CV Joint - Reading wear and Rebuilding Questions

[Tom '74 911]

Hi -

First, I must say that CV joint grease is the stickiest, nastiest goop I've worked with! I've just finished taking apart and cleaning my CV Joints and was wondering how much wear is too much? All 4 seem to be in generally good shape with basically no pitting anywhere. Two are showing a bit more wear than the others - see pics below - and while I'm inclined to rebuild them w/new grease and run them as is, I thought I'd just check as I've never done CV maintenance before. The pics are from the worst one of the bunch.

Also, My car is a '74 911 and the CVs each have 4-bolts w/2 pins. I'd like to replace the outer protection cap (the piece that the large end of the boot is connected to) along with the boot itself. I see in the Pelican catalog that you can buy them together as a single unit; see: Porsche 911 & Carrera Axles & Bearings - Page 1

These are listed for mid-'75 to '84 cars and the photo looks like the caps are for 6-bolt joints. So my question for those in the know is can I use these on my CVs w/only 4-bolts? Also, did the change from 4-bolt CVs to 6-bolt CVs happen mid-'75?

Thanks,
Tom

[Tom '74 911]

Bump for Monday AM.
Thanks,
Tom

[sjf911]

They are a sticky mess to deal with. I don't know how you measure the wear in these things, those look like normal wear marks. I had actual scoring on my bearing surfaces where the ball had actually worn through the hardened surface layer. The interesting thing was that I didn't even know I had a problem. I had my shafts off to do a suspension refresh and when I went to reinstall the right hand shaft it was binding so I had to disassemble it. Here is what it looked like:

[myamoto1]

Tom - you probably don't need to replace yours just yet, but it may be something worth doing since you already have it apart. Once you get scoring like Steve has, you'll definitely want to replace.

I recently replaced 2 of mine (scoring like Steve's) and the difference between the old vs new was amazing. The new ones made my old ones feel like wet spaghetti.. I now wish I had replaced all 4. The good news is, it's not that hard to do, so when I finally get around to my rear suspension refresh, I'll be getting 2 more new CVs.

[RWebb]

IIRC, that is technically called spalling - likely a wiki on that

Since you enjoyed the labor so much, how would you like to do it all over again fairly soon??
I'd replace the both units - Think about an upgrade - Grady posted somewhere on the best CVs (so I guess it would be an UpGrady...). BUT it may require a bunch of fabbing/mods/etc.

[RWebb]

PS - I'd like to see the mileage on both of you guys' CV joints if you can post that & what maint. they got as far as you know...

[Tom '74 911]

Originally Posted by RWebb

Since you enjoyed the labor so much, how would you like to do it all over again fairly soon??
I'd replace the both units - Think about an upgrade - Grady posted somewhere on the best CVs (so I guess it would be an UpGrady...). BUT it may require a bunch of fabbing/mods/etc.

This is not something I'd like to do on an annual basis, however my plans include upgrading my engine and transmission in the not-to-distant future, so I'd like to not spend $600 on new axels and CV joints for my '74 915, only to upgrade to a later 915 in a year or two and have to do it all over again. Springing for grease, gaskets, boots etc... - maybe $50-60 total? - no problem. While it's not my favorite way to pass time, my labor IS free.

Upgrading what I have may be an option, but my guess is that it would require upgrading the flanges on the trans. and trailing arm too - probably more than I want to bite off at the moment. I skimmed through the ultimate CV joint thread:

Reconstructing Constant Velocity (CV) Joints

only enough to realize that's it's not as simple as just swapping flanges around.

Just trying to stretch out the life of what I have and not throw dollar bills out the window, as long as it's a safe and somewhat rational option.

Tom

[Tom '74 911]

Originally Posted by RWebb

PS - I'd like to see the mileage on both of you guys' CV joints if you can post that & what maint. they got as far as you know...

No idea on milage. They have been rebuilt at some point as the boots don't match between the 2 sides, but I don't know when. They were performing just fine as far as I could tell. The grease looked a little lumpy and older and my motor is currently out so. . . one of the "while you're in there" things.

Tom

[Tom '74 911]

Hello,
I'd like to bump this with a question. I'm getting ready to reassemble these things and have a question on the orientation of the "cage" piece (shown in photos 5 & 6 in my first post).

I have some instructions (Bentley?) that clearly state the orientation of the piece with the "splined flange" (that the axle fits into) and the orientation of the outer piece. It does not, however mention anything about the "cage" orientation. There is clearly a bigger chamfer on the inside lip of one side. Does it matter if it faces in, towards the axle, or out?

Thanks,
Tom

[James Brown]

"galling
(1) a condition whereby excessive friction between mating parts results in localized welding; subsequent spalling and a further roughening of the rubbing surfaces may follow; (2) a severe form of scuffing associated with gross damage to the surfaces or failure."

from some definition I found on the web so you know it's correct. Tom, you can flip or reverse your joints to get even wear (R for L).