MC Stradale Brake Bolts

[Zep]

Morning Zep,

Thanks for your help on this so far - this may be an unanswerable question but I wondered what your thoughts are on re-using OE bolts from a donor disc? I've had the opportunity to get my car back on the road through the generosity of a local specialist who has donated enough bolts from an old worn/degraded disc that was destined to become a wall clock! I still very much intend to put new bolts in if you can help me source them, but I'm now in two minds about how much I should be running the car in the meantime with bolts of unknown health.

I've torqued them back to 10nm which I'd read somewhere, do you recommend a specific torque/angle rating when you supply the replacements?

Many thanks,

Subject to a thorough examination, I can’t see an issue with reusing the bolts.

I have the price now so will confirm it this evening for you.

 

[Fonzey]

Awesome, thanks Zep.

 

[StuartW]

Zep, would you suggest this is a sensible precautionary upgrade to replace the bolts or would you only look to do it if they are showing signs of corrosion?
I ask because of the caliper piston situation for example where I had a sticking piston on my first Strad which wrecked my pads, and this summer on my second Strad, I have had a similar issue which I spotted early enough so swapped them before any pad damage occurred.
Cheers

 

[Bebs]

Friend of mine recently had a catastrophic brake failure at a Silverstone track day in his 599.. corroded bolts! Apparently happened on a slow down lap but still fubared the entire assembly including the discs!

 

[StuartW]

Friend of mine recently had a catastrophic brake failure at a Silverstone track day in his 599.. corroded bolts! Apparently happened on a slow down lap but still fubared the entire assembly including the discs!

View attachment 119569View attachment 119570

Horrendous!

 

[Scaf]

Friend of mine recently had a catastrophic brake failure at a Silverstone track day in his 599.. corroded bolts! Apparently happened on a slow down lap but still fubared the entire assembly including the discs!

View attachment 119569View attachment 119570

Looks like he has a flat tyre as well - what a nightmare.
At least he can be thankful they were not ceramics!

 

[Zep]

Zep, would you suggest this is a sensible precautionary upgrade to replace the bolts or would you only look to do it if they are showing signs of corrosion?
I ask because of the caliper piston situation for example where I had a sticking piston on my first Strad which wrecked my pads, and this summer on my second Strad, I have had a similar issue which I spotted early enough so swapped them before any pad damage occurred.
Cheers

The construction of the disc is that the bobbin (the square bit that fits into the bell) is a long tube which is bonded into the rotor itself. The bolt runs through this and if it corrodes and expands it pushes the tube out into the carbon, causing cracks.

If they are replaced proactively, then yes, as the new bolts are a higher spec material (the originals are 304 stainless) then this issue is much less likely. I’d start with a thorough inspection.

 

[conaero]

We are seeing this, cracks on the back of the ceramic disc where the rotor bolts are braking out.

 

[Zep]

Friend of mine recently had a catastrophic brake failure at a Silverstone track day in his 599.. corroded bolts! Apparently happened on a slow down lap but still fubared the entire assembly including the discs!

View attachment 119569View attachment 119570

This is pretty horrific. The post failure damage to the disc seems significant so it must have been bouncing around for a while. There are some pretty heavy circumferential grooves under that damage so I am intrigued as to what has caused them.

 

[allandwf]

No failure is good, but that is horrendous, and potentially lethal, not just to the driver but others around them if it was to let go at speed. It's something most people wouldn't be aware of, you don't expect catastrophic brake failure.

 

[Bebs]

Looks like he has a flat tyre as well - what a nightmare.
At least he can be thankful they were not ceramics!

They were ceramics Sam.. unfortunately. Big bill.

 

[Bebs]

New disc assembly, new calipers, pads & new alloys now fitted —>

 

[Doohickey]

We are seeing this, cracks on the back of the ceramic disc where the rotor bolts are braking out.

Is there any particular age/mileage where you are seeing this?

 

[Scaf]

They were ceramics Sam.. unfortunately. Big bill.

Oh dear, you say “Bill bill” I suspect MASSIVE !
What bad luck

 

[StuartW]

The construction of the disc is that the bobbin (the square bit that fits into the bell) is a long tube which is bonded into the rotor itself. The bolt runs through this and if it corrodes and expands it pushes the tube out into the carbon, causing cracks.

If they are replaced proactively, then yes, as the new bolts are a higher spec material (the originals are 304 stainless) then this issue is much less likely. I’d start with a thorough inspection.

Good to know Zep and an inspection is definitely going on my list, thanks

I changed the bobbins & the bells on the Trofeo. They are a floating assembly which only fully tighten up when they are hot, but the rattling around when they are cold caused wear to both bobbin and bell and made a right racquet!

 

[Gazcw]

Looks like he has a flat tyre as well - what a nightmare.
At least he can be thankful they were not ceramics!

May have punched a hole through the wheel itself or cracked it hence flat tyre

 

[philw696]

Wow that must have been a huge bill indeed just shows that using cars and maintaining them correctly is a must.
If a car is a Garage Queen a thorough inspection needed before taking it out.