SL/R231: wrong front brake pads
Thread Starter
Senior Member
Joined: Jun 2020
Posts: 257
Likes: 85
From: Newbury Park, CA
2016 SL400 & 2021 C300
wrong front brake pads
So I ordered Power Stop dustless pads and since I have the sports wheel package with 19 inch AMG 5 spoke wheels, I ordered the Z23-1688 pads for the front. My installing mechanic calls and says they do not fit, too big. I contacted CARiD and they checked using my VIN and said I ordered the correct pads. I checked the dealer invoice on the new dusty pads the dealer installed recently, checked the OEM part number and discover they seem to be the for non sport wheel option. My mechanic says this happens a lot. Suffice it to say I am not thrilled but I ordered the Z23-1670 pads and am hoping these will fix the problem. Apparently, there are two disc sizes used on our cars, one is 360mm and the other is 342mm. CARiD wanted me to jump through hoops to convince them that the ones sent do not really fit. While totally not unreasonable, once the car has been put back together and is ready for me to pick it up with only rear pads installed, it is hard to expect the mechanic to jack up the car again, remove a wheel, take pictures, measure the disc, etc. I agree with him, there are only two sets made for the front wheels and if one is too big, you undoubtedly need the smaller ones.
Super Member
Joined: Jul 2018
Posts: 563
Likes: 171
From: Nothern Georgia, U.S.A.
'17 SL450, '25 Lyriq, '25 Sonata Hybrid, '96 Corvette GS coupe
This is why I haven't ordered mine yet. The '17+ cars all come with a "sport" package, but it's unclear exactly what is included in that package...it may be that the 360mm rotors are part of it, but I won't know without pulling a wheel and measuring.
Thread Starter
Senior Member
Joined: Jun 2020
Posts: 257
Likes: 85
From: Newbury Park, CA
2016 SL400 & 2021 C300
I did not send back the larger front brake pads that I ordered (PowerStop Z23-1688) that did not fit my SL400. I have the smaller rotors so bought the Z23-1670 ones and they were installed last week. I had already had the rears replaced last month. If anyone is interested in a set of Z23-1688 pads for their front rotors, I have a set I cannot use. I ended up with a set of the smaller pads that were lightly damaged in shipping, so had them replaced with another set. I also have nearly new OEM pads that I replaced if anyone is interested. I bought my car as a CPO and the dealer replaced the old pads with new OEM pads, front and rear.
Thread Starter
Senior Member
Joined: Jun 2020
Posts: 257
Likes: 85
From: Newbury Park, CA
2016 SL400 & 2021 C300
The advantage to the smaller brakes, if they have close to the same stopping power, is they are lighter resulting in less unsprung weight at the wheels.
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Joined: Dec 2015
Posts: 1,636
Likes: 522
From: Hagerstown MD
2015 SL400; 2019 X5M40i
Perhaps but the bigger brakes should perform better along with the drilled rotors. Not sure what the weight difference is but I doubt it's more than about 1-2 lbs.
Thread Starter
Senior Member
Joined: Jun 2020
Posts: 257
Likes: 85
From: Newbury Park, CA
2016 SL400 & 2021 C300
True! I wonder how easy it would be to convert to the larger rotors and pads. Having the 19 inch AMG wheels, I am sure they would fit fine. I am guessing you would have to get different calipers and mounting hardware to make it work, which would probably cost more than it would be worth.
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