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Shift Shaft Seals Procedure Clarity?

Discussion in 'Mondial' started by moysiuan, Dec 22, 2019.

  1. Rifledriver

    Rifledriver Two Time F1 World Champ

    Apr 29, 2004
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    Brian Crall
    #51 Rifledriver, Jan 7, 2020
    Last edited: Jan 7, 2020

    The cup seal seals on its OD, and its ID in exactly the same way the same design seal works in a brake cylinder. In my opinion since it is an asymmetrical seal sealing liquids on both sides from each other and neither side has appreciable pressure involved it makes no difference which way it is installed in the middle position. I have seen them installed both ways and never noticed any difference in its performance. .The forward seal on the other hand has a definite correct way.
     
  2. Rifledriver

    Rifledriver Two Time F1 World Champ

    Apr 29, 2004
    26,461
    Austin TX
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    Brian Crall
    #52 Rifledriver, Jan 7, 2020
    Last edited: Jan 7, 2020
    As one who has done this against time and been rated for time based performance every day of my professional life for several decades I disagree completely. Dropping another pan with the associated parts, clean up of the gasket surfaces, reinstalling of the pan and being liable for yet another potential trouble area there simply is no valid discussion as to which method is superior. That was proven decades ago by professionals yet here for some reason it is still open to debate by people who do it once or twice in their lives.
     
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  3. AndruL

    AndruL Karting

    Apr 4, 2018
    174
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    AndruL
    I just did mine a couple of months ago and can confirm that the seal in the gearbox in my car had the cup side facing in the same direction as the other seal, toward the rear of the car.
     
  4. moysiuan

    moysiuan Formula 3
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    Nov 1, 2005
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    Andy
    Well I certainly agree. The job is hard enough to do while on jack stands, hanging around under there longer than necessary doesn't really appeal to me.

    I think the need for the pan off relates to 308 people using the Verrel quad seals which apparently are not as flexible as the factory cup seal, and maybe can't be shoved in the small hole in the gearbox side. But in any event given my original cup seals lasted 31 years before weeping, there was no case to use a non factory seal option.

    In my case the gaskets on the pans were installed dry, the old gasket on the gear pan just fell away, and the surfaces are clean, I presume the oil pan would be like that too. Some threads say to use sealer, others to go dry for the reason of future disassembly. Since my gaskets originally sealed dry just fine, I won't be using sealer, maybe just a dab of hylomar around the studs to keep the gasket in place and prevent the stud weeping many seem to experience.

    Thank you for the comfort of mind regarding the cup seal direction. Can't really see how the direction of the cup would matter, both sides need to be sealed, and with a crankcase ventilated car, the pressure in the oil sump would be very low if not ambient pressue like the gearbox. Given the shift shaft moves back and forth, the seal has to seal under this type of motion in either direction, so reversing the seal wouldn't seem to change anything relating to the forces being dealt with. Also given the original predecessor omnidirectional O ring approach, the cup seal looks like it is simply offering a broader sealing and wear surface, probably offered a longer service life.
     
  5. theunissenguido

    theunissenguido Formula 3
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    Jan 21, 2004
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    Guido
    Make shure the bolt that hold the lever on the shaft is fast enough....otherwise you risk the lever coming loose when driving.
    Guido
     
  6. Rifledriver

    Rifledriver Two Time F1 World Champ

    Apr 29, 2004
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    You are very lucky. Those old gaskets had a habit, when installed dry adhering to the case like epoxy. I have had some that nearly needed to be chiseled off. Great fun removing old rock hard asbestos gaskets around all those studs.
     
  7. conan

    conan Formula Junior

    Nov 13, 2011
    290
    Yes, tell me about it .. the intake gasket had to be carefully scraped off, took me several hours. I found the Loctite 7200 very helpful in softening the old black gasket. The newer green gaskets were extremely easy to remove using the 7200 on it. The remaining greenish sealant still stuck to the flange just crimpled and could be wiped off.
     
  8. moysiuan

    moysiuan Formula 3
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    Andy
    I do note the nut was a nyloc item, those often don't hold well on reuse, so I used some loctite. Fyi, this nut is a fine thread rather than course thread, there are none in metric at my local supply stores like that. Otherwise would have used a fresh nyloc nut.
     
  9. Rifledriver

    Rifledriver Two Time F1 World Champ

    Apr 29, 2004
    26,461
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    Brian Crall
    I think he was referring to the internal bolt that pinches the selector to the shaft. That one is an 8 x 1.25 by about 25-30mm long with a lock washer and no nut.
     
    theunissenguido likes this.
  10. moysiuan

    moysiuan Formula 3
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    Ah, yes, I used a new lock washer on that one and torqued to 20lbs which seemed about tight enough.

    (I was referring to the silent block joint with the nyloc nut).
     

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