CV joint

Discussion in 'Mech Tech' started by Uncle Nick, Jul 6, 2019.

  1. Hi all, I replaced my first cv boot today, what a messy job! There must be an easier way or better design.
    Anyway, I checked the other end while the shaft was off and found this damage/wear.
    So, is it knackered and needs replacing and how do you check them without removing the shaft?
    Cheers in advance.
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  2. That joint component has been dropped hence the chipped metal, probably before assembly into a parts bin. It was used because the chip doesnt affect any bearing surface.

    The surfaces that actually transmit the drive look pretty good.. When they wear they develop wear shiny "valleys" in the channels where the ball bearings roll. Your pictures still seem to have the machining marks visible over the whole surface.

    An easy way to check is to try turning the driveshaft by hand, while holding the outside of the CV joint stationary. If it can turn more than a few degrees its wearing. If one turns a lot more than the rest its almost certainly knackered. Flipping the driveshaft so the ends are being driven the other way buys you time.

    Dont forget to check when you reassemble the joint to line up the inside and outside of the joint so that big gap faces little gap allowing articulation. Doing it the other way will make the joint unable to flex properly, leading to total failure in a few miles ( it depends on the angle the driveshaft makes with the CV joints.. if its pretty straight it can be enough to get you to e.g. Ashford in Kent en route to the ferry. Then it totally breaks.) So do it right and check its flexi..;)
     
    Uncle Nick likes this.
  3. Thanks for the reply.

    I'm reasonably sure the bearing at other end flexes ok. So you think this one is ok to re-use?
     
  4. Based on the pictures , yes.

    They dont break just get noisy with wear if they are put together with enough grease and the balls in the grooves the right way.

    The only way to break them is either misassemble or manage to pop the rear spring plates past the lower bump stops taking big air which pulls hard on the driveshaft via the CV joints (like the Hasta Alaska person over on the Samba), which pulls the balls out of the joint, then they spin.

    Far more people fail to torque the bolts, or forget Schnorr washers and spacer plates so that the CV joints just drop off.
     
    Uncle Nick likes this.
  5. There’s no lock washers so I may get some, especially as one of the bolts had already dropped out and the others seemed only slightly more than finger tight.
    Thanks for all your help, saved me replacing this one.
     
  6. You need the serrated cone washers and the spreader plates, otherwise the bolts may come undone. With everything in place, they’ll stay put.
     
    Uncle Nick likes this.
  7. As it has been said, torque up instead of congratulating yourself on a record time job, only for about 500 miles later, clattery bang bang. I know this.
     
    Uncle Nick likes this.
  8. And you can get the 12.9 m8 high tensile bolts and lock washers in bag full quantities from UK suppliers for the price of a hand full of scene tax bolts. Worth replacing all 24 anyway as then the heads will not be chewed and rusty.
     
    Uncle Nick likes this.
  9. mcswiggs and Uncle Nick like this.
  10. Cheers Jules, hadn’t heard of them before but ordered and here in record time.
    Just got to finish rebuilding the joints and fitting the boots now!
     
    nicktuft likes this.
  11. Dont forget to get the luvvely new scene tax boots... Only £141 a set of four.. o_O:worship: 20180627_124953.jpg
     

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  12. Damn missed them! Just got the cheap and nasty versions from JK.

    BTW, do you happen to know what the correct torque figure is for the bolts?

    I’ve found via google a figure of 25-30 ft.lbs, does that seem right?
     
    Last edited: Jul 12, 2019

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