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So I will be getting new front and rear pads done in the next week or so. The dealer had recommended replacing the rotors on all 4 corners regardless of condition at the same time. But I plan on using an indy and they will check the condition of the rotors first. Currently I don't sense any vibrations while braking in the wheel or in the seat. Other than measuring them with a caliper, can you gauge the condition by feel?
On the front rotors, there is a small lip at the outer edge and there seems to be a slope coming off the center indicating they've gotten some wear. The surface between the center and edge seems smooth. On the rear, there is no perceptible lip on the outer edge or slope coming off the center. Just trying to have an idea of what to expect before I bring them in.
The only way to really tell is to measure them. I’d find out what the actual minimum is before having them replaced. You should be able to get 2, maybe 3 pads out of a rotor.
... they always do. Rotors are "free money flow" for the shops as they don't require much additional work to the pads replacement, while generate income not only on labor, but also on part markup.
This way shop can make $500 in less than 1 hr.
For me rotors are lifetime item as they seem to last at least 400,000 miles.
The min thickens is always stamped on them. Look at smaller cylindrical part outside where rear have E-brake shoes.
Big lips develop with less than 50% of wear, so I grind them at this point.
I concur with everyone, Fisch. Measure to be sure, and if good maybe a quick resurface and good to go. If you start with a clean surface the pads will have a better chance of transferring material to the rotor and bed properly, so you can continue with your smooth braking.
2007 mercedes e63, 2006 bmw 530 Xi with Mtech kit , 2005 ford expedition
The only bad thing is if the rotors are slightly worn when u slap new pads on you mite get sum vibration... That was my case When I did my brake job on my e63 I had the same outer lip on rotors..the Mechanic mentioned thst I mite get a lil vibration when the new pads go on and that's exactly what happened
If you did decide to replace your rotors you may want to consider upgrading to slotted discs. From my experience and research it seems they provide many of the benefits of cross drilling without the potential for cracking.
Thanks for the input everyone. I will definitely ask for a measurement because I can't see or feel the condition of the back side of the rotor. In regards to grinding, I thought the resurfacing of cross-drilled rotors like the ones on the front was a no-no due to chipping. Also, some indy shops I have talked to have to send rotors out for resurfacing so the labor cost to remove and reinstall and resurface isn't that much more than a replacement. If I was doing it myself that would be another story.
I was referring to grinding the lip, when the rotor still has lot of thickness left. MB does not have much thickness for turning the rotors, so if you have deep groves - they call for rotor replacement.
Grinding front rotors is a breeze. When you angle grinder at good angle - the grinding will start turning the rotor for even finish. Rear is more difficult.
For me rotors are lifetime item as they seem to last at least 400,000 miles.
Is your E250 a diesel? I just checked the brakes and pads on my 2011 E350 Bluetec diesel, and at 54K miles they were like new.
The diesel has so much engine braking that the brakes are only lightly used, and could be a lifetime item.
On the other hand, my SL55 at 94K has a good sized lip on the massive rotors, 5K mile pads half worn, and will likely need the grinding you mention soon. Still above minimum thickness.
If your rotors are smooth without any grooves or bad wear id keep them... otherwise replace them. I did my fronts over a month ago..and i replaced rotors and pads. But my rotors were bad.
Replaced the pads about a month ago. The rotors had groves on them. With new pads and bad rotors, there is some vibration during braking but not too bad.
Had that happened , and that happened to be the OEM akebono pads that i used on old rotors with grooves.
waisted 100 bucks basically.
Shortly after some time it started vibrating pretty badly when applying brakes, so i went ahead and bought new pads AND rotors.
I use pads and rotors from the local Mercedes dealership, so they're genuine. I've gone through like 3 sets of pads on the same rotors on my old w202 and never had a problem with vibration. I drove that old w202 for over 9 years.
I haven't had to change my pads or rotors on my w212 yet though so I can't speak to the quality of those.
Is your E250 a diesel? I just checked the brakes and pads on my 2011 E350 Bluetec diesel, and at 54K miles they were like new.
The diesel has so much engine braking that the brakes are only lightly used, and could be a lifetime item.
On the other hand, my SL55 at 94K has a good sized lip on the massive rotors, 5K mile pads half worn, and will likely need the grinding you mention soon. Still above minimum thickness.
The 4-cylinder has minimal braking power and now when I go back to V6 bluetec, I am annoyed with constant surge when the transmission downshifts. Does anyone know if the program can be adjusted?
Anyway, I am trying to remember and in last 25 years the only rotors I had to replace was when I bought Audi for my son.
I was doing >100k miles on old brake pads, even in Fiat and last time I check Akebonos after driving 80k on them, the pads wear was in range of 20-25%.
Only exception was ML where pads lasted 60k, but most owners report 30k.
I was referring to grinding the lip, when the rotor still has lot of thickness left. MB does not have much thickness for turning the rotors, so if you have deep groves - they call for rotor replacement.
Grinding front rotors is a breeze. When you angle grinder at good angle - the grinding will start turning the rotor for even finish. Rear is more difficult.
Thanks for the explanation. Not sure the shops will attempt that though.
Originally Posted by belarus27
If your rotors are smooth without any grooves or bad wear id keep them... otherwise replace them. I did my fronts over a month ago..and i replaced rotors and pads. But my rotors were bad.
How do you know exactly if you have grooves? I see grooves when I look at the rotors but I don't feel them when I touch them, except for the lip at the outer edge of the rotor. I attached photos of the front and rear if that helps.
This how i know.... i actually could feel them on the rotor (sorry couldnt find a pic of rotor ) and i could clearly see the same pattern on the pads (see pic)
This how i know.... i actually could feel them on the rotor (sorry couldnt find a pic of rotor ) and i could clearly see the same pattern on the pads (see pic)
Thanks. Mine must not be grooved then since I can't feel grooves with my finger pad or nail.
fisch, as others have noted, I wouldn't replace the rotors with a pad change, unless...
1) The rotors are warped and apparent in your steering while braking (wobble).
2) The rotor thickness is near the wear minimum, as measured with a micrometer.
On my previous Mercedes, I did not replace the front rotors until I installed it's second set of pads (meaning OEM + two sets of pads) around 65,000 miles. When that set of fronts wore out, (about 95,000 miles) I replaced all four sets of pads along with all four rotors (the rears needed it at that time, only).
Your mileage may vary, depending on how much city driving (constant brake applications) you do. Looking at the pics you've posted, I doubt the rotors need to be replaced at this time. In contrast, mine were deeply grooved by the time I replaecd them. And almost without exeption, the rears will wear much less quickly than the fronts.
Thanks for the explanation. Not sure the shops will attempt that though.
Why would shop want to do risky job requiring some some skills for small charge, when they can replace rotors for $500 profit and easy job?
Same is with replacing axle boots on 4Matics, what can be $100 job for DIY, or $2000 charge at dealer.
With some thinking I can come with few pages of sample like this. s
Why would shop want to do risky job requiring some some skills for small charge, when they can replace rotors for $500 profit and easy job?
Same is with replacing axle boots on 4Matics, what can be $100 job for DIY, or $2000 charge at dealer.
With some thinking I can come with few pages of sample like this. s
Reading this forum about warped front rotors on E550 vehicles I think it is more risky to change them. I would NEVER change my rotors if I did not need to. Need to is when they are warped or worn below minimum thickness.
Grooves on rotors normally do no harm at all. New pads will wear in to the grooves after some use of the brakes.
Unfortunately, I can't see the minimum thickness stamp on the rotors themselves. Perhaps you have to remove the wheel to see that or I was looking in the wrong place. At any rate, some online searching for products shows that new rotors for the E550 come with 32mm on the front and 24mm on the rear. From reading online about MB rotor thickness and some product descriptions, the service limit appears to be about 2mm (front) and 2.6mm (rear) of wear before you shouldn't use again with new pads. So the service life for the rears is longer than the fronts which get more wear naturally.
Dropped my car at the indy shop today for them to change the pads and check the rotors. They said they will measure them to check and call me about the need to replace. Before bringing the car back, the mechanic inspected the rotor condition with the wheel on. He noted that the rear rotor barely had a lip which was a good sign for reusing that rotor - measuring will backup that assumption. However, on the front rotors, while the condition looked good he said the lip was more noticeable and he showed me how it catches the end of his flashlight. He said he will check the wear on the inside of the rotor as well, but if both sides have this much lip then he expects it will measure below the service minimum.
Car was done after a few hours. As expected the rear rotors were fine and actually had 1.5mm left before the minimum thickness. I guess that's about 50% wear - not bad for 87k miles. Mechanic said they might need replacement when it's time for new pads. However, the front rotors did not meet the minimum specs so those were replaced. My car must just eat front rotors. According to my VMI, the original owner replaced the front pads and rotors at 38k miles. And here I am replacing those front rotors after 50k miles.
$484 plus tax for the front pads, rotors and sensor including labor. $182 plus tax for the rear pads, labor and sensor. $713 out the door in total. Better than the $1,600 the dealer wanted.
05-30-2018, 06:24 PM
