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Hello,

I want to change my break pads to minimize dust. Have read most of the threads about it and i decided to go with Porterfield R4S Pads.
I called the shop today to ask for a quote to install them and they told me i need to get new rotors as well if i am changing the pads.
Is this true?
 

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No.

They should do the measurements first on the rotors with a caliper and see if it is within the specs or not, then the mechanic can recommend if a rotor/disc change is needed or not. Do a search on the different values of the brake disc as measured by caliper (in mm) for the different R171 models (do a search on threads started by Easty).
 

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If your mileages close to 40K MB recommend to change pads and rotors.most probably you just need the front axle only. Also you may as well change your brake fluid to get a fresh start.
 

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If your mileages close to 40K MB recommend to change pads and rotors.most probably you just need the front axle only. Also you may as well change your brake fluid to get a fresh start.
AFAIK Mercedes does not recommend a change of rotors at any specific mileage. Rotors are changed when they are near their minimum spec or are warped, overheated, etc. That can vary widely in mileage from driver to driver. Measure them and make your decision. Brake (not break) fluid should be done every two years regardless of any brake work that you do or don't do.

Len
 

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Discussion Starter #6
Thank for the replies guys.
My car only has 17,000 miles so i dont believe it needs new rotors. -- What i understood from the guy at Meineke is that if i was going to put new ceramic pads, i needed to put new rotors as well since they wear differently???
Just want to make sure i'll be ok just changing the pads
 

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IIRC, Arno (PropDr) has Porterfields on his 55 and I don't recall him mentioning a change of the rotors/discs.
 

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Never heard of that before - rotors either wear evenly, or don't - if they are warped, they need to be replaced - or if they are below minimum spec, which as I recall was 3mm.
 

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Get the Akebono Euros. Amazon has them. You can easily eyeball the rotors to determine if they need replacement. Usually if you haven't worn the old pads down to the metal, the rotors will be OK.
 

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Never heard of that before - rotors either wear evenly, or don't - if they are warped, they need to be replaced - or if they are below minimum spec, which as I recall was 3mm.
That's typically the minimum specs on pads, 2 or 3 mm. Rotors are much more, typically in the 25mm range. I can look it up if anyone really needs to know. Just going by my sedan, pads are 2mm all around, front rotors are 25.4, rear rotors are 8.3 - all in mm.

Len
 

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If rotors are flat and greater than the service limit (for my R170, the spec says 23.5mm is the service limit), then fitting new pads does not require new rotors.

Of course, if the rotors are scored they should be resurfaced for the new pads, which might bring them under the service limit if they're close. For instance, my pads have 50% material left but at 123K miles, the rotors are at the service limit—the next time I put pads in, I'll change the rotors too.

Any service shop telling you differently is trying to make an extra buck, IMO.
 

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That's typically the minimum specs on pads, 2 or 3 mm. Rotors are much more, typically in the 25mm range. I can look it up if anyone really needs to know. Just going by my sedan, pads are 2mm all around, front rotors are 25.4, rear rotors are 8.3 - all in mm.

Len
See post #3 with link above.
 

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What I have noticed about the MB rotors installed on mine was like pre-matured grooves showing on the rotors like it was coming from the pads and this was as early as 2k.
 

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Rotors don't wear unless serviced?

I thought rotors don't wear, just the pds wear? To my (limited) knowledge, the only way a rotor will reduce in thickness is if they are "turned" (aka "planed" or "shaved") to remove grooves. This is when you have to pay attention to the minimum thickness since turning the rotor removes surface.

Do I misunderstand?
 

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Yes, you misunderstand. :)

Pads rub against the rotors wearing both parts. Typically rotors will last two or more sets of pads, but the rotors do wear, faster with some pads. The general rule of thumb is that Mercedes rotors should never be turned because they typically don't ever need to be turned plus they hardly have enough "meat" on them to make turning worth it. I have owned Mercedes cars for 30 years and have never had to have a rotor turned. So there are specs for both pads and rotors. You can see the wear on the rotor by observing the little ridge that forms near the edge.

Len
 

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Thanks for clarifying! It all comes back to me - the outer ridge that forms is the clue!
What are available for brake pads other than the factory pads?
I have a 2005 SLK55 AMG with out the optional w030 performance option.
I have called around today and found out the high dusting factory pads from MB are exspesive and make alot of black dust that sticks to everything.
I went on line and saw EBC yellow pads and bunch of other options out there.
BUT WHICH ONES TO BUY??????

WHO HAS HAD GOOD LUCK WITH ANY OTHER PAD??
Where did you get them and what part numbers? At what price point?
Were they any better worse or the same as factory pads??
 

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What are the Specs for Rotors?

Yes, you misunderstand. :)

Pads rub against the rotors wearing both parts. Typically rotors will last two or more sets of pads, but the rotors do wear, faster with some pads. The general rule of thumb is that Mercedes rotors should never be turned because they typically don't ever need to be turned plus they hardly have enough "meat" on them to make turning worth it. I have owned Mercedes cars for 30 years and have never had to have a rotor turned. So there are specs for both pads and rotors. You can see the wear on the rotor by observing the little ridge that forms near the edge.

Len
I'd like to know the spec for rotors for my 2001 R170 449. I saw you mentioned the rotor specs in a communication (quoted) that there are rotor specs but I can't find them anywhere in my book and online. (Pelican Parts didn't know and told me to ask in the SLK Forum.)

Please tell me what they are and where to look for information like this. Thank you!
 

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I'd like to know the spec for rotors for my 2001 R170 449. I saw you mentioned the rotor specs in a communication (quoted) that there are rotor specs but I can't find them anywhere in my book and online. (Pelican Parts didn't know and told me to ask in the SLK Forum.)

Please tell me what they are and where to look for information like this. Thank you!
Here are the specs for my 2003. I would think yours ought to be the same.

Front rotors - 22.4 mm
Rear rotors - 7.3 mm
Pads - 2 mm for all
Brake sensor will typically trip about 3 mm.
 

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Hello,

I want to change my break pads to minimize dust. Have read most of the threads about it and i decided to go with Porterfield R4S Pads.
I called the shop today to ask for a quote to install them and they told me i need to get new rotors as well if i am changing the pads.
Is this true?
If I shop tells you that you need new rotors after 17,000 miles they are trying to sell you something you don't need. This is typical of almost every shop I know of. As long as they are not warped, and you will know this if you feel the car braking unevenly as you come to a slow stop, you most likely don't need rotors.
And if you did the car would tell you so anyway.
For pads,, go with the red or green from EBC.
Just my 2 cents.
 
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