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Replace Rotors when Replacing Pads

10K views 28 replies 10 participants last post by  jimvw57 
#1 ·
Hi guys,

In the next couple days, I'm about to change the front pads on my 2009 Passion and with @jetfuel and @albertlastsmart recommendation, I have purchased the Brakebest C1252 Ceramic pads. Thanks again, guys! Now, I was given a number of a mechanic from a colleague and said this mechanic would give me a good price... and actually he gave me an excellent price. Now, I know that the rotors are in very good condition. My brakes don't grind or any of the familiar noises but I did asked this mechanic that there's a slight chance, the rotors may need resurfacing. He said that with Smart cars, it is best to replace the rotors altogether rather than have them resurfaced. I asked him why and he replied, on cars like the Smart, it's just better to replace the pads and rotors all at once.

Does this make any sense to any of you and also, if the rotors are actually in very good condition, is it even necessary to have them resurfaced? I've been getting mixed answers.

Thanks!
 
#7 ·
Sometimes the rotors will develop a warp from getting hot, then cooling or water from puddles, etc so when you put new pads in, they will give you a pulsating pedal when you hit the brakes. Not a problem or affect the working of the brakes, but it can be a bit annoying. That is why they 'turn the rotors' or take a layer off them, and to eliminate any hard spots on the rotors. Most of the time they are fine when you replace the pads (unless they are worn and grinding or squealing) The price on replacement rotors is very close to the price of having them 'turned' and if they are resurfaced below the min thickness, they would need to be replaced anyhow.

Just as easy to replace them. If you are doing them yourself and want to just replace the pads, I'd go for it. Ceramic pads will tend to do some resurfacing themselves so next time you put new pads in, they may be below the limit I usually replace rotors every other brake replacement.

Hope that helps.
 
#8 ·
@jzchen I appreciate the info on rotor mm thickness. As far as pads go, I already purchased the Brakebest C1252 Ceramic. A couple good gents on this site recommended them to me in another post but I will look into them next time the pads need replacing.

@jimvw57 Excellent advice. I won't be replacing the pads myself but I'm getting a sense of what I should be looking for. Yes, this does help quite a bit too.

Thank you both!
 
#9 ·
Rotors get replaced when they are below the minimum spec or when they are warped or have obvious damage from being overheated. No need to change them with every pad change. As for turning the rotors, that is typically not recommended with Mercedes rotors because there just isn't enough meat on them to warrant that. Not sure if the Smart has the same recommendation, but I would think it does.

Len
2014 EV
 
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#10 ·
Just to add something, in your case I don't think it's going to factor in but up here with salt on the roads rotors can rust out faster then they wear out. What I mean by this is on our winter beaters I can go through a set of rotors every year as the salt corrodes the rotors. Now there is something to consider here, I can buy cheap made in China rotors for our Saturns and these rust out a lot faster then slightly more premium 'coated' rotors. Granted you would suspect that as you drive you wear the coatings off so not sure about that logic though where the rotors tend to rot out is in other areas besides the surface.

So might depend on other factors plus the 'quality' of the rotors.

Up here I can pick up Brembo rotors and pads cheaper then autostore parts which somehow didn't make sense but what the heck it was a better deal then Wagner, we don't have Brakebest parts but just checked O'rielly (we don't have them here) and my Brembo's in Canadian $$ are $58.20 CDN. I bought two sets of pads and a set of rotors the other day and just put them in inventory for when I do need to do a brake job. I'll do it myself though as it is not complicated and I'm used to doing brakes on our other cars and trucks.
 
#11 ·
Just to clarify, my '04 Sienna had a steering wheel vibration issue and it ate through one inboard rear pad. I took the pads back to AutoZone well knowing that eating through one pad is not the fault of the pads. I gave them to the counter person and he noted it's a problem with the caliper, then went to get me a replacement set without trying to charge me. I then decided I would pay the difference for their highest level pads to give them some money. I won't buy anything lower than their Duralast Gold now....
 
#12 ·
@sokoloff So I'm assuming this is what the mechanic was referring too. I'll look into this too.
@Niteshooter I live in California now but born and raised in Montreal and I remember the hard winters. Salt use to chew up everything and had to change rotors often, because of the rust. Time for me to look into a couple "how to" videos.
@jzchen This is good to know.


Thank you all and I really appreciate the feedback.
 
#13 ·
If the rotors are worn evenly, not scored and not below the minimum thickness specification they can be reused. I would rough them up some with sandpaper just enough to break the smooth glaze so they will bed-in with the pads more quickly. If the rotors are not serviceable they should be replaced. No point in trying to resurface them as they will be too thin when you are done.
 
#18 ·
Raybestos has been around for a long time. I don't know that I would call their products cheap or junk, or if they are made in China and classified as junk. I would be suspicious if the rotor had a manufacturer name that was unheard of. but I don't believe Raybestos falls in that category. The key would be if they have a warranty that goes with the price point. For that matter, putting cross drilled rotors on a smart is a bit over the top too. They are usually used for extreme applications such as racing, or heavy hauling.

ceramic pads are in the same category, but they do not emit as much dust and do work on a smart for that reason. The ceramic will wear down the rotor as the pads are used up so I would replace the rotors with every ceramic pad change. But again, that would be my choice.
 
#19 ·
I would also add that just because something is made in China, that doesn't mean it's poor quality. We should have learned our lesson from thinking products from Japan to be poor quality in the 70s and with South Korea in the early 2000s. Now Toyota is a household name and Kia is hitting home run after home run! :D

Anyway, on topic. I'm a cheapskate with some things, and I took the risk with my brakes back in 2015. At 70k (give or take) my factory pads were shot. Money was tight at the time and I replaced them with the cheapest rotors and the cheapest ceramic pads from RockAuto.

Almost 60k later, the pads are needing to be replaced. They performed well! Always quiet, no dust, always stopped the car fast. On the other hand, the rotors are rusting out. As of right now, the rust is creeping onto the braking surface. Also, they are warped too. I noticed it basically happened after a super hard emergency stop 15k ago. I mean, we're talking stopping so hard I left dark tyre marks on the pavement. I'm not sure the factory rotors would have survived that without some warping either.

Still, not bad for an out the door cost of like $40-ish back then. This time I'm getting better rotors.
 
#23 ·
Indeed, that's how it works with the 453. Surface rust gets scrubbed off in the first couple stops. The factory rotors are good at not actually rusting.

However, the rotors on the 451 are rusting inside out. So when the brake pad scrubs off the rust it just reveals more rust. I'm guessing the rotors I bought in 2015 weren't exactly made to be dressed up in salt for half the year. :D
 
#22 ·
I don't totally disagree with you about the Chinese junk. (I hate all the made in China stuff too) The op does not say how many miles are on the rotors. It's an 09 and on average should have around 80k-90k. I would definitely not just swap out the pads and reuse the old rotors with that kind of miles. I would have no problem with Rabestos rotors if that's all I wanted or could afford to spend. In the end do what the mechanic suggests and buy the best rotors you can afford.
 
#24 · (Edited)
I purchased the car back in 2013 which only had 17k miles and in the last 3 1/2 years, I only added another 8k miles so the car roughly has over 25k miles. So I did replace my pads (the original pads were very much worn out but never damaged the rotors) and when the mechanic had a look at the rotors, he said they were in great condition and could go another round with the new pads... So.. happy camper I am :)
 
#25 ·
The minimum spec on pads is usually 2 mm. Not sure if the Smart has brake wear indicators or not. Never had reason to look and never heard them being mentioned on this forum, so my guess is they don't exist. You made me look at the EPC and there is no listing for the brake pad wear indicator. Thanks for making me look. :)

Len
2014 EV
 
#27 ·
The factory pads do have wear indicators. Though, they are pretty weak. My wear indicators ripped off a month before I changed the pads...they weren't even super worn! :)
 
#28 ·
Okay, maybe I was not clear. What I meant was that there don't seem to be electrical warnings, i.e. a dash warning light illuminates, when the brake pad is low like there are on other Mercedes. When you are saying that pads have wear indicators, are you saying that there is an audible warning when the pad gets low and the wear indicator makes a noise when it contacts the rotor?

Pagid - good pads BTW, OE on many European cars.

Len
2014 EV
 
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