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Collapsed vacuum canister... what happened?

Discussion in 'Boxers/TR/M' started by raysur, Jun 27, 2019.

  1. raysur

    raysur Formula Junior

    May 3, 2008
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    Jeff
    I have my engine out on my '90 (21k). I just replaced all the fuel hoses and stumbled across this: Image Unavailable, Please Login
    This is located in the driver's quarter panel with two vacuum lines coming to it. The car was mechanically fine before the engine out. No driveability issues. What caused this and what did it effect?
     
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  3. vincenzo

    vincenzo F1 Rookie

    Nov 2, 2003
    2,929
    OEM vacuum pump?
     
  4. Steve Magnusson

    Steve Magnusson Two Time F1 World Champ
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    Jan 11, 2001
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    #3 Steve Magnusson, Jun 27, 2019
    Last edited: Jun 27, 2019
    It's the vacuum reservoir for the AC system flap motion system (so that there's a high vacuum always available to move the ACflow direction flaps around regardless of what the engine is doing) -- item 44 here:

    https://www.ricambiamerica.com/car-diagrams/ferrari/v12/testarossa-group/testarossa-1990/air-conditioning-system.html

    As long as it is not punctured, you probably wouldn't notice any AC operational problem (even though its internal volume is reduced some in that collapsed state). My guess would be there is some corrosion going on inside that weakened its structure. If it did/does have a hole in it, it wouldn't have any effect at all on the engine performance, but your AC flap system wouldn't work.
     
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  5. raysur

    raysur Formula Junior

    May 3, 2008
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    Thank you Steve!

    This thing is built like a coffee can. But a $175 coffee can.
     
  6. Steve Magnusson

    Steve Magnusson Two Time F1 World Champ
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    It almost is ;). The circular ribbing features (and the end caps) are designed so that even if the pressure inside goes to a complete vacuum, it still shouldn't implode. Another possibility might be that it inadvertently got "dented" during a previous service. Its ability to resist collapsing under vacuum is very dependent on its symmetric shape so even a small local dent can greatly reduce it resistance to collapsing -- just a thought...
     
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  8. jjeffries

    jjeffries Karting

    Sep 4, 2012
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    John Jeffries
    Fascinating. I notice than in today's cars, when you ask the HVAC to change mode (say from DEF to dash vents), the system slows down the blower motor while the stepper motors (as opposed to vacuum motors) affect the requested change, so that the stepper motors, their gears and the vents' pivot points don't have to fight the pressure/higher airflow of the blower. The mode change is completed and the control unit restores the fan speed to where it was before you asked for a change. All this progress was iterative from your vacuum canister, which was probably pretty slick in the 1960's. Sorry for the ramble. John
     
  9. turbo-joe

    turbo-joe F1 Veteran

    Apr 6, 2008
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    romano schwabel
    you may try to put some airpressure into this canister, may be it will blow up right again? but be carefull. try first only with 0,1 bar and raise to max. 1 bar. put the canister into water when you try this. so if it will explode not much will happen. when you do this it is on your own risk and I´m not responsible ;)
     
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  10. raysur

    raysur Formula Junior

    May 3, 2008
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    Jeff
    I'll give it a shot. I'll post the results soon. I want to see if I can hide another unit inside this one. Otherwise I'll source a new one.
     
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  12. gburkett

    gburkett Karting
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    May 25, 2012
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    These coffee cans were on almost all US production cars in the 70s and universal replacements are readily available. Since that one is hidden , you could source one with two vacuum ports from any parts house and it should do the job. In fact this one has a striking resemblance to the one on my 78 Ford F 150. Seriously.
     
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  13. MOSS

    MOSS Formula 3
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  14. raysur

    raysur Formula Junior

    May 3, 2008
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    Jeff
    I'm going to the auto parts store now to check those out. Thanks!

    Worst case I'll hide a modern unit in my oem. I don't feel comfortable buying a used vacuum canister just to stay original.
     
  15. pshoejberg

    pshoejberg Formula 3
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    Dec 22, 2007
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    Worst case I'll hide a modern unit in my oem. I don't feel comfortable buying a used vacuum canister just to stay original.[/QUOTE]

    That might be a statement you will regret in a few years. Stay original at any "manageable risk" is my advise. In a few years you could be digging holes in the ground searching for the correct canister. Your own unit is definitely toast and will never be operational again in my opinion.

    Best regards

    Peter
     

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