Heat marks on Birfs normal? (1 Viewer)

[-Spike-]

That second photo is what I expected to see. That is consistent with an induction hardening process. They stick a plug into the bore and heat the forging. The bearing surfaces are then hard cut to match the ball profile.

Looking at the end-on photo, I can see that the material is thin enough to have burned through to the OD. Good info to have.

It's definitely thin. Also, I was freaked out the first time I saw that discoloration, Tools R Us had to calm me down.

Even worse, this is about the 700th thread about it.

 

[Malleus]

Well, if the search function worked...

 

[-Spike-]

Weird, search works for me, got 10+ pages of crap.

I'd buy the hardening explanation. I don't know dick about metalurgy, sounds like you do.

 

[Malleus]

Well, I've seen some of it done...

 

[hj 60]

Clicking will not go away with fresh grease, replace or switch side and click is in reverse.

 

[cruiserdan]

<snip> common wisdom (@cruiserdan and @beno) is to buy aftermarket and save your money. <snip>.

I do not recall making such a recommendation (unless Jack Daniels was involved)....

 

[-Spike-]

I do not recall making such a recommendation (unless Jack Daniels was involved)....

You were probably talking about your wife's truck.

 

[cruiserdan]

 

[Rifleman]

I'd bet these are induction hardened

Malleus, you are correct, those burn marks are in fact a sign that the CV joint bell, where the balls ride have been induction hardened. Seeing as those balls are about a 62 on the Rockwell hardness C scale, if the races in the CV joint bell, and the cage their housed in were not all hardened the same amount, either one, or all of these items would fail quickly under load.

 

[LINUS]

Every factory birf that I have seen has those marks, including new from the dealer, ~$500ea ones.

Yep. I bought a pair from Dan & mine were that $$ range.

Both the original set coming out of my axle & that new pair had the induction electrode marks from heat treating.

 

[cruiserdan]

The new OEMs in my trail box have "blue balls" as well......

 

[hj 60]

I was trying to avoid this.

 

[Dave 2000]

Marks are from the machining process, also seen on my OE parts. The chips on the inner cage comes from binding balls.....oooer, in other words the clicking you hear.

Regards

Dave

 

[Golgo13]

Yep. Its heat treating, plain and simple. It is NOT from machining. If there were that much heat built up during machining, then there is a serious problem with that machining cell. It is localized to improve strength/durability in those areas where it is applied. Probably found an issue during initial testing or it may have been designed that way, it tough to know for sure.
Either way, it doesn't matter. All the good parts look like that and it has no detrimental effect.
Clean, regrease, swap sides, re-assemble.

 

[Tools R Us]

Oops, my post should have said manufacturing instead of machining, but doesn't really mater, they come from the factory that way.

 

[Dave 2000]

Oops, my post should have said manufacturing instead of machining, but doesn't really mater, they come from the factory that way.

Yes mine should have read the same, having said that I have seen milling machines leave hot spots on materials where it is thinner and less able to absorb hest.

Regards

Dave