Infrared Images of Brake Failure

[Phasewest]

Hey Everyone, it's been a while since I posted but I thought I'd share some findings.

Recently, through the winter I had noticed what seemed like a minor dragging somewhere in the driveline, but couldn't quite pin anything down. I checked tire pressures, and discovered they were low, so naturally filled to required pressure. This seemed to improve things, but I still noticed that the car felt like something was sticking, especially when I came to a stop, and let the car coast the last little bit.

Today, I decided that when I got home from work this morning that I'd take some IR pictures (I've been trained in this at work for electrical troubleshooting) to see if there was something that could be noticed and this is what I found...

Front Left


Front Right


Rear Left


Rear Right


Pretty sure I've got to replace another front caliper as I think the Front Right isn't retracting properly when I release the brake. If anyone is interested, the part is equivalent to a 2002 Forrester, but only the piston end, the bracket has to be salvaged from the original.

Any other thoughts?

[jdmvip]

Nice work how much does this IR camera cost? I had the same issue with my front right on Impreza.

[Phasewest]

You can get a nice IR camera for less than $1000 these days. Much less if you look around. I don't know what the Canadian Tire version is like. But I think you can get it for less than $500.

I use a Fluke VT02 for most of my IR stuff. Pretty sure it set me back about $1000 when I bought it, but that was a few years ago now.

But at work we use mostly FLIR and Micron. Those can get very expensive.

Now, if only I could figure out what the misfire is when the motor is cold...

[Vancouver98STi]

You can get a nice IR camera for less than $1000 these days.

Those are great images, and quite helpful... but for now I'll continue to use the back of my knuckle.

[jdmvip]

Do you guys think those Digital Temperature gauges would work as well? This reminds me of the less scientific version but when I had a rear right wheel bearing go on Impreza I could physically feel it was WAY hotter than all the other corners. I wonder if pointing one of those digital temp gauges at the caliper or bearing would give accurate results too? I think this is an underlooked or rated way of troubleshooting and diagnosing a lot of issues and a money saver.

[Vancouver98STi]

Do you guys think those Digital Temperature gauges would work as well? I think this is an underlooked or rated way of troubleshooting and diagnosing a lot of issues and a money saver.

I think a INFRARED LASER THERMOMETER would work just fine for this purpose. I've seen them for as little as 20 bucks.

And maybe I should re-emphasize that I wasn't kidding about using the back of my knuckle.

[Phasewest]

IR cameras are super helpful. The trick is to understand the way the technology works and apply it in a meaningful way. IR temp guns are good, but they are usually set at the factory to work at an emissivity level of 0.95. This works great on something like electrical wiring and objects of similar composition. To jdmvip, a temp gun would work fine, as long as you were pointing it at the painted or rusty surface, your results would be reasonably accurate.

For something like a shiny brake rotor, you need to make sure that you set the emissivity on your device to something like 0.6. This is because the temperature recorded is always some combination of the actual emitted IR energy and the reflected IR. For example, if you were to stand in front of a large stainless steel panel or other shiny metal object and look at it with a suitable IR camera, you would actually see your IR reflection. That's how good the tech is these days! This is also why when using these things you need to take your images at an angle, so you don't inadvertently muddy the results with heat from yourself.

Generally, if you want accurate temperatures with a simple $20 IR gun, you should place some vinyl electrical tape where you want to measure. This will give you accurate results.

An example of something that IR can do if utilized properly is locate body filler in what appears to be a pristine car. The premise is simple enough, place the car to be examined in a garage, away from direct sources of heat. This lets the body of the car normalize to ambient. Then take the car out into the sunlight and film the car with an IR camera. As the sunlight heats the bodywork, places where it is thicker (body filler) will warm up at a different rate than the rest of the car, and will show up easily as a different temperature while the bodywork warms. It also works in reverse as the thinner steel sections will cool faster when placed back in the garage than the places with body filler.

If you guys have any other questions about how this tech can be applied let me know. I generally just use it for finding loose wiring in electrical panels, but I have been trained in it's application and use for everything else too.

One last thing, Vancouver98STi, that is super dangerous. Shiny things won't emit too much IR but can be ridiculously hot depending on the surface condition. I've seen stainless steel steam piping show on IR cameras at about 40C, but were actually at about 180C. Remember, the temperature you measure (and can feel at a distance) is a combination of Emitted and Reflected IR.

[Vancouver98STi]

One last thing, Vancouver98STi, that is super dangerous.

Oh come on... quickly rapping the back of my knuckle onto a brake rotor is "super dangerous"? No way. I haven't had my ugly calloused knuckle (any of them) stick to a hot chunk of metal yet.

Your knowledge of IR cameras is impressive (and thanks for sharing!)... but I know my knuckles.

[Phasewest]

A quick rap with the knuckles may not be too bad, but I've got nice scars from accidentally brushing against generator exhaust systems at work. I didn't think too much of it when I was an apprentice in my twenties, but you'd be hard pressed to see me working without long sleeves these days.

[Vancouver98STi]

...I've got nice scars from accidentally brushing against generator exhaust systems at work.

Oh man, your comment took me back in time to '73... my first job out of high school. I worked for four years in a shop fixing air-cooled engines. Everything from one lung Briggs & Stratton putt-putts to V4 Wisconsin engines. They powered generators or pumps or whatever you can imagine. Because of the layout of these flat-head engines, the carburetors were always located right next to HOT cast iron exhaust manifols. I used to burn my fingers/hands all the time while adjusting the carbs on these engines!

Here's a video I found online of an old Wisconsin V4 engine. Brings back memories (some of them painful!) from 40 years ago.