Brake “Hat” Heat Discoloration

[RamFan]

Good evening folks,

Two weeks and roughly 1,500 miles ago I swapped out the OE pads and rotors on the Mazda. They were replaced with Raybestos rotors and Power Stop Evolution ceramic pads.

Other than needing to be quite forceful on removal (thank you Illinois winter salt) installation was a breeze. Inspected all components and lubed up the slide pins before reinstalling the fresh rotors and pads.

Went out for bed in, per Power Stop instruction and all seemed to go accordingly. The next day I drove into town for a longer trip and it was uneventful. No squeaks, vibrations, shimy, etc. Only thing I did noticed was that the right rear corner developed a blue discoloration on the "hat" of the rotor. Obviously this is caused by heat, and occurred after a roughly 60 mile round trip. Car drove fine so I'm not thinking too much of it. A week later we took a trip down to KY/TN, I kept an eye on it but she drives fine and still that corner is the only one with the discoloration. Rotor surface itself is in great shape with no grooves or chips.

I think it's fine to just leave as is, but figured I'd post a pic and get your thoughts.

 

[Danno]

If you have an infrared heat gun, I would take heat measurements after a trip, both sides and see what kind of a difference you have.

 

[RamFan]

Originally Posted by Danno
If you have an infrared heat gun, I would take heat measurements after a trip, both sides and see what kind of a difference you have.


I really need to buy one, I constantly look but just end up not pulling the trigger.

 

[928]

Around $20- with the 20% coupon amazingly accurate- close enough to the $125- Fluke that got ripped off

https://www.harborfreight.com/121-infrared-laser-thermometer-63985.html

 

[JHZR2]

Yeah check for dragging brakes. You can usually smell them if they get too hot.

 

[Mainia]

You are worrying about nothing, that is a properly bedded brake rotor. If rotors are not blued, then I get worried. This is normal high performance car stuff, welcome to the club. Now get some good Ultra high perf tires and lowering springs and an alignment.

 

[RamFan]

Originally Posted by JHZR2
Yeah check for dragging brakes. You can usually smell them if they get too hot.


Only time any smell was noticed was during bed in, which is normal. Only thing I can think of is that the parking brake was dragging a bit on reinstall. I've read that when put into maintenance mode, electric parking brakes can sometimes drag a bit until they back off with "self calibration" of sorts.

The thermometer should be arriving today so I'll have more info at that time.

Originally Posted by 928
Around $20- with the 20% coupon amazingly accurate- close enough to the $125- Fluke that got ripped off


Thank you for the recommendation, I ended up getting
this thermometer , should be delivered today.

 

[Kira]

-58â„ to >700â„....That's some range! ...good for automotive applications

 

[RayCJ]

Those IR gun type pyrometers can give very inaccurate readings based on the reflective properties of the object being measured. Take two object of vastly different colors or surface textures, place them in a freezer or oven until both are the same temperature -then check them. Dollars to donuts you'll get very different readings often as much as 20-40%. If you read the instructions on those things, they come with instructions on how to compensate/estimate the real reading.

Don't put full faith in the values you get from them.

I've done certified heat-treating processes and those IR guns are only used for order-of-magnitude readings.

Ray

 

[RamFan]

Originally Posted by RayCJ

Those IR gun type pyrometers can give very inaccurate readings based on the reflective properties of the object being measured. Take two object of vastly different colors or surface textures, place them in a freezer or oven until both are the same temperature -then check them. Dollars to donuts you'll get very different readings often as much as 20-40%. If you read the instructions on those things, they come with instructions on how to compensate/estimate the real reading.

Don't put full faith in the values you get from them.

I've done certified heat-treating processes and those IR guns are only used for order-of-magnitude readings.

Ray



Thank you for this feedback, that's good information. For this purpose though, since I'll be comparing both sides which are equally reflective and in the same lighting conditions, it should still provide a good comparative reading.

Thermometer arrived last night so I should have readings later today.

 

[RamFan]

Just checked temps after a 6 mile drive. Everything seems normal. All four corners are within 15* of one another. Right rear read 131*, left rear read 121*, front right read 135* and front left read 123*.

Unless a problem arises, I'm keeping everything well enough alone.

 

[Danno]

Nice, and thanks for letting us know your results.

 

[Danno]

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