Hairline cracks in rotors ? WTF ?

[Strich9ine]

A mate of mine just got told he has hairline cracks in his disc rotors ? WTF is that ?

It's a 97 camry (no camry jokes pls!)

What causes this also ? and is it safe to drive with these ? or is the mechanic pulling his chain ?

-Kym.

[psssi98]

Can happen on any car and any rotor depending on age, treatment etc...I'd get a second opinion but if the person that told you they are there can see them you should be able to as well...just take the wheel off and have a look!!

A hairline crack is just a very fine cracking of the surface!!

[Kangz]

Yep, Cam is on the button.

Go out to your mates car with some brake cleaner. Spray it on the discs, see if any pools while running off, say following a hairline crack for instance!! Make sure your hands are clean, and run a hand or finger nail over them.

Or else get a second oppinion.

Driving with cracked rotors isn't the best idea. If they shatter, and something lodges in the calliper at 100km/h, good luck.

[Tex]

I believe that when rotors begin to wear to the point that they need to be replaced, the surface shows cracks like these.

I may be wrong though. I'll move this thread to the brake forums so someone who knows what they're on about for sure can answer you!

Tex

[hotgemini]

Nah, if you try hard enough you can get fine hairline cracks or tracking across new disks...

If it is just tracking and NOT actual 'all-the-way-through' cracks, then it isn't a big concern, on the other hand, if it is actual genuine proper cracks, he will want to replace his rotors quick smart.

Get someone who knows there shit to have a look at it and pass judgement.

[Kangz]

Originally posted by Hotgemini
Get someone who knows there shit to have a look at it and pass judgement.

their

[hotgemini]

Originally posted by Kangz

their

Bored?

[Raynman]

Make sure you get them checked if you are going to reuse them.

I jammed a caliper on my rally car, made a new mount and set off again.

The disc must of had some very fine cracks in it as it disintigrated after about 20km of driving doing lots of damage.

This can be read as shattering the disc into losts of pieces (I only ever found 3), snapping high tensile bolts, losing the caliper and mount (if you find it in the Heathcote forest its mine), damaging the diff mounts, severing the brake lines, bending a brake pad and damaging the inside of the wheel.

IMO if in doubt replace it.

[Spac]

THe cracks are almost certainly due to excess heat. Race car guys ruin heaps of discs this way. If the cracks can be machined out (without going too thin) they'll be fine. If you leave them, they will get worse, and eventually will let the disc fall apart, like Raynman described...

And "eventually" is an indertimanite time frame - a week? A month? Longer? I don't know, neither will you, but I sure as hell wouldn't want to take the risk! :)

[dbasteve]

Sorry I missed this one.

This is a document I did for a Police workshop on crazing ( Surface cracking)