Got new pads—should I machine, replace or leave rotors as is?

[Ales]

I have an 06 a4 with 46,000 miles or so and needed new pads. I bought Hawk HPS pads so far that are not mounted yet and read that I should have rotors machined or get new rotors, even thought I was told my disks were still ok. Should I just have them all (front and rear) replaced? Should I buy new fronts and just machine rears? What do you guys suggest? I don't do any hard driving or anything, just normal driving and not looking for any performance type of stuff.

And what do you think of ATE for just standard blank rotors?

And how much does it usually cost to machine rotors btw? I've seen ATE rotors for $150 set for front and $100 or so a set for back. So depending on cost to machine rotors, should I just buy all new rotors?

Thanks for all the help.

(BTW, yes I posted this in the Brakes section but there is not much action going on in there.)

[pnoyworx]

You should always resurface when changing pads so the seating matches. Resurfacing is pretty cheap, I think 20bux is pretty common price.

[Übermensch]

You should always resurface when changing pads so the seating matches. Resurfacing is pretty cheap, I think 20bux is pretty common price.

x2

[Ales]

Thanks guys, sounds like I will just be resurfacing them for now.

[elwigglero]

replace. I went with Adams Rotors. Price and quality is good.

[Ales]

Thanks, would be nice but they are little pricey for what I was looking to spend on this, if I even have to buy new rotors. Looks like I may just be machining my rotors.

[B7Daily]

I have always replaces pads and rotors when doing the break i don't know why most likely I'm tough on breaks. I like to break deep in the corners but i don't really drive like i use to but i have replaced the breaks at about 40k and i have to do them again and im thinking about upgrading to BBK for all 4

[LampyB]

both VW + Audi won't ever resurface rotors, they require replacements with every pad change. every aftermarket shop in town here won't resurface either. problem is you reduce the thickness of the rotor thus reducing heat dissipation and basically reduce the effectiveness of the rotors. ECS has pretty solid deals on rotors right now, and shipping is only about $20 for the whole set (even though they're heavy as hell). dbctuning.com often has great deals, and so does mjmautohaus.com.

there are huge discussions on this, but in consideration of the fact that even the majority of aftermarket shops tell you its necessary to replace rotors with pads i'd do it...you own a high end german car, not a toyota or some cheap commuter car.

[pnoyworx]

I'm sorry guys. But those that think you HAVE to replace your rotors while being within your limits of thickness have fallen for a sales gimmick. Many of you may have the money too fall for those types of sales trick, but for those that don't have the money, resurfacing is sufficient, safe, and economical. If you commute your car, have a little spirited drives, you car will stop. Whats important is you check your brake fluids, keep them fresh, especially if your from cold, wet areas. - Heck a local Lotus and Porsche race shop resurfaces slotted and drilled race calipers. No need to throw away a good thing if it still works and is within the industry limits.

I would get a few recommendation from around you area. What might be a trend for the South, could be different trend to do up North.

[DrivTech]

If you have the extra money to spend - replace them. If you don't - resurface them. Regardless, you should do one or the other. There are many benefits to having a perfect surface for your new pads. - longer life, etc. And, make sure you don't cheap out on parts that are vital towards the overall function of your vehicle (brakes, suspension, etc.)

[Der Konig]

I say replace, resurfacing rotors is highly unrecommended. Sell the car if you can't keep up with the proper maintenance on it and buy something that you can. Resurfaced rotors will end up reducing pad life ending in more frequent replacements and more labor/cost. If you are going to do something do it right. Rotors aren't that pricey.

[pnoyworx]

Lol. Snicker.

[elwigglero]

Lol. Snicker.

Did you really Laugh out Loud and then snicker? Seems weird.

Rotors can be machined without any 'noticeable' decrease in performance (as long as they're within factory specs), but many shops don't bother using a micrometer to measure the rotor's thickness and just eyeball it. Because of the inconsistency of a lot of independent shops and the refusal of anyone affiliated with Audi to machine rotors, it's generally a better idea to replace rotors along with pads. It's really not that expensive and is only necessary every 30k miles or so.

[pnoyworx]

a laugh with a snort... ehehe

[brownishwater]

I get new rotors every time I replace the pads. Adam's rotors FTW!

Beats the shit out of what brake shops are going to charge you for all 4 rotors.

[Ales]

Yea, I have no problem buying new rotors, just wasn't sure if it was that necessary. But I won't be getting any fancy drilled/slotte rottors or anything, replacement blanks are fine. Either Zimmerman or ATE, etc.

Thanks for the info

[shaggenwagon]

both vw and audi say replace, that is how they designed them. but if you dont have the money and you want to refinish, make shure they are no more then .060 inch thiner then oem thickness. if they machine them more then that its a federal affence! even if your brakes work during day to day driving they might not work when you need them the most, to prevent a crash.

[Ales]

I'm just gonna get new rotors. Thanks fellas for the help.

[Jer]

I'm just gonna get new rotors. Thanks fellas for the help.

Send me yours then. I can't believe people just throw away good parts because of something someone said on an internet forum.

People have been turning rotors since they started replacing drums on motor vehicles. It's simple; you have them turned & then measure thickness. If they pass you're fine. Good to go for about ten bucks a rotor. That federal mandate minimum thickness isn't even close to dangerous & is more than safe. We're talking about cast iron rotors here folks. Audi doesn't do anything unique that makes them disposable. If you don't turn/measure you're likely throwing away money. Anyone who actually knows cars will agree.

[pnoyworx]

Send me yours then. I can't believe people just throw away good parts because of something someone said on an internet forum.

People have been turning rotors since they started replacing drums on motor vehicles. It's simple; you have them turned & then measure thickness. If they pass you're fine. Good to go for about ten bucks a rotor. That federal mandate minimum thickness isn't even close to dangerous & is more than safe. We're talking about cast iron rotors here folks. Audi doesn't do anything unique that makes them disposable. If you don't turn/measure you're likely throwing away money. Anyone who actually knows cars will agree.

I agree! - maybe they have disposable money too?

[80sGuy]

I have been replacing new rotors on EVERY OTHER pad changes for all my cars. I used to work for a BMW dealer and had a 325i convertible (yeah that was a while ago). My mechanics told me that the rotors can be turned at least once or maybe twice in their lifetime depending on how the car was driven, but recommended replacement was every other pad changes. For the rear pads, I also replace them every other time when I do the fronts and shouldn't have to worry about the rear rotors for a long time. Been doing this for about two decades and I haven't noticed any differences, of course my Audi has only 20,080 miles as we speak, might have to do the front pads but I'm keeping the rotors. Different strokes for different folks a I guess.

[Kim]

There are too many people who don't know enough about their cars and yet pretend to do so. Rotors wear out longer than pads. If they're still within the normal operating thickness then why is there a need to change them? You will probably need to change them every 2 or 3 pads and not less.

Please do your research.

[EErie B6]

while resurfacing or machining is optimal, you do not HAVE to do it. The important thing is to "break the glaze" on the rotor by removing the glossy shine. for this all you need is some 60 grit sand paper and preferably a random orbit or pneumatic sander. You can also do it by hand with a block if you don't have either of those. Try to sand/scuff evenly all the way around and also try not to sand in the direction the pad slides (this is why a power sander is better.)

I did this just to keep me safe and legal b/c i was not ready to drop the coin on a BBK yet... works great and the car stops just as shitty as it did new. lol. but thats because i have OEM B6 brakes, not from the brake job.

also, be sure to bleed new fluid through out the whole system... that makes a noticeable difference in brake performance too.

[Hammer]

I'm sorry guys. But those that think you HAVE to replace your rotors while being within your limits of thickness have fallen for a sales gimmick. Many of you may have the money too fall for those types of sales trick, but for those that don't have the money, resurfacing is sufficient, safe, and economical. If you commute your car, have a little spirited drives, you car will stop. Whats important is you check your brake fluids, keep them fresh, especially if your from cold, wet areas. - Heck a local Lotus and Porsche race shop resurfaces slotted and drilled race calipers. No need to throw away a good thing if it still works and is within the industry limits.

I would get a few recommendation from around you area. What might be a trend for the South, could be different trend to do up North.

Agreed.

[A4Ferrari]

why even turn rotors? just throw the pads and go ... Unless you are going to replace the rotors entirely dont touch them. I have worked at many high end dealers and its either you just throw the pads and go OR replace everything and go.... Just my 2 cents

[freaksavior]

why even turn rotors? just throw the pads and go ... Unless you are going to replace the rotors entirely dont touch them. I have worked at many high end dealers and its either you just throw the pads and go OR replace everything and go.... Just my 2 cents

I'm not an expert in the least for cars, but even I know this doesn't sound right...

[A4Ferrari]

If you go to a dealer and you need pads - They are not going to turn your rotors b/c the manuf does not recommend it. If the rotors are above spec they are good to go. The tech does not get paid to sit there and sand down the glaze on your rotor. Now if you go to a pep boys or something like that they might very well turn rotors. Here is a good example - What if you have cross drilled rotors? or For instance Stasis BBK ... You cant turn those rotors and even they recommend just change the pads and go

[Jay-Bee]

why even turn rotors? just throw the pads and go ... Unless you are going to replace the rotors entirely dont touch them. I have worked at many high end dealers and its either you just throw the pads and go OR replace everything and go.... Just my 2 cents

And this right here is why I have never had a vehicle serviced by a dealership, unless it's a recall or TSB, rotors could be glazed over and will ruin the pads within 10K.

I've turned VW rotors before, just like any other car... thickness always within spec. Does the machine shop ask you what vehicle they came off? Oh it's an audi/vw, noooo that's not allowed, we can't do it... come on.

[A4Ferrari]

Ruin pads within 10k? The only cause of that would be the driving style or pad material - Pads last!!


Thats also why if you have a brake failure you will have to pay for it because the dealership wont take responsibilty for outside repairs

[JPT]

There are a lot of places that just swap pads. On my jeep I used to swap pads only every other time, then on the other times, I would replace the discs... Never had an issue, and had to stop 35" mud tires on stock brakes (I would eventually stop LOL)...

[minameismud]

ok, since this is a brakes thread, a question: i'm at 57k and still on my factory brakes. when i ask the stealership and an independent shop how many miles i've got left on the pads, they both say "a lot", followed by a general statement about lasting until about 80k. but elwigglero above says every 30k. i've noticed no decrease in braking ability. should i do anything now?

[b7kevin]

ok, since this is a brakes thread, a question: i'm at 57k and still on my factory brakes. when i ask the stealership and an independent shop how many miles i've got left on the pads, they both say "a lot", followed by a general statement about lasting until about 80k. but elwigglero above says every 30k. i've noticed no decrease in braking ability. should i do anything now?

In short, don't do a thing. Breaks have built in wear sensors that tell you when they are dead prior to being dead. If they aren't squealing either your in the clear.

[usedtobefast]

I disagree with almost all of you and I have been working on cars since before most of you were born (51 years), not to mention doing all the mods and upkeep on the Porsche 911s I raced for 18 years.

But rather than believe me without question, let me tell you that the FACTORY manual for aircooled Porsche 911s specifically says not to turn rotors unless warped or worn with sharp edges. Rounded wear is fine. Replacing rotors depends on thickness (ie do they have enough thickness to last thru another set of pads) or if the rotors might need turning (warped or sharp edges).

Some cars are exceptions, some Ford SUVs I used for support vehicles had poor metalurgy and would rewarp quickly after turning (for warps), so I learned to replace at every change because they always warped. Early GTIs wore their rotors so fast that they were too thin at every pad change to make it thru another set.

On my Audi B7, I replaced brake pads at 35k without turning or replacing pads. No problem, there was plenty of meat on the rotors to last another round of pads. A friend of mine who has two S4s currently and goes back 25 years with Audis (also has a GT3 and I was his first driving instructor at PCA), does the same and has for many years.

Those who say that thicker rotors are better are correct, but the difference is insignificant on a street car. Unless below spec in thickness, I don't think you could measure the difference on a race track under controlled conditions. I know, I've done it.

Even if you drive very, very hard, you can never approach the demands that racing puts on brakes.

[blkb707]

Approaching 50K soon and delearship says to change only the pads on my next maintenance visit if the warning light comes on, discs change not necessary. SO i guess some dealerships are still not in the business of ripping you off just because you drive an audi. As many here say, why throw away something that is still good unless it is not hard earned money like for most of us! As the saying goes: If it ain't broken, don't change it!

[swoardrider]

My 2 cents,

Rotors need to be changed when any or all of the following occur - Deep scoring of rotor surface; any form of warping; less than half of their minimum thickness

Rotors can be turned if they are thick enough, and should be turned if - light scoring of rotor surface; changing brake pad manufacturers/compounds (don't mix compounds, unless approved by pad manufacturers!). Note: Never turn a warped rotor, the metal has already overheated, and will just warp easier, being thinner. Do not turn cross drilled rotors, most have the holes stress relief chamfered to minimize cracking. Turning them can cause them to crack prematurely. Also ruins the machine's cutting bits

Rotors can be re-used if - new pads are same as old pads, and there is enough rotor thickness (this is why the stealership either changes just the old OEM to new OEM pads, or replaces rotors and pads)

This has been my experience from multiple street, race, and off-road vehicles over the past 20 years.

[elwigglero]

ok, since this is a brakes thread, a question: i'm at 57k and still on my factory brakes. when i ask the stealership and an independent shop how many miles i've got left on the pads, they both say "a lot", followed by a general statement about lasting until about 80k. but elwigglero above says every 30k. i've noticed no decrease in braking ability. should i do anything now?

depends entirely on the pads you're running and your driving style. Noone can really guess how long your brakes will last. Take a look at new pads when you buy them and then take another look in 10,000 miles or so to get an idea of your amount of wear. More aggressive pads will wear considerably faster than oem.

[JPT]

...More aggressive pads will wear considerably faster than oem.

x2. And will wear the disc faster too...

[jriddle11]

I almost always do pads and rotors at the same time.

[Hammer]

I disagree with almost all of you and I have been working on cars since before most of you were born (51 years), not to mention doing all the mods and upkeep on the Porsche 911s I raced for 18 years.

But rather than believe me without question, let me tell you that the FACTORY manual for aircooled Porsche 911s specifically says not to turn rotors unless warped or worn with sharp edges. Rounded wear is fine. Replacing rotors depends on thickness (ie do they have enough thickness to last thru another set of pads) or if the rotors might need turning (warped or sharp edges).

Some cars are exceptions, some Ford SUVs I used for support vehicles had poor metalurgy and would rewarp quickly after turning (for warps), so I learned to replace at every change because they always warped. Early GTIs wore their rotors so fast that they were too thin at every pad change to make it thru another set.

On my Audi B7, I replaced brake pads at 35k without turning or replacing pads. No problem, there was plenty of meat on the rotors to last another round of pads. A friend of mine who has two S4s currently and goes back 25 years with Audis (also has a GT3 and I was his first driving instructor at PCA), does the same and has for many years.

Those who say that thicker rotors are better are correct, but the difference is insignificant on a street car. Unless below spec in thickness, I don't think you could measure the difference on a race track under controlled conditions. I know, I've done it.

Even if you drive very, very hard, you can never approach the demands that racing puts on brakes.

Best post in the thread. Thank you for sharing your experience in the matter.

[shiro1745]

I'm sorry guys. But those that think you HAVE to replace your rotors while being within your limits of thickness have fallen for a sales gimmick. Many of you may have the money too fall for those types of sales trick, but for those that don't have the money, resurfacing is sufficient, safe, and economical. If you commute your car, have a little spirited drives, you car will stop. Whats important is you check your brake fluids, keep them fresh, especially if your from cold, wet areas. - Heck a local Lotus and Porsche race shop resurfaces slotted and drilled race calipers. No need to throw away a good thing if it still works and is within the industry limits.

I would get a few recommendation from around you area. What might be a trend for the South, could be different trend to do up North.

Could not agree more. I feel sorry i changed mine, the originals could have done better than what i have now with a resurfacing.

[blmlozz]

Did you really Laugh out Loud and then snicker? Seems weird.

Rotors can be machined without any 'noticeable' decrease in performance (as long as they're within factory specs), but many shops don't bother using a micrometer to measure the rotor's thickness and just eyeball it. Because of the inconsistency of a lot of independent shops and the refusal of anyone affiliated with Audi to machine rotors, it's generally a better idea to replace rotors along with pads. It's really not that expensive and is only necessary every 30k miles or so.
they don't bother because 90% of rotors made within the last 3 decades have wear indicators built in. If it's @ or past the notch on the rotor, it's time to replace. If you still have 1-1.5CM of material left, you're safe.

I'm in agreement with resurfacing, but only as long as the rotor is not warped. I haven't come across a warped rotor yet where even after resurfacing it 'wobbles' right down to the veins.