Cracked Front Rotor (Disc)

[Duckster]

Hi, new on the forum.
Have a 2005 DiD, auto, and noticed the other day that my front rotors, left and right hand side, have cracks in them. Cracks are about 10 cm apart end run from outise to the inside.
Just to embark on another "round the block" trip and got in touch with my Mitsi dealer here in Perth to have them replaced.
Have been advised that this is NOT a warranty item. Car has done 45K, pads still are barely worn.
Was initially told that the cracks would have been caused by driving through a puddle whilst they were hot?! If that's the case, Ill better leave the car home on a wet day!
Any comments you guys?

[Eastie]

This could happen under emergency braking if the disks were already hot. It's would be mighty long odds that both left and right fractured due to faulty materials alone.

[Jaydee]

I wouldn't have thought vented discs could crack unless as you say quenched quickly when hot. Being the fronts they handle most of the braking but should be designed to tolerate some immersion without fatiguing.

It's amazing how new vehicle component life seems to be getting shorter and shorter.

[Loco]

get slotted (less fading) DBA kangaroo paws and fit them instead of factory then if there is no warranty. Don't get cross drilled though, guarranteed to crack then.

[72pug]

I would also recommend using an upgraded disc rotor if that is an option to you.

As for NOT using cross-drilled, i've heard lots of negatives in this area from people who have not had them themselves, but as someone who HAS used them and had NO problems with 2 separate sets of DBA GOLD slotted & cross-drilled...i can only give them a lot of praise. The current set is in a LR Discovery, which has Non-Abs braking, and they are @160,000k's currently.

Have also used these rotors in race-car application & found cross-drilled CAN crack under these extreme conditions with sometimes no cool-down period being available & pads sitting in one position for a while.

Sorry to Hijack the thread, just thought you would like the benefit of broad experiences.


Cheers,

Pug.

[OnPatrol]

It doesn't look like it's cracked to me. Maybe its just the quality of the photo, but it looks like the edges of the brake pads caused an indentation on the rotors after hard breaking. Did you get a brake specialist look at it? Sorry, like I said maybe its just the photo.

[Eastie]

I thought the same - it doesn't look like a metal fracture in the photo's but pictures don't always show the situation

[simoncurly]

I thought the same - it doesn't look like a metal fracture in the photo's but pictures don't always show the situation

Yeah i think you might need to have a closer examination of the "crack" I am thinking maybe they are corrosion pits where pads have been sitting stationary in a wet condition against the disc surface. If the pattern is the same both sides then that is more likely. It would be unusual for the crack patterns to be exactly the same on each rotor.

cheers

[Duckster]

Cracked Rotor?

Bit of an update, thank you all for your responses and feedback.
Still none the wiser, have today replaced the rotors with the Mitsi units.
All I am interested in how to prevent future problems.
Was advised that pads still had 60% left.
Most probable explanation was that the pads have been sitting in one place and maybe somehow there is some corrosion as per Simoncurly?s response.
Anyway, new rotors in place at great expense, wait and see.
Cheers, Tom.

[simoncurly]

Just an after thought .. did you keep the old rotors?

[mrbitchi]

Would be interesting to have a brake specialist look at them..

[Para Ordnance]

Personally, I would of had the rotors skimmed/machined, and then checked them thoroughly for any signs of "cracking".

If in fact they were cracked, I'd then request for a service rep from MMAL explain to me why normal wearing ( no hotspots or blueing visible ) rotors on my vehicle are cracking.

If that didn't work to my advantage, I'd then get aftermarket rotors for a third of the price of genuine.