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Pinion seal leak after FTBR install

Discussion in 'Driveline' started by Flea03, May 29, 2012.

  1. Flea03

    Flea03 New Member

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    FTBR install with 3:73 gears and FR diff cover. After this I went on the track and the pinion seal began to leak major. Installed a new seal and the same thing happened. This didn't happen on the street, only on the track. The pinion angle is correct, no vibrations or noise. The vent tube is clear. I was told to much heat and pressure at track speeds and need to install a expansion tank? Anyone had this issue?
     
  2. rezcobra

    rezcobra New Member Established Member

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    Could be from high mileage. After so many miles a groove wears in and even new seals will leak. Something to check. Sometimes it can wear in on the rear pinion flange when oil is low. Rear pinion flanges are "about" only 25 bucks from Ford Racing dealers. Might check that.
     
  3. DE07GT

    DE07GT New Member Established Member

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    Could be the same thing that happened on my car. The splines on the inside of the pinion flange were worn, allowing fluid to pass through and be thrown all over the place as the driveshaft rotated.
     
  4. earico

    earico Lake Bum Established Member

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    ^This

    The problem is that the new seal is not riding in the same groove on the yoke as the old one. If it's off a 32nd of an inch it will blow fluid everywhere. The reason for this on your car is probably from the pinion gear moving location with the 3.73 install. The backspacing is probably different on the pinion now compared to the 3.55s.

    Sometimes you can hand sand the groove out if it's not too deep. If it's a deep one you may need what's called a yoke saver. They can be had for around $20.
     
  5. Flea03

    Flea03 New Member

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    Thanks for the info. I will look at these ideas and hopefully find the issue
     
  6. earico

    earico Lake Bum Established Member

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    Pull the yoke. If you see a new groove that is next to the old one that is your problem. Or they may be so close together that they look like one big groove. If you post a pic I can tell you.

    It's amazing that the rubber in the seal can make such a groove in a piece of hardened steel. If you think about the RPMs and heat it is seeing it makes sense. Plus that seal has a clamping spring around the inside of it. That keeps constant pressure on the seal as the seal material itself begins to wear away.
     
  7. Flea03

    Flea03 New Member

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    Went out to look at these ideas and remembered the pinion is new. It doesn't have a worn place yet?
     
  8. hotcobra03

    hotcobra03 Active Member Established Member

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    it will leak out the pinion nut...a redi-sleeve from national isnt worth it being a new yoke is cheap...

    the seal could be defective or even the spring is missing...or damaged spring..

    the spring is inside the lip of seal and is what causes the groove in yoke


    the new pinion nut will have a seal/rubber ring..if i remember right
     
    Last edited: Jun 4, 2012
  9. earico

    earico Lake Bum Established Member

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    The pinion slides into the yoke. The seal rides on the yoke not the pinion.
     
  10. Flea03

    Flea03 New Member

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    That's right. I will check the yoke, flange and install a new seal. Thanks
     
    Last edited: Jun 4, 2012
  11. suaveflooder

    suaveflooder 500 hp grocery getter Established Member

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    Simple fix maybe. You might have the driveshaft in the wrong orientation. It will bolt up two ways to the diff. One way it will vibrate just a little, but enough to cause the seal to leak. It happened to me after I rebuilt my diff. My marks were cleaned off by the shop that did it, so I had to guess. If you didn't mark the driveshaft and re-bolt it the same way, it would cause it to leak. Mine did it on a brand new seal.
     

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