Outer CV joint with blued hot spots on the OD

Roy Wendell erwendell at mac.com
Fri Mar 21 08:43:03 PDT 2008

On Wednesday, March 19, 2008, at 07:50PM, "RICHARD KROL" <rlk501 at msn.com> wrote:
>99 A4 with 142K
>Left front axel outer CV joint had catastrophic failure @ 142K from driving with torn boot.  I pulled the right front axel to repack and found "blued" hot spots on the OD where the ball bearings run,  the ball bearings appear to be rough as well.  This axel was not making any noise, the boot was intact and the joint was full of grease.  If I repack this joint any guesses on how long it will run?


AFAIK this is normal. I'm pretty sure I've seen the exact same thing on every joint I've taken apart. Like most drive line parts, the metal is machined in it's annealed form and then heat treated to final hardness. The blue color you describe sounds like selective heat treatment of the ball races. I doubt seriously that it's gotten hot enough during normal operation to cause that discoloration without you noticing symptoms.

Can anyone else back me up on this?


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