Repacking 348 Rear wheel bearings.

Discussion in 'Technical Q&A' started by gidge348, Jun 17, 2009.

  1. gidge348

    gidge348 Formula Junior

    Dec 12, 2008
    339
    Perth West Australia
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    Ian Wood
    #1 gidge348, Jun 17, 2009
    Last edited by a moderator: Sep 7, 2017
    Last couple of times I took the 348 out I noticed a slight noise coming from the left rear.

    Stayed the same in acceleration and deceleration so could probably rule out gearbox (thank goodness), seemed to go away when turning right so sounded like a wheel bearing.
    I had looked at the bearings before and they looked like a “sealed for life” unit, but thought that since they were probably RS did not really matter if I stuffed them up pulling them apart.

    So I put one in the press and popped it apart, came apart very easily and I then found the reason for the noise. The grease had obviously been there since leaving the factory in 93 and was dry, rock hard and pushed well back from the balls. I finished taking them apart and cleaned them up expecting to see damage to the balls, races and seals but they all cleaned up perfectly, no scores, blueing or anything. :):):):):):)

    So just repacked the bearings with high temp bearing grease put them back together and bingo problem solved.

    I had taken the stake nut from the drive shaft to a CV repair shop and they matched it up (apparently a very common size as they had boxes of them). Cost $5 each.

    So total cost $10 plus a bit of grease and about 2 hours, bit better than the $1300au I was bracing myself for 2 new hub/wheel bearings.



    The procedure I used was:

    1. Jack up car and put on axel stands and remove wheels.

    2. Remove calliper and disk.

    3. Remove park brake shoes, (you can work around them but it easier with them out of the way.)

    4. Un-stake axel nut.

    5. Remove nut, (my rattle gun did not have the cohunes for this so had to use a breaker bar).

    6. Push the axel as far in as you can and then you can get in behind to undo the 4 hub mounting bolts.

    7. Remove hub, put in shop press and press centre out from the back.

    8. Use a brass/aluminium drift on the balls to pop the seals out.

    9. Clean thoroughly and repack with your favourite grease.

    10. When re-pressing back together DO NOT push fully home, leave say 1mm or so to go otherwise you will put too much preload on the bearing. If you leave a bit of a gap when you do up the stake nut this will pull it down and give the right preload.

    11. Reassemble with a new stake nut and you are good to go.
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  2. No Doubt

    No Doubt Five Time F1 World Champ
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    Fantastic write up and pictorial!



    The Brotherhood lives!
     
  3. No Doubt

    No Doubt Five Time F1 World Champ
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    Can you elaborate on these steps any, please?!
     
  4. PAP 348

    PAP 348 Moderator
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    Dec 10, 2005
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    Excellent work Ian!! :D:D
     
  5. gidge348

    gidge348 Formula Junior

    Dec 12, 2008
    339
    Perth West Australia
    Full Name:
    Ian Wood
    #5 gidge348, Jun 18, 2009
    Last edited by a moderator: Sep 7, 2017
    No Probs sorry did not take enough pics will have to try and explain.

    6. Push the axel as far in as you can and then you can get in behind to undo the 4 hub mounting bolts.

    When the stake nut is done up it pulls the flange of the CV Joint over the 4 hub mounting bolts and you cannot get a socket on them. At first I thought I had to undo the wish bones and remove the upright in order to get access to the bolts. I later worked out that by just taking off the stake nut and pushing the splined axel in with your thumb it got enough space behind to get a socket onto the bolts (that’s the really bad third picture)

    7. Remove hub put in shop press and press centre out from the back.

    Sorry don’t have a pic in the press but attached is a pic of the rear of the bearing notice the inner section of the assembly with the splined shaft this if the section to be pushed out. (My press is a crappy $50.00 Chinese one but did the job fine)

    8. Use a brass/aluminium drift on the balls to pop the seals out.

    Once you have the centre of the bearing out you will notice that one seal is internal and one is external, I find the safest way not to damage the seals is just to turn them over on a piece of clumped up rag and gently tap the bearing with a soft drift. This then pushes out the seal without damage.

    9. Clean thoroughly and repack with your favourite grease.

    I pulled the balls out of the plastic race and washed them all in kerosene along with the seals and the other parts some bits took a bit of scrubbing with an old tooth brush. I had some Valvoline bearing grease on the shelf so used that I am sure are much better products out there. I have been using this stuff on car and boat trailers & the loads on the back of the Ferrari are probably not as great as that.

    10. When re-pressing back together DO NOT push fully home, leave say 1mm or so to go otherwise you will put too much preload on the bearing. If you leave a bit of a gap when you do up the stake nut this will pull it down and give the right preload.

    The attached pic probably shows this, notice how the inner splined section is about maybe 1 mm lower than the outer face of the bearing. If you look at the previous post pic no 4 of the axel you will note that there is a small step (with silver “never seize” on it). As the stake nut is done up it will pull the inner section of the bearing down to the height of step and bingo correct pre load. If you don’t leave the gap you will soon know it the bearing will be locked up.

    11. Reassemble with a new stake nut and you are good to go.
    Just reverse the process to reassemble.
    Hope this all make sense.
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  6. Corsa308

    Corsa308 Formula Junior

    Apr 22, 2007
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    Sydney, Australia
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    Steve D
    Man! those bearings did need re-packing.
    Reckon you got to them just in time.
    I wonder what the service manual suggests or indeed if someone has never done them in the past as they should've.
    Maybe not.

    Steve
     
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  8. gidge348

    gidge348 Formula Junior

    Dec 12, 2008
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    Ian Wood
    The manual just says "take em off and throw them away" can't see the point in spending $1300 for the sake of some new grease and a little maintenance.
     
  9. Fred2

    Fred2 F1 Veteran
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    Jan 2, 2005
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    nj
    Did it fix the noise?
     
  10. gidge348

    gidge348 Formula Junior

    Dec 12, 2008
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    Perth West Australia
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    Ian Wood
    yep
     
  11. ernie

    ernie Two Time F1 World Champ
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    Ian,

    That is one nice write up my brother! $10 and a couple hours work is music to my ears. GREAT JOB!
     
  12. No Doubt

    No Doubt Five Time F1 World Champ
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    #11 No Doubt, Jun 18, 2009
    Last edited by a moderator: Sep 7, 2017
    Thank you! You rock! Applause! Fantastic write up.
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  13. AceMaster

    AceMaster Two Time F1 World Champ

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    Excellent description, explanation, and pics. Thanks for taking the time to post this....just another example of the excellence of this brotherhood.
     
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  15. tbakowsky

    tbakowsky F1 World Champ
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    Sep 18, 2002
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    When you buy the bearing from Ferrari..its a complete hub and bearing assembly. Bolt it in and away you go, All new parts.

    Not trying to bring you down...but I'll bet the noise will be back. Good write up BTW, and I hope it does indeed save you the money.
     
  16. gidge348

    gidge348 Formula Junior

    Dec 12, 2008
    339
    Perth West Australia
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    Ian Wood
    #14 gidge348, Jun 18, 2009
    Last edited: Jun 18, 2009
    You are probably right replacement is always the easiest option, but I went over the balls, races cages and seals and I was unable to find any problems. The only thing I found that was RS was the grease and that is all I replaced.

    Because these cars are getting on for 20 years old now I would probably recommend that anyone with the time and inclination just changes the grease as a service item BEFORE damage occurs.

    I will definitely keep an eye (& ear) on it and if it reoccurs I will post again.
     
  17. 348SStb

    348SStb F1 Rookie
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    Apr 9, 2004
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    Would this procedure be useful on/recommended for the 355?
     
  18. ernie

    ernie Two Time F1 World Champ
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    I don't see why not? If I'm not mistaken the later 348's are running the same rear sealed cv joints as the 355's.
     
  19. gidge348

    gidge348 Formula Junior

    Dec 12, 2008
    339
    Perth West Australia
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    Ian Wood
    I would say yes, particularly because the 355 has probably had the same grease in there for 10+ years and we tend to do limited mileage the grease does dry out.

    The bearings on the late 348 and 355 look the same but seem to have different part numbers.

    The price of them however is the same so I am guessing they are identical
     

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