Brembo Rotors

I recently had a call from a first gen Mazda customer whose Brembo rotor he just purchased lasted about three laps before it parted from the car. He called a reputable Mazda prep shop and asked them about it and was told that they have a couple thousand dollars in replacements and that this is a factory defect. Apparently the threads are bad in some way. However, Brembo will do nothing about the defect, not even talk about it. This can only mean they have a lot of them out there and have something to hide, in my way of thinking.

If you have purchased Brembo rotors please inspect the internal stud threads to make sure they are well formed and complete. Exactly what the problem is is unclear but you will be able to tell by close inspection if there is some problem with the threads.

Has anybody else had problems of this sort with Brembo rotors? Have you heard of someone else in any class having the same experience?

This could be a serious safety issue besides the thousands of dolllars that this may cost retailers and racers.

Jim Susko

My previous statement on this subject was meant to say the wheel parted from the car when the studs pulled out. Apparently when I edited it I failed to update my edit. I apologize for any confusion.

Jim Susko

Wow. That is really bad. Ive used Brembo rotors (solid surface) for two years on my ITA Civic and have never had an issue with them. Next time Ill be sure to take a look at them before installation. I havent heard of other drivers talking about it.

Very interesting...

I've used them when I can source them. Which isn't that often. No issues here. Too bad the design makes us have to replace the whole thing everytime the things crack, and it adds extra expense for bearing replacement.

Greg,
I don't know about the Honda design, but the 1st Gen RX7 used wheel lug bolts, not pressed in studs. The integral brake rotor / hub is threaded, and most racers then thread studs into the brake rotor to enable the use of lug nuts, instead of using lug bolts. I'm guessing that the honda rotors are either captured between the wheel hub and wheel, or use pressed in studs? Like I said, not familiar with the Honda design, but wanted you to know the unique design 'feature' of the RX7 brake rotor.

Further to Daves point, the wheel mounting surface is less than two inches away from the brake disc, which makes it impossible to press a stud in from the back. So the studs used are, in my case, double threaded, The short end threads into the disc/hub, then bottoms out on the non threaded portion of the stud, The lugs thread on the exposed threads. They are torqued via an allen wrench from the external end. (and red locktited)

Yuk.

If i weren't doing enduros and cared about fast wheel changes, I'd use bolts before using those thread-in studs. Unless wheel thickness/spacers become an issue...?

K

Quote:

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Originally Posted by Knestis

Yuk.

If i weren't doing enduros and cared about fast wheel changes, I'd use bolts before using those thread-in studs. Unless wheel thickness/spacers become an issue...?

K

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Bingo. Not to mention the bolts are a major PITA. And, if you think about it, the failure mode being discussed here would occur with wheel bolts as well.

Quote:

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Originally Posted by Jim Susko

I recently had a call from a first gen Mazda customer whose Brembo rotor he just purchased lasted about three laps before it parted from the car. He called a reputable Mazda prep shop and asked them about it and was told that they have a couple thousand dollars in replacements and that this is a factory defect. Apparently the threads are bad in some way. However, Brembo will do nothing about the defect, not even talk about it. This can only mean they have a lot of them out there and have something to hide, in my way of thinking.

If you have purchased Brembo rotors please inspect the internal stud threads to make sure they are well formed and complete. Exactly what the problem is is unclear but you will be able to tell by close inspection if there is some problem with the threads.

Has anybody else had problems of this sort with Brembo rotors? Have you heard of someone else in any class having the same experience?

This could be a serious safety issue besides the thousands of dolllars that this may cost retailers and racers.

Jim Susko

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Jim, the answer is yes and yes.

I have had a rotor have this issue, luckily it was only one stud so I never lost a wheel. I first heard of this problem with Brembo rotors about two years ago.

For what its worth:

I have used Brembos with no previous issues and employ 1/2-20 studs (cut to desired length) and using a low profile lock nut on the back side.....and using copious amounts of red lok-tite on all threads.

I also have a new set of Brembos that I have examined closely and all appears to be well with those, which have not yet been drilled & tapped......

Quote:

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Originally Posted by Knestis

Yuk.

If i weren't doing enduros and cared about fast wheel changes, I'd use bolts before using those thread-in studs. Unless wheel thickness/spacers become an issue...?

K

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Yes, the studs I have only have a limited engagement before they bottom on the unthreaded portion, so they put more stress on the threads. On the other hand, the fact that with Loctite the threads remain engaged and undisturbed with wheel changes means less wear and tear on them. Ideally, one should have a stud with continuous threads that can be inserted the same depth as the axle flange threads and loctited in. Does anyone have a source for such a stud?

Jim-
I'm the one who called you after having my left front wheel seperate from the car at speed. Even though all four studs pulled from the Brembo rotor I decided to look outside of just a possible rotor failure. A Brembo rotor for a first gen RX-7 has 18mm available for stud thread engagement. Most studs available from the RX-7 aftermarket world have only 9mm of engagement and the unthreaded area of the stud is so small that you can keep threading the stud in past this area thereby damaging your rotor threads. They also cannot provide any specs for there studs.
I have talked with my fellow PRO-7 racers here in the Pacific Northwest, numerous engineers, engineers from ARP and Maryland Metrics and local machininsts. Finding a double ended stud with 18mm of engagement is very difficult. I ended up purchasing 12mm X 1.5 studs from Turner Motorsports. They are 75mm long with 13mm of engagement and 12mm of unthreaded area which is perfect for a 1/2" wheel spacer. Another racer is awaiting studs from Maryland metric which have 24mm of engagement. I will look at these also.
Most likely I will run the Turner Motorsport studs with my current batch of inspected Brembo rotors next season and keep a close eye on this new set up. I appreciate the help Jim.
Duane

This weekend I installed a fresh pair of Brembo's on the front of my RX7. When I attempted to torque the wheel nuts two of the threaded holes on the rotor stripped and the studs pulled out of the rotor. This was the first time the wheel nuts had ever been installed so it is very difficult to point to this being anything other than defective Brembo rotors.

In the absence of a source of fully threaded studs I used a die to thread the studs the entire length. You need to start from the hex end and work your way toward the rotor end of the stud. You then install the studs backwards. I.E. the end with the hex opening goes into the rotor(If needed, double nut the end of the stud to be able to use a wrench to install them). The reason you need to install them backwards is because the other end of the stud which is normally in the rotor now has a very weak thread on it because the die recuts these threads (poorly). However, if you are using studs that are long enough this weak area doesn't get used because it extends beyond the wheel nuts. This is the first time I've done this so I don't know if these studs are going to be reusable or removable, but I'm pretty confident my studs aren't going to pull out of the rotor because I have 100% engagement now. YMMV.

I use the ones from Turner, or the same ones sold by a VW place called Norschlagg or something similar. No issues. But I haven't seen a Brembo available in a long time. At least four sets of rotors and bearings ago.

I've never had a thread issue with brembo's. I did receive one small bearing brembo rotor damaged somehow in manufacturing or transit that had a massive crack running accross the rotor surface tangent to the central hub. They are still my rotor of choice (best combination of durability, cost, and weight).

Tak