Front tires were on fire.

[8v-of-fury]

The car in question, a 1994 Jetta 2.OL gas.

Gf's sisters car (yes I have infected everyone with the vw lust lol). Yesterday she phones me up and says hey, so my front tires were just on fire. Apparently she pulled over because she saw smoke (good girl) and then saw flames coming from inside the rims. Doused them quick and phoned me.. I was at work so I had my bro take her wheels/calipers/pads everything off and have a good look around. One thing he noted to me was that there was a significant lip on the rotor and the pads look pretty worn... Normal you say? These pads/rotors have less than 5k on them. And already a noticeable lip? Either she rides em like a mofo coming to a stop, or the calipers are seized. My parts guy and air cooled guru suggested he thinks it was the bearings starting to cease up.. I support that idea except for even now (after the fire and obvious mad heat) there is no tell-tale bearing failure noises. Personally I think it was the brakes, but has anyone heard of pads catching fire?

Thanks guys 

[truckinwagen]

yep, I certainly have heard of pads catching fire, but only when stomped hard and long.

I do not know this girl, but I know my sister, who asked me to take a good look at her car that was "shuddering and shaking when I brake"
turned out there was nothing wrong with the car other than the fact that she was stabbing the brakes so hard and late that the ABS would kick in on dry pavement in town(takes ALOT of foot to do that)

of course it could be the wheel bearings too, as they begin to wobble the rotor/pad alignment goes out, wearing the pad and rotor very fast, they also make lots of heat.

but if it were bearings, I would expect there was lots of noise for a long time before anything caught on fire(same with stuck calipers, should make lots of bad noises before catching on fire)

-Owen

[8v-of-fury]

That's the thing... No noises of any kind. I have driven and ridden in the car many times. The car made a 30 min trip yesterday (town to town) and they were hot enough to catch fire?

Now I have only done bearings on an mk1, never an mk3... How do they come out?? I think replacing them anyway might be a good thing, as they're probably stock.

I wonder what can I look for to point me to a failing caliper? Watch its motion and see what happens?? See if it extends and retract smoothly? With the pads and rotor in place of course.. Don't wanna rip the seals... Lol

[R.O.R-2.0]

if the bearings are still tight, leave them alone, the bearings are a PITA to replace..

im willing to bet that its a bad master cylinder or a bad caliper tho, because i drove a wheel bearing soo bad that the front hub about came out of the knuckle..

and brake pads do indeed catch on fire.. my buddy and i caught his brakes on fire one day.. we finished a trip that usually takes an hour and a half, in 22 minutes..when we got to where we were going, there was smoke rolling, then i noticed one of the plastic hub caps starting to melt!

[Quantum TD]

I"d replace the rubber hoses too. They're probably melted anyways, but sometimes they degrade internally and the calipers can't release the fluid pressure. There's a good amount of pressure sending fluid to the calipers, but not so the other way.

[Dakotakid]

I think you will find that the problem is simply the way the dippy little beeotch drives! (There....THAT statement will keep the legal team busy for awhile!)

[theman53]

I"d replace the rubber hoses too. They're probably melted anyways, but sometimes they degrade internally and the calipers can't release the fluid pressure. There's a good amount of pressure sending fluid to the calipers, but not so the other way.

That is my mechanical guess. The rubber falls apart inside and acts as a check valve. I bet it has been doing it a long while to wear the brakes in 5K. And since it is rubber it sometimes isn't 100% all the time.

If not that I say x2 to Dakotakid

[8v-of-fury]

I told her the other day and I quote "Your head, it is full of air". She didn't catch on too quickly lol.

[macka]

does she have the same last name as you? Cuz you can always call her Hollowhead H******

[Baron VonZeppelin]

I've melted a couple of hubcaps in my day.
Both times it was a bad/stuck caliper.

Hoses do sound like probable suspects tho.

[745 turbogreasel]

On mine it was rust at the snap ring  preventing the master cyl from returning all the way.

[RadoTD]

Is she hot? 

[8v-of-fury]

Ok so I had a chance to look at the car today. Ripped both brake assemblies apart and inspected things. Everything was just dandy. Bearings tight and brakes were fine.

I bled both just to make sure it had some fresh fluid in it.. And then went for a drive. I got up to.. Let's say very fast.. And gaeared down to a stop.. Not using the brakes, and the rotors and bearing area were cold to the touch. Did a moderate to heavy stop from the excessive speeds to make my test completely conclusive.. And damn did they smoke.. Definitely not the bearing.. And I can't believe the airhead actually saw flames....

[RadoTD]

Possibly some sort of flammable liquid soaked into the pads and burned off? Something still left in there that you got smoking...
I think of replacing the brake pads either way, just to be safe

[theman53]

I would say hose, caliper, or master cylinder. I would lean away from caliper just because it comes and goes, but stranger things have happened.
Like Rado said maybe oil or cv grease got into them and is wrecking the friction material. Maybe try a can of brake cleaner if all else looks good.