Brake job - Have dealer do it, find an independent shop, or do it myself?

[Hueydriver]

Got a question regarding rotors: do they warp? Reason I ask is that on the Hyundai forums there is a poster that irrevocably states that roto don’t warp just gather stuff from the pads! He is pretty adamant about his conviction!

 

[Volfy]

Is it possible for brake rotors to warp? Absolutely yes. Is it common these days? No.

Rotors really only warp due to thermal stress. Say you push your car really hard, enough for the rotors to get super hot... like glowing red hot. Then you hit a big puddle of water and splash a torrent of water onto the rotors. The parts of the rotors that got hit with cold water cools off rapidly vs. the rest of the red hot rotor. The ginormous thermal gradient - and the thermal stresses - that creates could quite possibly cause the rotor to deform. It's the same reason you don't spray cold water on a hot engine, lest you wish it to start leaking oil.

This was particularly bad back in the aftermath of the 70's Oil Crisis, when auto mfrs did everything they could to improve fuel economy. Cars were downsized and lightened as much as possible... sometimes too much so. Some of the early Japanese cars were tin cans back in the days. Brake rotors and drums were a prime candidate for shedding weight. Some rotors were so thin that just over-torqueing the wheel bolt/nuts could strain the rotors out of shape. IMO, a lot of these warped rotor stories are just residual nightmares that are remnants of the national-55mph PTSD that haunted a lot of us growing up in the 70s and 80's.

These days, cars have gotten much heavier, beefier and more robust. It's good in some ways, and bad in others. Warped rotors are by and large an issue no longer. But sometimes I do miss those 2000 lbs tin cans that we could toss around nicely with barely 100 HP.

 

[Hueydriver]

Is it possible for brake rotors to warp? Absolutely yes. Is it common these days? No.

Rotors really only warp due to thermal stress. Say you push your car really hard, enough for the rotors to get super hot... like glowing red hot. Then you hit a big puddle of water and splash a torrent of water onto the rotors. The parts of the rotors that got hit with cold water cools off rapidly vs. the rest of the red hot rotor. The ginormous thermal gradient - and the thermal stresses - that creates could quite possibly cause the rotor to deform. It's the same reason you don't spray cold water on a hot engine, lest you wish it to start leaking oil.

This was particularly bad back in the aftermath of the 70's Oil Crisis days, when auto mfrs did everything they could to improve fuel economy. Cars were downsized and lightened as much as possible... sometimes too much so. Some of the early Japanese cars were tin cans back in the days. Brake rotors and drums were a prime candidate for shedding weight. Some rotors were so thin that just over-torqueing the wheel nut bolt/nuts could strain the rotors out of shape. IMO, a lot of these warped rotor stories are just residual nightmares that are remnants the national-55mph PTSD that haunted a lot of us growing up in the 70s and 80's.

These days, cars have gotten much heavier, beefier and more robust. It's good in some ways, and bad in others. Warped rotors are by and large an issue no longer. But sometimes I do miss those 2000 lbs tin cans that we could toss around nicely with barely 100 HP.

Thanks for the great explanation!

 

[EdP]

Is it possible for brake rotors to warp? Absolutely yes. Is it common these days? No.

Rotors really only warp due to thermal stress. Say you push your car really hard, enough for the rotors to get super hot... like glowing red hot. Then you hit a big puddle of water and splash a torrent of water onto the rotors. The parts of the rotors that got hit with cold water cools off rapidly vs. the rest of the red hot rotor. The ginormous thermal gradient - and the thermal stresses - that creates could quite possibly cause the rotor to deform. It's the same reason you don't spray cold water on a hot engine, lest you wish it to start leaking oil.

Of course, metal can warp. But, can they also become coated and shudder from buildup? I've heard that a few times over the years. One way to allegedly cure it is to do a series of hard braking from 60 - 70 mph.
I'd also think the buildup would be visible and easily removed .

 

[srobak]

He is pretty adamant about his conviction!

Yeah I saw that thread - and while _technically_ he might be partially correct in that they do not warp in the full sense - from a more practical perspective he's not completely correct. Warping would technically mean the entire disc would change shape & waver. That doesn't happen vs. surface runout. The outer surfaces on both sides of the rotors will experience this due to unequal heating/cooling of the surfaces (which could be caused by a number of factors). The inner portions of the rotor - near the vents - do not run out or warp (unless you have worn your rotors dangerously thin) - and you would never be able to tell if those inner surfaces had warped without putting it on a lathe with a runout gauge. The commonized term for this surface runout however, is "warp" - and you do feel it in pedal and steering wheel under braking when it happens.

 

[joegr]

...
I'd also think the buildup would be visible and easily removed .

Not so much. Unless you have really good eyes and you consider light sanding easy. (The trick being to sand off the buildup, but not sand any of the actual disc down.) Having them turned is probably the best answer.

 

[Volfy]

Of course, metal can warp. But, can they also become coated and shudder from buildup? I've heard that a few times over the years. One way to allegedly cure it is to do a series of hard braking from 60 - 70 mph.
I'd also think the buildup would be visible and easily removed .

This is on our 2.0T Stinger, before I changed out the OEM pads. I'll let y'all be the judge as to whether it's visible.


As to trying to remove the deposits... IMO, it's a pointless exercise if you are keeping the same OEM pads. Heavy braking might smear off some of the deposits, but it's just gonna come right back and populate the rotors in short order. All you do is risk overheating the pad compound above the temp range it was intended to operate within. IIRC, there was a poster here a short while ago that did just that and ended up heat-spotting his rotors.

FWIW, I'd tried removing the deposits with a wire brush, at the time I swapped out the pads. Even with power tool, what a royal PITN!! I did one rotor and gave up. I myself am an avid DIYer, and even I have limits on what endeavors I consider worthy of spending my Saturday afternoon. This one is most definitely not worth the time, effort and French expletives. The replacement pads cleaned up the rotors in a couple of drives. So would turning the rotors, which I also did. That... is what I'd consider "easy".



I've had two cars with the same OEM pads now, and realistically for everyday driving, the deposits might be a bit annoying, but it's not that horrible. I swapped them out mostly because I was about the track the cars. For that, the OEM pad compound would be a bad fit. Then again, I would consider any ceramic compound meant primarily for street use a bad fit, if you're gonna track your car.

Brake pads are like tires. Pick the right type for the right application.

 

[TyG70-IL]

I got Brembo calipers for a Stinger off of Ebay for like $700, new rotors for the bigger brakes, new EBC greens for front and back, SS lines, and Motul 5.1 fluid for a total of like $1500 or so. Took some work, and I am old, so a bit sore, but not crazy to do

 

[orange260z]

These days, cars have gotten much heavier, beefier and more robust. It's good in some ways, and bad in others. Warped rotors are by and large an issue no longer. But sometimes I do miss those 2000 lbs tin cans that we could toss around nicely with barely 100 HP.

I'd love to get my hands on a clean, rust-free, unmolested 1990-91 Honda Civic Si hatch with a 5 speed. Loved that car, with the low cowl it was like driving a go-kart.

 

[orange260z]

I'd love to get my hands on a clean, rust-free, unmolested 1990-91 Honda Civic Si hatch with a 5 speed. Loved that car, with the low cowl it was like driving a go-kart.

By the way, that car (and all the other Hondas of that era) used to eat brake rotors for lunch - to @Volfy 's point, the were extremely thin to keep weight down but as a result had "limited" (really, "no") ability to absorb and dissipate heat.

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[Husky]

I'd love to get my hands on a clean, rust-free, unmolested 1990-91 Honda Civic Si hatch with a 5 speed. Loved that car, with the low cowl it was like driving a go-kart.

I just bought a 2010 Miata (6 speed, sport suspension, LSD) this past week. It's the heaviest of the four generations, at a whopping 2500 lbs, but I prefer the looks and the slightly roomier interior. What a blast! I'm in love with this little thing. I never got to drive an old Civic Si (although I certainly remember them when they were new) but I can understand the attraction.

 

[orange260z]

I just bought a 2010 Miata (6 speed, sport suspension, LSD) this past week. It's the heaviest of the four generations, at a whopping 2500 lbs, but I prefer the looks and the slightly roomier interior. What a blast! I'm in love with this little thing. I never got to drive an old Civic Si (although I certainly remember them when they were new) but I can understand the attraction.

Congrats, and welcome to the club!!!

I have a '99 NB1 - it's a little on the porky side for an NB1 (likely just a bit under 2300lbs), as it has pretty much every option except for the heavier 6spd manual or auto trans. My original one ('92 NA) didn't have air, and neither did the NB when I bought it, but it's too hot these days and (I'm getting too old to not be comfortable! ) so putting the AC system in was one of the first things I did after buying the car.

Mine has the factory LSD, 5spd, and I've installed Koni yellows, Tein springs, Fatcat Motorsport bump stops with all new bushings, and a set of 15x7.5" Konig Dekagrams (wider but much lighter than my stock 15s). I'm running relatively low-performance Dunlop DZ102 summer tires because I didn't want the car to be glued to the ground, I wanted a bit of predictable slide at reasonable speeds.

Despite contrary advice from the well-meaning peeps on Miata.net (who were trying to get me to buy either expensive coilovers or springs from Flyin' Miata) the combination of the Konis/Teins/FCM bumps worked out PERFECT for road use. They all told me that the Teins were too low and too soft, I'd be bottoming out all the time, etc. Well, either the FCMs blend perfectly with the spring to the point where it's completely unnoticeable, or I don't bottom out.

My son says when we drive around we both look like idiots because we have big smiles on our faces.

 

[tarhoosier]

I had nearly the same car, prior to your modifications. 99 NB, black, LSD, 5 speed, leather interior, Nardi steering wheel. Stock plus OZ wheels. Tan top. Sold it last year to a 20 year old who had plans+ and I loved his energy so much I gave him a great deal.

 

[Volfy]

Despite contrary advice from the well-meaning peeps on Miata.net (who were trying to get me to buy either expensive coilovers or springs from Flyin' Miata) the combination of the Konis/Teins/FCM bumps worked out PERFECT for road use. They all told me that the Teins were too low and too soft, I'd be bottoming out all the time, etc. Well, either the FCMs blend perfectly with the spring to the point where it's completely unnoticeable, or I don't bottom out.

There are no absolutes in suspension tuning. Only different compromises, with nuances not always appreciated or understood. What works great for one application doesn't always prove optimum for another usage case.

I'm typically a bit leery when folks ask how I set up my car, knowing what I say would invariably be taken out of context and be used in other setups that don't resemble mine. I could tag on a whole host of caveats, but folks would still pick and choose what they want to hear and whatever happens to reinforce their intent.

My son says when we drive around we both look like idiots because we have big smiles on our faces.

At the end of the day... that is all that matters.

 

[blnewto]

I'd love to get my hands on a clean, rust-free, unmolested 1990-91 Honda Civic Si hatch with a 5 speed. Loved that car, with the low cowl it was like driving a go-kart.

I'd love an unmolested Honda, but an S2k, any year is fine

 

[Volfy]

I just bought a 2010 Miata (6 speed, sport suspension, LSD) this past week. It's the heaviest of the four generations, at a whopping 2500 lbs, but I prefer the looks and the slightly roomier interior. What a blast! I'm in love with this little thing. I never got to drive an old Civic Si (although I certainly remember them when they were new) but I can understand the attraction.

Just about any vintage Miata is worth owning. Aftermarket support is phenomenal. If only G70/Stinger platform is 1/2 as well supported.

I'd love an unmolested Honda, but an S2k, any year is fine

Yes, as would just about every other JDM/KDM enthusiast.

 

[Husky]

Yeah, an S2k was my other choice, but they're harder to find and more expensive. I'd love to drive one though.
You're right about the Miata community and aftermarket support, really great!

 

[FirstTurbo]

Except, no brake system is sealed from ambient air. For a hydraulic brake system to function, it must allow for expansion/contraction of the working fluid, as well as volumetric change from worn pads. So, it is almost always vented to atmosphere. Heck, even "sealed" brand new brake fluid bottles - if left unused long enough - will eventual absorb enough moisture and darken. I've learned this the hard way and so I no longer buy brake fluid unless I'm ready to use it.

Most drivers get away with old wet brake fluid because most drivers don't really push their cars all that hard, so the brakes don't get hot enough to boil even old wet fluid with reduced boiling point. But... if you chance upon a situation where the brakes do need to work hard - like down steep long descents through mountain passes - you're taking a big risk of vapor locking your brake system, with some potentially deadly consequences. This guy was originally sentenced to 110yrs for killing 4 people when his truck's brakes failed.

Truck driver's sentence reduced from 110 years to 10 by Colorado governor in fatal crash

Gov. Jared Polis commuted Rogel Aguilera-Mederos’ sentence by 100 years, calling the 2019 accident a “tragic but unintentional act.”

www.nbcnews.com

Don't be like him.

Ya never know until ya know. Now I know. Good to know.

 

[CL65Captain]

I have never had a brake rotor warp, and that's with my NSX's fronts getting up to 1200F on the track. Crack... that's a different story. This a rear rotor on my NSX coming off the track. We "think" what happened was I drove through a puddle when exiting the track and it shock cooled it.

And pic of the car, because someone is going to ask.

 

[blnewto]

I have never had a brake rotor warp, and that's with my NSX's fronts getting up to 1200F on the track. Crack... that's a different story. This a rear rotor on my NSX coming off the track. We "think" what happened was I drove through a puddle when exiting the track and it shock cooled it.

And pic of the car, because someone is going to ask.

View attachment 62808

View attachment 62809

Nice car, you still have it?