Brake Rotor Surfacing?

scruffydog

I have about ~24K miles on my 370z Sports Touring and I tracked my car twice since I had it. On second par of tires, still have quite a bit of meat on the first pair of Nismo Brake pads.

I'm curious if I should take my rotors in for surfacing. I noticed it's actually warped (when I spun it around the wheel hub, I noticed it doesn't spin evenly, but I don't notice any vibration issues when I drove my car. I did some research online and there's kind of a mix feedback. People are saying it's enough drawback from taking away material that could help it cool. Also it'll reduce the life of the rotors by quite a bit. (which i don't really mind as much if the tradeoff is for a good cause). I'm going to track this car in July and I'm trying to prep it the best I can without replacing the rotors.

I intend to switch the Rotors out to Slotted/Cross drilled (possibly 2 piece one day)

Any advice? Should I do it? I already have the rotors off as I'm putting in a brake cooling duct kit.

Cheers.

bvl

I doubt they are truly warped. People incorrectly toss that word around.

The vibration could be a number of things but often its just deposits that build on the surface over time. I see this a lot as I am not easy on the brakes but I try to remember every now and then to really warm them up through a few hard stops. This gets them to temp to scrape off the material *if* the build up is not bad. If its bad, turning the rotors a few thousands of an inch will scrape it off.

Find a safe place and do a series of accelerations and full on hard stops starting at 40mph and building to 60. 8-10 cycles should be good.

This has worked a few times for me. The only time I have truly needed to replace rotors is when I wore them over 50K+ miles and very hard brake pads (Hawk HPs) and they were less then the specified minimum thickness.

Stoptech has a few good articles on this, check them out.

- b

ps: adorable pup...what breed?

scruffydog

Thank you very much for such a detail explanation and help! Much appreciated.

I know whatcha mean when you hear a lot of people randomly toss that word warp freely when they experience vibration when it could be from a result of many things not related to the rotors. I actually don't have any vibrations issues or at least not able to experience any myself. But as I am putting a cooling duct into my 370z, I noticed the Rotor isn't spun evenly when I rotate the rotor around the hub. That could be just me though as I'm just eye balling for lateral runout (cross section of the rotor) as I spun it around.

I stopped by a Pepboyz place and asked one of the techs and he said that surfacing is only going to be good for rotor scoring but if the rotor is warped, they don't surface it as I just need to replace it.

In the end, I think I'm just gonna leave it as is and perform the brake tests you suggested! Great tip.

I also stumbled upon a decent short article what trade offs I'll have if I surface it.

"When you have your brakes serviced, it is always verified that your rotors are not warped. They must meet a certain standard for thickness. Rotors can then be taken and placed on a lathe. They are sanded on both sides to provide a smooth finish. This is the correct procedure for rotors that need to be resurfaced. It gives a good working service for new pads. The problem with this is that by resurfacing all rotors that meet requirements, people lose precious rotor surface. Rotors naturally become smooth with use.

People are losing rotor life because otherwise good rotors are being resurfaced too frequently. The more modern rotors are thinner than those of their older counterparts. As a rotor thins, it has less ability to dissipate heat. This will eventually cause warp, so keeping rotors sturdy is vital.

There are now many manufacturers that stand behind the fact that their vehicle rotors do not needs to be resurfaced during pad replacement. Ford and General Motors both now recommend reusing rotors as they are as long as they meet the thickness requirement.

There are rotors that still need to be resurfaced. These include rotors that are warped, scored, or not up to thickness standard. Another reason a good rotor may need to be resurfaced, is if you must have its partner on the same axle surfaced. They need to be equaled out to prevent pulling."

LINK TO ARTICLE

PS> I have a yorkie, actually I have 2 yorkies and 1 Maltese...but of bratty doggies.

bvl

aha...I was right (wife and I were trying to figure the puppy pic out. We have a pom and a pom/poodle/possibly maltese mutt). Back to cars...

Rotors are a bit thinner then past years sure, but without a micrometer its hard to accurately assess the run out. A true warping (where the iron of the rotor is no longer parallel in regards to the brake pad surface) would be extremely obvious with high rotational speeds when braking. This is why I quietly raise the BS flag when a few general techs in the past have said 'your rotors are out of spec' but they never put the measured diameter nor the limit (from the factory service manual) on the work order.

PA state inspection centers are notorious for trying to suggest work every year. I hate this state's DMV....

You will see many debates about new brake pads must have a turned rotor (clean surface) vs. the exact opposite. Its kind of like oil type discussions, there is no clear right way.

Having done it both ways in the past, and previously tracked a few cars my personal experience its to continue with Stoptech's style of advice and be sure to get the rotors up to temp to scrub off crap. I have no issues putting new pads on existing unturned rotors. I just break them in immediately with 8-10 hard stops from 40-60 MPH and enjoy the lovely smell.

This is not as necessary with more aggressive compounds I have used. But those compounds also tend to wear more metal from the rotors (as seen by wear over 40-50K miles of use. I recently used Hawk HP (instead of HPS) and while they stopped great, they wore brembo replacement rotors far quicker then other pads I had used on the WRX).

Low noise low dust pads tend to be more organic based and in my experience easier to leave deposits. I don't have enough miles on the Z to see how these pads are. Whatever they are, they are going back on the car when they wear out: very happy with feel.

- b

Tinman

I work at an autoshop with the name called Brake Specialists Plus. Once my own pads on my Z are at discard, I'm replacing the rotors. I drive my car hard and brake hard. Keep in mind that rotors are relatively cheap if they are stock OEM. They're only about $80-120 each wherever you buy them from. My rule is that if one of my customers bring in slotted rotors to machine/cut, I won't lathe them. I wouldn't want to waste their time or mine. Now for other "passenger" cars, I measure out the rotors and determine if they can be cut or discarded. Alot of European cars require replacement of pads AND rotors during a brake job.

HKYStormFront

i used to work at a dealership as a tech and a service writer. from that standpoint i would tell you that you can resurface them but your best option is to replace them, honestly. if you are planning on tracking the car, why risk it? at best the rotors will overheat quickly (or at least quicker than before) and you'll have to pull off and wait for them to cool. if they don't cool evenly, they'll most likely warp and need to be replaced anyway. i'd just save pennies till you can get these:

DBA 370Z/G37 2-Piece Slotted Front Rotors

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ykalinin

Just had mine replaced under warranty @ 15K miles. I believe they are technically considered a non-wear item and so no reason why you should get them replaced or in the very least cut.

cossie1600

I don't know why you want to waste your time and money playing with the rotor. If they are not causing vibration and there is no noticeable lip on the edge or cracking. Keep it until they get really bad.

scruffydog

cheers, thanks for the reply. I didn't surface my rotors and I don't any vibration anymore.

Dan@RAD

Completely agree with this. Why run the risk of brake components failing especially if you track the car? Possibly against what these articles say, on track cars or even occasional track cars, we still stick by the old rule of thumb to replace the rotors with each set of pads. Definitely save for a set of 2 pieces to save some money in the long run.

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DEpointfive0

Resurfacing will only help if your rotors are scored, if they're truly warped all that will happen is you'll pay money and as soon as the discs warm up they'll warp again almost immediately because you'll have thin and thick areas due to the previous warping

DEpointfive0

I have also heard that you don't need to resurface them every time you swap pads... On my other cars I usually do resurface, didn't one time... On the Z I plan to get drilled or slotted once my pads run thin