Flange Wear from CV Joint Options

[frank_c]

Today I started the process of dropping the engine & transmission so that I can send the transmission off to Dr. Evil and take care of some misc engine work (rear main seal, oil return tubes, etc. ). As part of this work I was also hunting for a clunking noise I hear from the back when the car is stopped and as I let the clutch out and the car just starts rolling forward. I already checked and/or replaced all suspension and engine mounts, as well as the outer CV joint bolts (inners are safety wired) and found nothing loose. So next on my list was either the CV joints themselves, or possibly loose flywheel bolts.

When I removed the inner CV joints from the transaxle flanges, I was surprised to see some pretty deep gouges in the flanges from the CV joint inner race/star (see photos below). This seems like a good candidate for the noise I am hearing.

I have never seen this type of wear before with any of the other cars I've worked on - what would cause this? I noticed that there is not much grease in the joints, which I suppose is one possibility. Was the inner race put on backwards? Wrong parts? I did confirm that the axle shaft does move in and out freely at the outer CV joint.

Thanks for any insight.

Left flange:


Right flange:


Circled area shows where inner race is cutting into the flange.

[Superhawk996]

“ Observation 1:
The inner conical washer has grooves worn in it from the CV balls (see photo). Maybe this is considered normal wear, but I have never seen this before on any of the Porsches and BMWs I've worked on. This seems to fall into the "axles shafts too long" bucket.”

The joint is clearly hyper-extending.

I’m not trying to be a dick to any of the others that have posted, they are all good guys and have been playing with 914s for years . . . but go with your gut. Regardless of what anyone is saying they have seen, or have rarely it may be, it isn’t normal and it isn’t that way by design. I say that as an automotive engineer with 27 years experience in the industry. No one would design or build a CV that is going to create metal debris inside the CV from interference between the CV and the flange. It’s really that simple.

Having seen these marks before is like me saying I’ve seen spun main or rod bearings in a stock engine. Just because it has been observed before, and it’s rare, doesn’t make it normal or correct.

You’re going to have to disassemble and potentially measure to figure out root cause. Definitely have to replace as those joints are trashed by the debris on top of whatever caused the contact in the first place.


To reiterate:
Something is drastically wrong - apologize I can’t pinpoint what it is.
GKN / Lobro are quality joints but need to be correct joint for application.
PMB is a reputable supplier. Contact them for parts when you get to that point.