RX7 brake rotor failures

[pgipson]

There is a discussion on the production forum www.coloradoscca.org/prodcar/viewtopic.php?t=3291
concerning catastrophic failures of brake rotors, where the hub separates. I haven't seen this with our Spec RX7 group, although we did go through a period where we had some rotor failures due to cracking.

I was wondering if anyone has seen this on an IT prepped car.

[GEO46]

I myself have never seen this kind of failure on an IT car. Nor on the GT-2 1st gen that races at WHRRI. Broken spindles, now that's another story altogether.

[ddewhurst]

Paul, the hub/rotor failure looks like a bad part from the get go. That's why I asked Darren who the manufacture is. I understand the E Prod/speeds/race tires/forces & IMHJ that part was JUNK.

Now that Mazda no longer has Mazda rotors for sale I use Brembo rotors. Be careful because ALL rotors sold in Brembo boxs are not Brembo rotors. Look at the Brembo site for manufacturing details. Brembo rotors will have the Brembo logo stamped on he outside diameter of the rotor/disc & Brembo vented rotors have Pillar venting. Another key is that Brembo does not manufacture in Japan. There are also Brambo rotors manufactured in China sold in knockoff Brembo boxs.

Have Fun
David

ps: If anyone is cracking discs ask Mike Cox who uses this site how to improve disc life.

[dyoungre]

I did have such a failure, but the part did NOT come from Mazda - in fact, I'm not sure where it was from. Imagine: you hit the brakes, and you have a firm pedal, but an outrageous pull to one side - only under braking. I instinctively pulled off of the track, and then drove it back carefully, scratching my head. I jacked up the car, took off the wheel, and then spun the rotor. The hub stayed still, the rotor spun - yet the two halves of the rotor had captured the hub right where it broke, and so it stayed, radially, in place.

This rotor was obviously cheap quality, with extensive cracking before failure. My Mazda replacement have not had any of the radial cracking that this failed rotor had. Sufficient brake ducting, appropriate pre-treating (heat up to max temp in an oven, 500+, and then turn off and let cool naturally) and starting with a QUALITY part eliminated all rotor cracking for me.

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Dave Youngren
NER ITA RX7 #61

[gsbaker]

As bad as that is, it could be worse.

We have a customer who had a rotor explode on a 1/2 mile oval track. Not a big deal for circle track guys (they're always crashing into something), except one of the fragments bounced around in the engine compartment and lodged against the throttle linkage forcing it wide open.

So there he was heading into the turn 3 wall with full throttle at 130+, and all he could do was watch.

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Gregg Baker, P.E.
Isaac, LLC
http://www.isaacdirect.com

[Eagle7]

Originally posted by gsbaker:
We have a customer ...
So there he was heading into the turn 3 wall with full throttle at 130+, and all he could do was watch.

I hope he was a customer before this "test". Did you pass?

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Marty Doane
ITS RX-7 #13
CenDiv WMR

[gsbaker]

Yes, Marty. He was a customer and he still is. It would have looked bad saying, "We had a customer..." eh?

I'm not sure of the sequence; he may have had his crunch and seen the light.

[Edit: corrected sequence.]

Gregg

[This message has been edited by gsbaker (edited August 10, 2004).]