Very strange .......

Damn it Alcoa!

...To be honest, it's an interesting problem. Odd indeed.

Have you used the car on less than pristine surfaces before? Hitting many holes over a long period of time may have simply spread a little ding into what it is now... Of course, I'm no expert.


_J

 

VERY odd......."calling Rifledriver".......he'll know!

*shining spotlight beacon towards the West Coast*

He's not on this evening, maybe send a PM in the AM....LOL!

 

That looks very much like an overpressure fracture.

 

Thats not cool at all...


PDG

 

Can you tell if the metal looks a little thin in the area of the fracture?

 

You actually got two adults in the back of a 456?

 

Ouch!!! good thing you made it home safely.

 

I'm missing the connection with the power steering reservoir.
Does the 456 have adjustable ride shocks, driven off the power steering fluid?
...
Okay, I did some quick googleing. Most of the reviews indicate that the 456 has aluminum, 3-way adjustable, gas operated shocks, but that the power steering pump is used for the self-leveling rear suspension. (Without much detail on the self-leveling mechanism itself.)

So, without further data, my tentative guess would be that the shock blew out, and the self-leveling system tried to compensate.

There might be an issue with a seal in the self-leveling system.
"Leaky shocks" is a pretty common complaint you see on 456s.
(That, and the non-sealing windows, perhaps fixed on the "M".)

From the blerb sheets, the 456's suspension is actively computer controlled, based on speed, steering angle, throttle position, two axis acceleration, and brake system pressure. So a shock blow out could, conceivably, have been the suspension ECU getting its sums wrong. (Possible sensor fault.)

But you should get an "expert" opinion. (E.g., someone who's worked on one ---- or who has actually seen one up close. )

 

Holy cow!! I have never seen a shock blow out like that!

Glad you and your friends made it home safely.

I wonder how many times this has happened in other 456 Ferraris.

 

+1

Definitely overpressure.

 

I lost this thread yesterday...PM Rifledriver....maybe get a Moderator to move it to 456 Section, and re label it something sexy like:

"WTF! Rear Shocks EXPLODED and almost KILLED me!"

THAT will get the proper attention! LOL!

 

must have been an imperfection there for it to do that. I would think they designed those with a pretty good safety factor.

Thin wall pressure vessals!!!!

 

I agree with "material failure" but a pressure valve or pump could be overcharging it......

 

Overpressurization is most likely the correct cause but the linear orientation implies a high stress area like a longitudinal seam.

 

Never seen one do that before. Looks like it was leaking for some time prior from the top seal judging on the accumulation of grime on it.


Looks like you are in the market for some new shocks.

If you had a bad level sensing valve and it over pressured the shock it would have been riding very high in the back to the limit of travel before pressure could go up. If it is a bad accumulator that should insulate the shock from pressure spikes due to rapid shock compression it would ride very hard, like solid suspension. If neither was happening it was a simple shock tube failure.

Bilstien never did know how to make a good shock. When Ferrari changed to Bilstien we changed so many bad shocks I felt like I was working at Pep Boys.

I'll take Koni any day. I'll even take a Monroe over a Bilstien. The Germans should stick to fuel injection and leave shocks to someone who knows how.


By the way, do you own a TZ750? Very cool motorcycle. Those owned the race tracks in very much the same way Porsche 917's did.

 

There you are! I just sent you a message.....

Looks like a hidden flaw (weak spot) then, in the extrusion?

 

Is it fair to slam Alcoa? Were they even involved?

 

Are you sure its extruded? I see a few telltale signs of a welded seam failure.

 

A tubular pressure vessel will tend to burst in a straight line along the length of the vessel, like shown in the pic, because the "hoop" (or tangential) stresses are the highest in such pressure vessels.

 

Have you checked the other shocks for the signs of similar blisters or bubbles?
How much presure would cause this, and what other parts of the system are exposed to them?
Maybe try to find what the internal valving looks like, maybe a seal failed and two seperate chambers "charged" one small area.
Sorry to ramble, I'm not familiar with this, but does the ride adjustment use adjustible air presure? Could condensation introduce water into the system, it settles to a low area, during operation it heats up turns to steam and blows out the lower shock body?

 

are those two little nicks in the second picture? right above to the left of the blowout?

 

Well I'm not exactly taking them to court.
Just a fist wave at a general Ferrari supplier.
But no, they were not involved... I don't think.


_J