Differential Hub Problem | FerrariChat

Differential Hub Problem

Discussion in '308/328' started by skipgt4, Jul 25, 2021.

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  1. skipgt4

    skipgt4 Formula Junior

    Nov 3, 2003
    446
    GR Michigan
    Full Name:
    Charles VDB
    i am working on my 1978 308 GTS
    While I had the drive shafts out to replace the CV Joints I thought I would do the differential seals at the same time.

    The bolts for the differential hubs came out nicely with the impact gun. The hubs themselves I can not get to move at all. I cleaned up the bolts and got a better look at the hub and it looks like this job may have been done before. It looks like the hubs and bolts were sealed with white silicone calking. At this point I am not positive the seals are leaking I was just going to replace them while I was in there. One of the CV Boots was torn so I can’t be sure what came from the joint and what might have come from the seal.

    Anyone have a good idea on how to get the hub off (break down the silicone calk)?

    Should I clean everything up and put it all back together so I can tell if the differential seal is really leaking?

    Is there another way to tell if the seal is leaking other than driving the car?
     
  2. skipgt4

    skipgt4 Formula Junior

    Nov 3, 2003
    446
    GR Michigan
    Full Name:
    Charles VDB
    Maybe someone that has done this job before could chime in. Does the hub/flange just slide off the spline differential shaft with a little effort or do you need a gear puller?


    Sent from my iPhone using FerrariChat
     
  3. smg2

    smg2 F1 World Champ
    Sponsor

    Apr 1, 2004
    16,338
    Dumpster Fire #31
    Full Name:
    SMG
    I've had some give me trouble. It's a splined shaft, nothing to really hold it in place. Puller should not be needed but if a prior grease monkey packed silicone in there it'll make removal a pita, and a puller could help get it loose. I don't use silicone as the splined shaft is hollow, that bolt hole goes all the way to the diff clutch plates. Use anerobic sealant instead.

    Once apart, clean the inner splines completely. Factory sealant leaves a hardened film behind that also gets in the way. I chip it out with a pick then follow with a wire brush.
     
    waymar likes this.
  4. smg2

    smg2 F1 World Champ
    Sponsor

    Apr 1, 2004
    16,338
    Dumpster Fire #31
    Full Name:
    SMG
    thorn and waymar like this.
  5. skipgt4

    skipgt4 Formula Junior

    Nov 3, 2003
    446
    GR Michigan
    Full Name:
    Charles VDB
    Thank you
    Very helpful to know there is nothing else in there that might be holding the hub in place.


    Sent from my iPhone using FerrariChat
     
  6. bl10

    bl10 Formula Junior

    Jun 8, 2011
    442
    Chatsworth, CA
    Full Name:
    Barry Leavengood
  7. jgmblair

    jgmblair Formula Junior
    Silver Subscribed

    May 27, 2010
    814
    Winnipeg, MB Canada
    Full Name:
    Jeff Blair
    Look at my thread 1977 308 GTB 21921 the last few pictures will show the parts. It was suggested in my thread to silicone the splines on the hub which I did not do nor think it’s necessary. The purpose of the surface area of the washer is to ensure, with the appropriate amount of sealant, a proper seal.
     
  8. skipgt4

    skipgt4 Formula Junior

    Nov 3, 2003
    446
    GR Michigan
    Full Name:
    Charles VDB
    Not a dumb question, but yes I did. I ended up using a three ear puller. they were both pretty stuck but they did come off in the end.
     

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