355 - Pumpkin internal leak source | FerrariChat

355 Pumpkin internal leak source

Discussion in '348/355' started by Carmellini, Oct 24, 2024.

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  1. Carmellini

    Carmellini Formula Junior

    Jul 16, 2019
    964
    Removed clutch pumpkin and inside was very moist and black. Looks like gear oil mixed with clutch plate dust.

    Left the housing on workbench overnight and a large puddle of gear oil about the size of a golf ball was at the center. First guess is triple seal leak, but would like to know what other seals/o rings etc. are present for gear oil to leak out?
     
  2. Ferrarium

    Ferrarium F1 Veteran
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    Jul 28, 2018
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    Eric
    Triple seals, then there is the ton itself, it has a seal. Few prongs in there but behind various plates. Trip seals is the prime culprit. Voith is filled with grease and it can get clutch fluid in it, liquify and sling grease. I’d bet clutch plates are coated and flywheel likely has hot spots. Definitely take it all down.
     
  3. jjtjr

    jjtjr Formula Junior

    Aug 29, 2016
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    john truskowski
    Also worth mentioning, when you do the triple seals dont forget to take the covers off (next to the throwout bearing) and seal them as well.
     
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  4. Carmellini

    Carmellini Formula Junior

    Jul 16, 2019
    964
    Jan 2021: throw out bearing failure led to replacement with Hill Engineering upgrade and viton triple seals. Clutch looked very good with 40k on odo.

    Today @ 49k miles, clutch has been slipping for near a year and finally tired of driving gingerly. Disc "looks" good, but measures at 6.75 which I think is end of life?

    Yes, both flywheel and pressure plate have hot spots

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    Agreed and the sting comes from the sloppy install I did back in 2021. What did I do wrong? Certain to do more research so this doesn't happen again. Any tips appreciated.

    Proceeding with caution to make sure there are not other sources of leakage. Definitely feels and smells of gear oil and not brake fluid, but I don't like the look of the TOB.

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    TOB is wet mostly on the lower side. Hoping this is just how fluid go slung around?

    Back to triple seals: my plan is to reinstall the viton unless the OEM is the better way to go?
     
  5. Carmellini

    Carmellini Formula Junior

    Jul 16, 2019
    964
    \

    Yes, I think I did these back in 2021, but will do again since I can't be certain. Thanks.
     
  6. Ferrarium

    Ferrarium F1 Veteran
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    When those seals leak it slings everywhere and crawls up everything. I would suspect it got into the Voith, there are O-rings in there to prevent it but no one ever replaces them so they are probably 30 years old and barley seal anymore. The grease goes in white but comes out black and that looks a bit like grease with clutch fluid mixture residue on the TOB. I assume you cleaned a lot up.
     
  7. Rifledriver

    Rifledriver Three Time F1 World Champ

    Apr 29, 2004
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    Brian Crall
    Triple seal leak only leaks oil into the flywheel. Those leaks are from a different source. Probably the clutch shaft seal. If the clutch is wet, thats it.
     
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  8. Carmellini

    Carmellini Formula Junior

    Jul 16, 2019
    964
    I have intentionally NOT cleaned up anything. Does that provide any useful information?

    Not sure I understand "into the flywheel?" Does that mean directly into the voith only? Pretty sure the triple seals
    are a fault and turning the pumpkin clutch side up overnight left that small puddle of gear oil,

    Are you referring to the o-ring just forward of the triple seals?

    The clutch is dirty and looks somewhat moist, but I would not say wet.
     
  9. Targatime

    Targatime Formula 3

    Feb 22, 2014
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    Los Angeles
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  10. Ferrarium

    Ferrarium F1 Veteran
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    This may help if you have not seen it. It would advise if you remove those bolts that mount the flywheel to the damper, they stretch. So if you don’t have new bolts, you wanna take a grinder and grind them down half a millimeter or so then chamber the edge or else they can and probably will damage the voith housing and ruin it. I seem to recall that at least.

     
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  11. Carmellini

    Carmellini Formula Junior

    Jul 16, 2019
    964
    ...and the fun begins......I bought a high quality blind hold puller that grabs the first bearing on the front of the flywheel very well,
    but with slide hammer not able to get it to budge.

    I could rig up a set up to reverse press the bearing, but I worry about putting pressure down on the flywheel which I am thinking
    might deform the upper voith cover? Ideas?
     
  12. yelcab

    yelcab F1 World Champ
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    Nov 29, 2001
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    Mitchell Le
  13. yelcab

    yelcab F1 World Champ
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    Mitchell Le
  14. Carmellini

    Carmellini Formula Junior

    Jul 16, 2019
    964
    ^^^^that's the exact puller I am using......lol. the thing won't budge. Later today will apply some heat.
     
  15. yelcab

    yelcab F1 World Champ
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    Mitchell Le
    I have never needed heat but there is always the first time. It is a press fit so if it does not come out, something is bad about the bearing or the hole where it fits in.
     
  16. Carmellini

    Carmellini Formula Junior

    Jul 16, 2019
    964
    I will be replacing with Hill Engineering flywheel, so if all else fails I guess I can cut it out?
     
  17. Ricambi America

    Ricambi America F1 World Champ
    Sponsor Owner

    NO. The Hill Engineering flywheels no longer include the bearing. Do not destroy the bearing.
     
  18. Carmellini

    Carmellini Formula Junior

    Jul 16, 2019
    964
    Daniel, I think I may have found a replacement for that bearing.......

    NTN 6006LHA1 is on the bearing, which is NLA from NTN. It has a light contact seal which NTN tech
    support tells me was used for CAFE regulations involving fuel economy. Viton on one side, butyl on the other.
    C3 internal clearance. Filled with standard grease. Rated at 120'C/250'F. 9,200 rpm.

    The most compatible bearing they make is 6006 LLUA1/C3 has a full contact seal, which is better for dust, viton on both sides, C3 clearance,
    standard grease, but rated at 7,700 rpm.

    Perhaps a slightly better option is

    SKF 6006-2RS2/C3 S0 GWP:
    2RS2: viton on both sides
    C3: internal cleanance
    S0: bearing rings/washers dimensionally stabilized for use at operating temps 150'C/302'F
    GWP: Klueber Asonic HQ 72-102 hi temp grease
    rated to 8.000.

    Would it be better to re use a 28 year old bearing with 9,200 rpm rating, or a new one with
    8,000 rating? Way above my pay grade.







    \
     
  19. Rifledriver

    Rifledriver Three Time F1 World Champ

    Apr 29, 2004
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    Bearings are out there. I just replaced a set 2 weeks ago. All 3 flywheel bearings are a phone call away.
     
  20. m.stojanovic

    m.stojanovic F1 Rookie
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    Dec 22, 2011
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    Miroljub Stojanovic
    This bearing is exposed to high rpm only if you rev the engine with the clutch disengaged. With the clutch engaged, its rpm is zero (except when the clutch is slipping when it rotates for the rpm difference due to slipping).
     
  21. Targatime

    Targatime Formula 3

    Feb 22, 2014
    1,449
    Los Angeles
    Based on what I see on youtube, that seems to be exactly what a great many owners do with their 355's...
     
  22. m.stojanovic

    m.stojanovic F1 Rookie
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    Dec 22, 2011
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    Well, if you limit your revving at the traffic light drag race start line to 8,000 rpm, the SKF will be fine.
     
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  23. Ferrarium

    Ferrarium F1 Veteran
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    Jul 28, 2018
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    I agree I found 2 when I did mine.
     
  24. Carmellini

    Carmellini Formula Junior

    Jul 16, 2019
    964
    The large bearing is easy to find, as is the 165539 6007 bearing, but would love to know where to find
    the NLA 6006 LHA1 which is not found in the parts manual. @Rifledriver @Ferrarium
     
  25. Ferrarium

    Ferrarium F1 Veteran
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    I sold my car and along with it all the parts of which there were 2 of them, I would have sent you one dang it. I believe I searched using the SKF part number from the old bearing and found them from a bearing supplier.
     
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