The brake story: frequent disk warpage

[Lux]

Haven't posted in two years, but here we go:

Right off the bat, I would like to be clear that I don't slap on cheap aftermarket garbage, ever. I use only made-in-Japan, genuine Toyota parts for my Yaris. Everything is Japanese, even my air and oil filters get imported for it...

But one issue has been bothering me lately: high consumption of front brake disks to thermal warpage. I do make periodic high-speed stops (fluctuating highway driving), carry extra weight, but maintain the car meticulously. I do not race the car and absolutely everything is factory original, other than the roof rack.

My current set of genuine Toyota brake pads were installed 2013 November. Brake disks were replaced with genuine Toyota disks at that time.

Disks were warped in 2014 April. Replaced with new genuine Toyota disks.

Initial signs of disk warpage arose in late 2014 August. Not yet replaced, but it is worsening. I am still on the same set of pads. Caliper carriers and hubs checked, cleaned and greased every time.

My rear brake assemblies are completely dismantled, cleaned, sanded, lubed, reassembled, and readjusted every autumn. That is a 20'000 km interval. Retightening shoes occurs every 3 months with the wheels off. I can confidently rule out inadequate adjustment of the shoes as a factor because of this.

It appears that my combination of repeated high-speed stops, with a payload, is exceeding the service duty of the factory brake system for this market. I would like to go competitive driving with the car some day, but not with my current brake configuration. It got me thinking of a couple of potential solutions:

1. Japanese Vitz RS Rear disk conversion. Remove & replace rear axle assembly with genuine Toyota assembly from Japanese market NCP91 RS... factory-equipped with rear disk brake.
2. Front big brake kit. Higher heat capacity and improved dissipation. Would like to keep the unsprung weight down if this option is followed through with. Monobloc calipers not required but I'll consider them.
3. NCP131 (2012- ) complete brake system swap. Do they fit the NCP91? Fit within factory 15-inch wheels? Same master cylinder?
4. I don't know of any other options.

What do you guys think about this? Material quality and reliability are absolute; nothing else matters. That means no offshore (or maybe domestic) solutions. It's over $160 for a pair of disks, and I change them 2 to 3 times a year at this rate. If I allow this to persist, I will be better of throwing the money at a custom Alcon setup in a few years.

Thanks

[Exiwolfman]

Do you do the work yourself or shop also car auto or stick?
Also road conditions ,dirt roads etc I drive my car hard and may not carry a load at all times and not had any problems with rotors but I do clean and lube my caliper pins/sliders and make sure all is moving .
Need more info from you cos honestly if u are using Toyota parts one should not have ur problems unless there is an issue either with parts or ur driving style .


sent from my S4 on Mars

[Lux]

Oops! Forgot to mention those details. I do my own work, granted that I'm not busy and tired (which feels like all the time). The driveline is manual gearbox.

Overall, my driving is admittedly pretty tame. I'm talking Markham/Richmond Hill sort of driving, minus all the crashing and other stereotypical attributes for that part of Toronto.
Indeed, I always make sure my hardware is clean, free-moving, and lubricated whenever the wheels are off.
I, too, expect Japanese-made parts to be superior in quality, which is why the short service lives of the disks is bothersome.

Toyota's 1-year brake warranty is nullified if they don't install it; 90 days for over-the-counter sales if invoice is presented.

[CoryM]

Hi Lux,

It may be as simple as a minor adjustment to your driving. Think about racecars: You often see them with glowing steel rotors, yet no pulsation. If heat alone were the cause that wouldn't be the case. Where the problem comes is when they cool down. If you get the rotors hot, then stay at a complete standstill with your foot on the brake, the area underneath the pads cools down slower. This makes that area different thickness than the other areas, and the pedal pulsate. The reason you only see it after heavy braking is because you need to get the rotors up to a certain temp to affect the grain of the steel. So you need to either keep the rotors below that temp, or cool them down evenly.

Fixes:

- instead of staying on the brakes steady down a hill, release them occasionally. They will cool down a LOT in the second or two you release.
-always come nearly to a stop, and then let your car roll for the last few feet. Let the rotors cool down below the critical temp before sitting there stopped with foot on brake.
-if your rotors are hot, but you still need to hold the vehicle at the light etc, use the park brake for a few seconds. Rear brakes do not get nearly as hot as front and are much less likely to warp.
-make sure your rear brakes are adjusted correctly. Otherwise the fronts end up doing all the work.

I have never warped a rotor, and definitely not because I brake gently. I brake hard (I even drive on R-comp tires and can brake much harder then street tires), but I don't let the rotor cool down at different rates. I'm also from BC..... our hills are the size of your mountains

Cheers.

[IllusionX]

Honestly, I never had to brake hard in GTA. If I do, it's because I wasn't able to catch the next light on hwy7 or something.

I never clean or lube my caliper a and I do not have a single issue. The front brakes last about 5 years before they don't wear evenly and needs replacement. But they never warp.

[barryware]

I thought my rotors were warped until....

I used a torque wrench to properly tighten the wheels after a rotation instead of just tightening the lugs with a ratchet.. They smoothed right out.

The new parts I bought (pads, rotors, drums, shoes) are still in a box in the garage.. Never needed to replace anything.

[CoryM]

Originally Posted by barryware

I thought my rotors were warped until....

I used a torque wrench to properly tighten the wheels after a rotation instead of just tightening the lugs with a ratchet.. They smoothed right out.

The new parts I bought (pads, rotors, drums, shoes) are still in a box in the garage.. Never needed to replace anything.

Sounds like you just about had your wheel fall off. Lucky you caught that beforehand.

On that note, unevenly torqued wheels can also cause brake warping. Since the wheels clamp the rotors to the hub, uneven torque can distort the rotor. So when it gets very hot, it may cool in an abnormal shape. I used to work in a shop that used "torque sticks" and now that I am in a shop that every wheel is torqued by hand, we see much less brake pulsation issues.

Cheers.

[nortonfb]

Centrix has some interesting articles about braking.
They cover juddering and pulsing very well.
Just do a search for Centrix brakes.
Norton

[barryware]

Originally Posted by CoryM

Sounds like you just about had your wheel fall off. Lucky you caught that beforehand.

It was not lose.. Just not torqued / tightened properly ~ evenly.

[Lux]

Hi guys.

I am aware of the effects of wheel torque-- and variations thereof-- on the brake disk and hub assembly. I am fairly confident in the torquing of my own wheels (120 Nm) and the accuracy of my torque wrench, being that it was recently calibrated by NIST-traceable equipment. I checked its accuracy on the weekend against my other torque wrenches and they are all consistent: variation within 0.7% or less of each other.



My torque wrench is the Snap-on TQFR250E. My two others that I checked it against are Snap-on ATECH3FR250B and Snap-on ATECH2FR100B.

With that being said, I think we can drop the speculation of improper wheel torque.

Originally Posted by CoryM

Fixes:

- instead of staying on the brakes steady down a hill, release them occasionally. They will cool down a LOT in the second or two you release.
-always come nearly to a stop, and then let your car roll for the last few feet. Let the rotors cool down below the critical temp before sitting there stopped with foot on brake.
-if your rotors are hot, but you still need to hold the vehicle at the light etc, use the park brake for a few seconds. Rear brakes do not get nearly as hot as front and are much less likely to warp.
-make sure your rear brakes are adjusted correctly. Otherwise the fronts end up doing all the work.

Hi CoryM, I still think the disks are unable to cope with the heat and am still considering alternative solutions. Do larger brake calipers and disks from another Toyota car fit on the front? What about the rear disk conversion (using genuine Japanese OE parts)? By the way, I do make sure to bed in the brakes with a increasing-torque regimen after installing them. Additionally, after a high-speed stop, I hold the car with the parking brake in an attempt to prolong the life of the disks and avoid prolonged parking of the hot pads on the same section of disk... although that seems to have been wasted effort because they is still disk warpage.

Kindly

[WeeYari]

Originally Posted by Lux

Do larger brake calipers and disks from another Toyota car fit on the front?

http://www.yarisworld.com/forums/showthread.php?t=36955

[CoryM]

Eesh. Someone else with too much money in torque wrenches (at least mine are different sizes though :þ ).

WeeYari posted a nice link re: bigger front brakes. Re: rear brakes, unless you feel the drums are overheating and fading (causing the fronts to work harder), there is no point upgrading. See attached photo to get an idea just how little the rear brakes do (that's full braking w/ all-seasons). Just make sure the rears are always adjusted correctly. Use a little caution upgrading the fronts as bigger is not always better, and let's be honest, if you are braking hard enough to warp stock rotors you are probably going to brake harder with the larger rotors. My Mother warps rotors regularly. I have tried just about every combination of pads/rotors and even tried racing hardware at one point. End result is now I just throw the cheapest rotors in when she warps them, and use the same pads.

My suggestion to you would be to try another set of OE sized brakes, and install cooling ducts. If you can keep rotors below their critical temp, they will not warp even if you hold foot on brakes at stop etc.

I still think if I can take cars over the Coast Mtns full of camping gear and not warp, you should be able to adjust your driving to not warp brakes in flat Ontario. And I have owned cars that have undersized brakes on them from factory (the Yaris actually has pretty good brakes for what it is).
Cheers.

[Lux]

I will consider either upgrading the front brakes to Scion xD or converting the rear axle to the Japanese NCP91 unit with disk brake; quite hard to find, it seems.

The purpose of my front brake upgrade isn't sheer stopping power. Brakes are centrifugal heatsinks and the objective, here, is to improve their ability to absorb and release heat energy.

I can assure you that my driving is not an an issue being that my locale would not allow for that type of speed. I'd be lucky to reach 60 km/h, anywhere, to or from work, any time, on any day. I mentioned sudden highway stops because that is when the disk warpage is most noticeable.

Does anybody know if the NCP131 (2012- Vitz RS/Yaris SE) brake system fits on the NCP91? It could save me, and many others who are interested, the trouble of trying to source a Vitz axle assembly from overseas if our own market has them plentifully.

[enviri]

The rear axle certainly looks very similar for the ncp131 to the ncp91..the chassis mount may be slightly different though. The ncp91 complete rear disc set can be had for about 700-900USD shipped from JP (DHL). You can certainly install the whole ncp131 rear disc on your existing rear axle but a custom mount must be made for the caliper, behind the hubs. You will need ncp131 rear discs/caliper (09 corolla xrs calipers have been reported to work also..dont take my word for it) and ncp131 ebrake cable, since the ebrake is direct caliper to rotor...no drums.

[enviri]

I'm the first to have both scion xd fronts and jdm rear discs :) You have to remember that the SE/RS grade has the setup I have except my front calipers are slightly larger.

[eseibel67]

Originally Posted by CoryM

Hi Lux,

It may be as simple as a minor adjustment to your driving. Think about racecars: You often see them with glowing steel rotors, yet no pulsation. If heat alone were the cause that wouldn't be the case. Where the problem comes is when they cool down. If you get the rotors hot, then stay at a complete standstill with your foot on the brake, the area underneath the pads cools down slower. This makes that area different thickness than the other areas, and the pedal pulsate. The reason you only see it after heavy braking is because you need to get the rotors up to a certain temp to affect the grain of the steel. So you need to either keep the rotors below that temp, or cool them down evenly.

Fixes:

- instead of staying on the brakes steady down a hill, release them occasionally. They will cool down a LOT in the second or two you release.
-always come nearly to a stop, and then let your car roll for the last few feet. Let the rotors cool down below the critical temp before sitting there stopped with foot on brake.
-if your rotors are hot, but you still need to hold the vehicle at the light etc, use the park brake for a few seconds. Rear brakes do not get nearly as hot as front and are much less likely to warp.
-make sure your rear brakes are adjusted correctly. Otherwise the fronts end up doing all the work.

I have never warped a rotor, and definitely not because I brake gently. I brake hard (I even drive on R-comp tires and can brake much harder then street tires), but I don't let the rotor cool down at different rates. I'm also from BC..... our hills are the size of your mountains

Cheers.

This is great advice. I use my brakes HARD, yet I've never warped a rotor and the friction lasts a very, very long time. Proper lube and cooling are the key. The absolutely worst thing you can do is hard stop to a complete rest and then stand on the pedal against a smokin' hot rotor.

The only other thing I would add to above post is that it's a good idea to "bed in" a new set of pads. Google the procedure.

[Lux]

Originally Posted by enviri

The rear axle certainly looks very similar for the ncp131 to the ncp91..the chassis mount may be slightly different though. The ncp91 complete rear disc set can be had for about 700-900USD shipped from JP (DHL). You can certainly install the whole ncp131 rear disc on your existing rear axle but a custom mount must be made for the caliper, behind the hubs. You will need ncp131 rear discs/caliper (09 corolla xrs calipers have been reported to work also..dont take my word for it) and ncp131 ebrake cable, since the ebrake is direct caliper to rotor...no drums.

Mate, THIS is the raw technical information that I was looking for... no drivel about wheel torque or braking technique. Thank you so much for this. A diamond geezer, you are, truly.

Indeed, the mounting location for the rear calipers are different for our drum-type axle, which is why I'm inclined to swap the complete axle assembly-- for direct fit and OEM quality. Going back to my first post: "quality and reliability are absolute; nothing else matters."

Would you reckon anybody here would know the technical details regarding NCP91 vs. NCP131 torsion beam axle mount geometry? I personally don't suspect them being different, but anything could have changed year-over-year thanks to NCAP and NHTSA. Also, where did you find your NCP91 rear axle?

I reckon that your current brake configuration is the dog's bollocks; quite impressive. Do you have pictures? How is the stopping power and bite consistency after abuse?

[CoryM]

Originally Posted by Lux

no drivel about wheel torque or braking technique.

Wow.... very classy. Keep in mind that you posted here asking questions and looking for help. Maybe next time you post, let people know beforehand that if they don't tell you what you want to hear, you aren't interested. It will probably save you from having to read such drivel again.

Loaded or not, the Yaris does not have inherent issues with brake warping. Yet if I want to, I can easily warp them in less than 15min by lousy "driving technique" (I've done it before). Simply put: It is most likely that your "driving technique" is the cause. Just because your ego doesn't like it, doesn't make it false.