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456 suspension diagnosis. Pressure accumulator (cells, spheres) 2nd opinion please

Discussion in '456/550/575' started by skl63, Sep 28, 2009.

  1. skl63

    skl63 Karting
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    Dec 13, 2007
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    Scott
    Hi,

    Our 97 456GTA is very (very) harsh riding and makes everything rattle. Switch on dash does little if anything. It is almost as if the rear shocks are locked solid.

    Anyway, I have been to a suspension specialist (works on road and race cars, inc. F-cars) who has suggested rebuilding all four shocks and replacing the pressure accumulators. This I am unsure about, because after speaking with Ferrari Australia, they tell me they have never had to supply a set, nor even price them. Has anyone here had to replace an accumulator?

    The suspension guy suggested that he believed the accumulators look to be the same as those on either a Citroen or a Benz, which sell for about $100 as opposed to Ferrari at about $1400. Any thoughts.

    He also suggested replacing F & R lower control arm rubber bushes, steering rack ends (ball joints nearest the rack, but not the tie rod ends).

    Alarmingly, we also discovered that one of the front Red shocker actuators is actually missing, so will probably try one of Dave's modified Corvette actuators.

    Any advice from the wise men out there?

    Thanks

    Scott
     
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  3. SonomaRik

    SonomaRik F1 Veteran
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    #2 SonomaRik, Sep 28, 2009
    Last edited by a moderator: Sep 7, 2017
    Typically when they lock down, the indicator light goes on: looks like a side profile of the car with tiny up carrots "^" under each tire, something like the attached

    Doesn't mean you don't have a lock down, but typically in these cars that is the symbol to see.


    Shocks are not a bid deal to rebuild. Check out the '456 car site thead' http://ferrarichat.com/forum/showthread.php?t=218347 in this section and follow some of the links on 456 shocks.
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  4. skl63

    skl63 Karting
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    Has anyone had an accumulator fail and is there a way to test them?

    BTW, thanks for the feedback Rick, but the light does not come on, which is also curious given the missing actuator.
     
  5. tazandjan

    tazandjan Three Time F1 World Champ
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    #4 tazandjan, Sep 29, 2009
    Last edited by a moderator: Sep 7, 2017
    skl- No service parts on the accumulators so replacing them is the only option if they need replacing. They are pretty simple and are just cylinders with a membrane inside to dampen out variations/pulses in hydraulic pressure from the pump and reservoir. If a cheaper one will fit, no reason not to use it since the Cotroen was much more hydraulic intense than your 456.

    Did your technician bleed the system to make sure there was no air in the lines or components? That would seem to be the first step. Making sure the fluid tank shared with the power steering is operating properly would seem to be the next step.

    The shocks can be easily rebuilt and the pros here recommend Delta Vee: http://www.deltavee.net/parts.htm

    Dave's actuators are indeed the best way to fix, and in your case, replace actuators. That missing one means you are missing some parts needed to do the conversion, however.

    Taz
    Terry Phillips
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  6. jbornwina

    jbornwina Rookie

    Mar 15, 2008
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    A citroen dealer would be able to test the spheres provided they are of the same thread. Citroen spheres are able to be overhauled by specialists I believe - a company called Pleiades (google it) in the UK may be able to help
     
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  8. Rifledriver

    Rifledriver Two Time F1 World Champ

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    Lots of people recharge bad accumulators.

    When the suspension light is on it is often in response to a "Locked" actuator. That does not equate a locked shock. It only means an actuator has failed and reset to a predetermined, midway position.

    Your symptoms can be explained by a bad accumlator. It doesn't really matter if it has never happened before. We see new things break every week. Every mechanical device will fail sooner or later. I do however get a warning light when they decide to throw in a suggestion to rebuild every component in the steering and suspension. It might need it but it still rings an alarm bell.
     
  9. Dave 456

    Dave 456 Formula 3

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    #7 Dave 456, Sep 29, 2009
    Last edited: Sep 29, 2009
    Scott,
    Be careful with the Citroen sphere/accumulator idea, the working fluid may not be compatible as they do not use power steering fluid. How ever I'd guess that a Cit specialist could test it for you - I'm sure that there would be someone in Melbourne. There is certainly an outfit in Sydney that can rebuild spheres. If the diaphragm is damaged, its going to be a problem. Since Ferrari often use other manufacturers parts, or very close, the M-B idea might be a good one.

    I don't understand about the harsh ride though - I normally use mine in intermediate as I find the soft setting a bit wallowy - there is a noticable difference in the shock settings. Also, and I'm happy to be corrected, the accumulators are part of the self levelling system; with the accumulators not functioning, I think the shockers would still work normally. Are you sure that the springs are standard? maybe someone thought they'd be clever and make an "improvement"..
     
  10. Rifledriver

    Rifledriver Two Time F1 World Champ

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    The pressure in the accumulator provides the "Give" in the shocks. Without it they are rock hard. It has no self levelling function.
     
  11. Dave 456

    Dave 456 Formula 3

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    I stand corrected! What does provide the self levelling function - is it entirely within the shock?
     
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  13. Rifledriver

    Rifledriver Two Time F1 World Champ

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    #10 Rifledriver, Sep 30, 2009
    Last edited: Sep 30, 2009
    The shock is a hydraulic ram that raises and lowers by a pump filling it to greater and lesser degrees with fluid in response to a height sensing device.

    Neither the spring, the shock or the accumulator pressure support the car by themselves. It is a joint effort. The shock and the spring provide support. The spring and accumulator provide give or spring rate.
     
  14. kosmo

    kosmo Formula 3

    Oct 19, 2008
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    Taz are the accumulator item #54?

    Rik your pic reminds me of the Oscar Meyer Weiner Truck!
     
  15. tazandjan

    tazandjan Three Time F1 World Champ
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    Kosmo- Affirmative, #54 @~$600 each. Seems like someone like Delta Vee could make some money refurbishing those as well as shocks. If not too expensive, might make sense to swap them out as the shocks are rebuilt.

    Brian- Does synthetic ATF extend the lives on those accumulators?

    Taz
    Terry Phillips
     
  16. spiderscott

    spiderscott Formula 3

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  17. bergxu

    bergxu Formula 3

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    Ok guys, the accumulators on the 456 cannot be recharged like a Citroën sphere. The Citroën sphere can be disassembled and serviced whereas the 456 sphere is sealed. It's the same as a BMW part, used on the X5 SUV and very similar to the ones used on Mercedes wagons of 1980s era. Just buy the spheres from AutohausAZ or the like. Look them up for a BMW X5. Only thing you'll have to do is add a fender washer on the mounting bracket as one of the holes is larger than the original Ferrari sphere bracket was.

    Once they're changed, fire up the car and add ATF to the power steering circuit as needed to bring the fluid to level. Take the car for a drive and check/correct fluid again.

    One thing is to be careful when cracking the 11mm fitting on the old accumulator. Crack it loose just a bit at first and let the pressure bleed off before undoing the line further. And when you go to refit that line to the new accumulator, leave the accumulator loose in the bracket so you have some wiggle to make sure you don't cross thread that line, it's easy to do.


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  18. scowman

    scowman Formula 3

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    It does fit the 456 BTW
     
  19. scowman

    scowman Formula 3

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    #17 scowman, Nov 10, 2018
    Last edited: Nov 10, 2018
    Can’t believe he set the box on the 355. That looks like a testarossa in primer gray on the right. Can’t ID the red one in the driveway...
     
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  20. spiderscott

    spiderscott Formula 3

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    I think my other cars were:
    Testarossa Spider .....see my full build on here over in Testarossa forum
    355 Spider
    308 GTS
     
  21. spiderscott

    spiderscott Formula 3

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  22. spiderscott

    spiderscott Formula 3

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    or this for fun .....

     

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