There is nothing that says you "CANNOT" resurface MB rotors.

However, MB does not recognize it. Nowhere will you find them approving the process. If a rotor does not meet spec, it is to be replaced, not resurfaced. That's just the way they do it.

Now, should YOU wish to resurface a rotor and you know that it is thick enough that you can (1) turn it enough to yield a new, smooth surface and (2) *still* have enough thickness left over that it will not wear beyond minimum thickness during the life of the new pads, then you may choose to follow that option. Of course that also means that if you pick them back up from the machine shop and they ended up having to resurface them to the minimum thickness, you now have one or more doorstops, because within a week or two of use they will be below minimum thickness. ;) And you'll naturally have to pay them and still have to buy new rotors.

Moreover, you will be required to remove the rotors from the car and take them to the machine shop. No reputable indie or dealer will resurface MB rotors. (And why would you take your car to a disreputable indie or a place like Midas anyway?)

Nevertheless, since MB's recommendation is to replace and not resurface, that is certainly the best course for most people to take. And if you're trying to save time and money by DIY, having to remove all the rotors, load them in another vehicle, take them to the shop and either wait around or come back another day -- while your car sits on jackstands -- is likely not doable for many of us. And new rotors for regular old MB vehicles (Mogs, G wagens and AMG models aside, of course) are indeed quite affordable. You can buy all four rotors and all 8 pads for less than the dealer will charge you to replace F&R pads, so if you're going to DIY that simply makes more sense. And if you're going to the dealer or indie you're paying through the nose anyway, and they won't resurface, so in that case you simply don't have a hand to play.

Just my .02.

Take care and enjoy the ride,
Greg
 

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I have a E-320 and A C-320 which use same size rotors. I bought new set of rotors and then turned old set which I use when next set needs to be turned. I rotate like this until one set drops below allowable specs. then purchase a new set. I have never noticed a difference in German vs other steel.
 
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