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Exploding shocks

Discussion in '456/550/575' started by papou, Mar 30, 2018.

  1. papou

    papou Formula 3
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    May 18, 2012
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    daniel ross
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  3. wbklink

    wbklink F1 Rookie

    Sep 2, 2009
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    Wow I can’t wait to hear from our resident geniuses
     
  4. rubenpadron

    rubenpadron Formula 3
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    This happens when the suspension accumulators (aka bombs) fail and hydro lock, creating enough pressure in the shock body for it to burst and (rapidly) dump fluid.

    I don’t recall the exact manner in which the bombs fail that results in hydro lock, but this has been well documented before - search is your friend. :)

    I hope you an get back on the road soon!

    Ruben
     
  5. papou

    papou Formula 3
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    I’ve always known that to be the case, but I replaced my accumulator’s less than 2.000 miles ago,
    Thanks to Rob at Delta Vee he found a shock for me otherwise I’d be lost..
     
  6. scowman

    scowman Formula 3

    Mar 25, 2014
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    Interesting. Could your accumulator have failed so fast? What setting were your driving in? I'm wondering if the stiff setting damping is just too much for the shocks? Perhaps the shock body fatigues over time as it is partially (along with the spring) holding the car up. That metal does not look too thick.
     
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  8. papou

    papou Formula 3
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    Those shocks are DeltaVee rebuilds all 4 corners , I drive in sport most of the time flat good roads in S Florida, I spend 9 months
    every year in Atlanta working on MacGyver tv show for CBS coming home and just using the car on holidays, might it be the long
    time standing that could be the cause .
    D.
     
  9. tazandjan

    tazandjan Three Time F1 World Champ
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    Looks like she was driven off a cliff. Bad luck, Daniel.
     
  10. rubenpadron

    rubenpadron Formula 3
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    Weird , sorry to hear Daniel. Curious, how was the ride before this happened? When my accumulators went bad, the ride got super stiff (prob hydro locking) which prompted me to stop driving the car until I got new accumulators. Did you encounter the same?

    Another theory could be that there was prior stress on the shock from bad accumulators in the past and it just created a weak point in the shock that happened to rear its ugly head now.

    Either way, I’m glad you got a hold of another shock.

    Ruben
     
  11. au-yt

    au-yt F1 Veteran
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    Ouch that was expensive, Question when were the accumulators last changed.
     
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  13. 2HotShoes

    2HotShoes Karting

    Sep 2, 2015
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    Tal & Beryl
    Is this car a 550, 575 or 456? I wasn’t aware the 550 had accumulators and have to ask which models/packages have them. I had one blow in a Rolls once. NOT PRETTY. Seems to me our 550 has much more straightforward suspension, however, if the car has these IEDs I’d like to know about it...
     
  14. papou

    papou Formula 3
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  15. papou

    papou Formula 3
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    Image Unavailable, Please Login These are the ones I put on
    These are the ones I replaced with.
     
  16. scowman

    scowman Formula 3

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    The Amazon are made by bilstien. The ones you show probably are as well as are the Ferrari. Likely only one maker. I wonder if there is a way to determine if the bomb failed. I’m starting to think many failures are being blamed on bombs when it’s just the shocks giving up after so many years of holding the rear end up. Again that metal looks very thin. I looks like an alloy as well. Not steel.
     
  17. papou

    papou Formula 3
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    We all seem to agree that the DeltaVee upgrade is the way to go, but is the bilstien original spec like a fuse so the
    shock does not explode.
     
  18. scowman

    scowman Formula 3

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    I don’t think the DV upgrade really has any impact on the shock failure one way or the other. It is just seals and maybe some machining. I also think all the bombs are the same from the same manufacturer. I really think either the bombs are failing or the shock bodies are just giving up. Maybe some of both. Were they really built to hold the car up for decades? Remember most cars are suspended entirely by springs which eventually sag and get replaced. Most shocks just dampen spring recoil. These shocks do both.
    Did bilstien build beefier shock bodies for the added load of suspension? It would be interesting to cut through some 550 shocks and compare the wall thickness to the 456. If they are the same I would be suspicious and expect failure eventually.
     
  19. papou

    papou Formula 3
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    That makes sense, question is what do we do in the future, I’m keeping my 456 beauty reason only but about to purchase
    a ff I know I know “The beauty & the beast “.
     
  20. scowman

    scowman Formula 3

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    I’m thinking a couple of things.

    First I may buy one or two rebuildable core shocks. I’m not certain of the supply of these if this keeps happening and we start running out. Maybe some research into supplies and possible other uses for this shock body. Was it solely used on the 456 or are there others? We just need the same lower body. We can swap the other parts out.

    Second I’m thinking about reinforcing the lower shock body with a sleeve of some sort. It seems strange to me that that is the weak spot in the system. It’s metal. Usually the rubber parts blow out first. I’m becoming much more suspicious about the shock bodies. I’m thinking bilstien went cheap on the shock body and just used the same metal stock they used on regular shocks that don’t see the pressures these hydro units do. The sleeve would prevent the body from expanding.

    The downside is what gives next? Bent shock rod? Send the rod through the top mount and actuator? I’ve bent shock rods before off-roading. Not a big deal. But that puts us in the same spot. Busted shock. What I would like to happen is a blown shock line. Maybe a relief valves of some sort? What pressure?
     
  21. rubenpadron

    rubenpadron Formula 3
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    That’s an interesting point Stu... I’ve not heard of burst lines (going from memory these are rubber - I don’t believe they’re metal stranded lines) with failed bombs. It seems like the lines would be the weak point and not the shock body in the event of a hydro lock?

    Perhaps I’m missing something, but it seems plausible that metal fatigue in the shock body could be associatd to this, all likely kicked off by failed bombs. Sleeving may be a solution- ideally the lines would be the next weakest link, but who knows, it could be the rods!

    Ruben
     
  22. Gizzi

    Gizzi F1 Rookie
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    Search in this section and you will find a thread on exactly this issue. The forensic work done by the originator of the tread is amazing and tells the full story of the failure and analysis.


    Sent from my iPhone using Tapatalk
     
  23. wbklink

    wbklink F1 Rookie

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    If you have it please post the link..
     
  24. scowman

    scowman Formula 3

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  25. scowman

    scowman Formula 3

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  26. 166&456

    166&456 Formula 3

    Jul 13, 2010
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    The shock burst failure is 100% sure because of no air cushion left in the accumulators. The bladder inside them can fail, losing the cushion of pressurised nitrogen gas (at 22 bar so be careful and do NOT disassemble etc) behind it. While driving the shock will continually go over the designed pressure limit especially when going through a pothole. This will invariably lead to metal fatigue.
    Its cheap Insurance to replace them once they reach 15-20 years of age.
    Testing them is relatively easy once off the car. Test carefully with a blunt 3.5mm pin into the pipe connection, blunt and little force - you dont want to pierce the membrane inside! I suppose that could even be dangerous if you do. If you can feel the rubber membrane at the entrance and cannot easily push it in, it is most likely not failed. It might still be at too low a pressure though which is why replacement is a safer bet.
     
  27. scowman

    scowman Formula 3

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    That seems to be the common assumption but I don't see the evidence other than everyone repeating the same thing.
     

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