Help, weird build-up on brakes

"Tom McParland" (tommcparland)
08/28/2015 at 15:55 • Filed to: brakes, 2015 Volkswagen GTI

So recently I heard a slight thump-thump when ever I hit the brakes. On my passenger side, rear rotor I noticed this weird build up, which I suspect is causing the noise and is why the rust isn’t getting cleaned off. Anyone ever experience this? Yes, I know my wheels are dirty #dadlife.

Close up -

I was able to chip a little away with my finger, but I don’t want to experiment removing it with anything sharp. I figure I’ll take it to the dealer as this type of thing should be under warranty...I hope.

Any suggestions...solutions?

DISCUSSION (22)

deekster_caddy > Tom McParland
08/28/2015 at 15:58

That sure looks like brake pad. I’d say a piece of brake pad came off and bonded to the rotor. Defective pad?

Ought to be covered by warranty.

Will with a W8 races an E30 > Tom McParland
08/28/2015 at 15:58

Looks like a nasty pad deposit. May get lucky and be able to machine it off, but easier to just replace the rotor. Check your pads while you’re at it - material had to come from somewhere.

crowmolly > Tom McParland
08/28/2015 at 15:58

Tom, are you sure you still HAVE rear brakes at this point? You may have just a front circuit. That buildup could also be pad material.

Both sides look the same?

Party-vi > Tom McParland
08/28/2015 at 15:59

Seems like something got between your pad an rotor, or maybe your caliper seized up. Either way, shit’s broke.

d15b > Tom McParland
08/28/2015 at 15:59

Do bring it into the dealership. Being able to stop your car...is important.

With that being said, I think that rotors are a wear and tear item, meaning it might not be covered under warranty. Just a head’s up.

Twingo Tamer - About to descend into project car hell. > Tom McParland
08/28/2015 at 15:59

Definitely looks like somethings faulty. Use dat warranty.

SnapUndersteer, Italian Spiderman > Tom McParland
08/28/2015 at 15:59

Take it to the dealer yet?

Are your pads crumbling? They could be if they’re low

Tom McParland > SnapUndersteer, Italian Spiderman
08/28/2015 at 16:00

Pads seem ok

Jcarr > Tom McParland
08/28/2015 at 16:00

Better call Lehto!

Tom McParland > crowmolly
08/28/2015 at 16:01

Driver side rear is fine...front brakes are fine

ADabOfOppo; Gone Plaid (Instructables Can Be Confusable) > Tom McParland
08/28/2015 at 16:01

That looks like surface rust. I bet Party-vi is correct and your caliper is partially seized. Dealer should fix that for you.

HammerheadFistpunch > Tom McParland
08/28/2015 at 16:02

Looks like a chunk of the pad came off, maybe after a hot drive if was parked then it cooled rapidly or something.

crowmolly > Tom McParland
08/28/2015 at 16:02

Can you use a mirror to check pad thickness?

Highlander-Datsuns are Forever > Tom McParland
08/28/2015 at 16:04

Definitely a warranty claim, I mean subaru replaced two year old windshield wipers on my car because they were worn out and were streaking.

Svend > Tom McParland
08/28/2015 at 16:04

Has your car been sitting for any length of time after a particularly wet period or driven through a relatively deep puddle or even washed the car and left?

It may be that some water has accumulated behind the wheel hub and has slowly been seeping back out and coursed a more pronounced area of rust build up as the vehicle has sat.

Tom McParland > Svend
08/28/2015 at 16:07

It did sit for about 5 days without me driving it.

RWS Motorsport > Tom McParland
08/28/2015 at 16:16

Is the pad seated properly in the caliper? Cause it looks like irregular wear rather than damage to me. Might be worth removing the caliper and checking the piston moves and the pad is ok.

Or throw it at VW and tell them fix it.

Textured Soy Protein > Tom McParland
08/28/2015 at 16:20

Since it’s been sitting for a while, to start with I’d just try giving it a few hard stops and see if that scrapes off the crud. It might look bad but could be nothing. If it’s still there, then sure, take it to the dealer.

Svend > Tom McParland
08/28/2015 at 16:24

Turning picture one on it’s head it looks (I’m only guessing) that water has accumulated as I say behind the wheel hub or above the rotor and gradually seeped out.

Kinja'd!!!

But ye’, certainly worth getting it looked at as may cause damage to the pads if not already done so especially under heavy braking. May just need machined smooth but may as well just change it.

bryan40oop > Tom McParland
08/28/2015 at 16:30

Pad isn’t seated correctly. Could be misaligned due to foreign object knocking it out of alignment.

You’re only making contact on outer edge of rotor thus the rust build up on the inner part. Machine rotors install new pads. No big dealio.

Seen this all the time.

jariten1781 > Tom McParland
08/28/2015 at 17:08

Echoing; looks like the pad is seated improperly for whatever reason. Play really nice when you take it in, they are absolutely not obligated to cover this under warranty but may, very likely as a good-will.

6Cylinder > Tom McParland
08/28/2015 at 19:15

This is odd as one good stop should have taken all of the rust off. Part of the pad isn't contacting/doesn't exist.