308 driveshaft location | FerrariChat

308 driveshaft location

Discussion in 'Technical Q&A' started by Andrew McLaren, Aug 30, 2020.

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  1. Andrew McLaren

    Aug 21, 2020
    33
    Auckland
    Full Name:
    Andrew McLaren
    Hopefully not a dumb question, but....
    I'm just finishing replacing the rear suspension bushes, and while under the car (its just sitting on axle stands), noticed that the inboard driveshaft boot wasn't properly seated, so went ahead to do the obvious thing. With the suspension fully extended as it is at present, there is enough longitudinal play in the driveshaft splines for them to disengage from inside the CV's. This doesn't seem right, but I can't find any reference to what should prevent this happening. I am assuming there must be something (other than the boot) which prevents them disengaging?
    Thanks for any clarification!
    Andrew
     
  2. Steve Magnusson

    Steve Magnusson Two Time F1 World Champ
    Lifetime Rossa

    Jan 11, 2001
    24,997
    30°30'40" N 97°35'41" W (Texas)
    Full Name:
    Steve Magnusson
    Do you have the coil-over shock absorber installed? Without it in place, the suspension will droop further than is possible when it is present.
     
  3. Andrew McLaren

    Aug 21, 2020
    33
    Auckland
    Full Name:
    Andrew McLaren
    Everything is installed, and the shocks were never removed. The suspension is now at the maximum extension (or droop as you call it), and the drive shaft can definitely come out far enough to disengage.

    I've been trying to find an explosion of the driveshaft/CV assembly, but the Ferrari parts book I have (78 US spec 308 - mine is a 79 US spec) shows only a complete driveshaft/CV assembly in its table 30. From the drawing of the complete driveshaft, it shows a circlip at the inboard side of the splines, which would definitely stop the shaft retracting right out. However, its impossible to know which end of the driveshaft is shown (or are these reversible?). If both ends should have something like this, lack of one would definitely explain what I am seeing.

    Regards

    Andrew
     
  4. Andrew McLaren

    Aug 21, 2020
    33
    Auckland
    Full Name:
    Andrew McLaren
    I think I'm getting closer.

    Just been reading through http://www.birdman308.com/service/cv_joints/cv_joint.htm - this definitely refers to circlips inboard of the CV's, and I'm guessing one of mine has come off (which probably means it was never seated right). I'll look at pulling the driveshaft to have a look - hopefully there is no other damage.
     
  5. theunissenguido

    theunissenguido Formula 3
    Owner Silver Subscribed

    Jan 21, 2004
    2,367
    Argent/Brasil
    Full Name:
    Guido
    That circlips should be made of steel, but I also see them of softer iron, so they can come loose. Make shure to press them around the axle.
     
  6. Andrew McLaren

    Aug 21, 2020
    33
    Auckland
    Full Name:
    Andrew McLaren
    Mystery solved. Got the halfshaft out today (not as difficult to undo as the birdman site implied, but it had been off to do the boots a few years ago, so nothing seized). Shaft came out, then out dropped an intact (phew) circlip. No signs on it that it has been banging around in there, and everything clean, well greased, and intact. I'm guessing that the circlip was not seated correctly when the boots were done (not by me!) and I probably jarred it getting the suspension arms back on, which was enough to dislodge it. Circlip also measures a tad bigger diameter than the slot, so even seated would have been loose. It should never have been reused. I'll chase up new circlips tomorrow, and put it back together. This had the potential to be disastrous!
     
    theunissenguido likes this.
  7. Andrew McLaren

    Aug 21, 2020
    33
    Auckland
    Full Name:
    Andrew McLaren
    While I don't have any boot issues, I'm thinking while I'm in this deep I may as well clean out the cc'd and repack them before I reassemble them all (with NEW circlips!). Ferrari specify 140g of Molykote BR2 for each CV, but that doesn't appear to be available here in NZ.
    The kits Birdman referred to on the rebuild notes above appears to use 100g per joint of what I'm guessing is Liqui Moly, I'm guessing LM2003 - also not available here!
    So what are people using, both brands and quantities? From a quick search around the web, there are a lot of cheapo semi branded stuff I'll avoid, but the two I came up with was a Penrite CV joint grease, and Redline CV2, which are both designed for CV units. The expectation seems to be around 100g per unit.
    Or because everything is so intact, should I just replace the clips and be done with it?
     
  8. thorn

    thorn F1 Rookie
    Silver Subscribed

    Aug 7, 2012
    3,322
    Tallahassee, FL
    I'd just replace the clip.
     
  9. Andrew McLaren

    Aug 21, 2020
    33
    Auckland
    Full Name:
    Andrew McLaren
    I had a good look at these, and plenty of grease and no contamination, so just ended up replacing the circlip. The circlip at the other end was seated correctly, but quite soft, so replaced that as well. All reassembled and back running. Thanks for the help and advice.
    Andrew
     
    thorn likes this.

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