CV Joint project

What does the gearbox/diff. oil look like and what is it's level? I would imagine the cockeyed seal in the flange is to keep CV joint grease out of the diff./gearbox and gear oil in the diff./gearbox assembly.

 

It sounds like the last time someone did the CV's on your car they never quite finished the job ...... I'm guessing based upon what I did ,, put all the bolts in and start winding them till they stop moving easily ........... THEN change to the torque wrench and tighten them all.
I can only guess that someone started tightening with the torque wrench and was distracted , forgot , fired from the job ..........who knows.

If the bolts were only finger tight then grease may have been leaking out between the CV and the pressed metal housing that holds the rubber boot or the flanges to the diff / axle.

I did put a tiny bead of sealant around the outer edge of the CV's when I mated them back up with the flanges and the housing to hold the rubber boots. I have not had a drop of grease come out and it has seen quite a lot of high speed running (100Mph +) for the short time it has been together.

I reused most of my bolts because they were straight and threads were in excellent condition. Some were replaced because they had to be cut off , , a few had been over tightened and the thread butressed.

In your case I'd go with new bolts , , they can handle tightening , , but they probably dont like being twisted back and forth under power and braking which is what would have happened if they were not torqued up.

As for the "seal" on the flange coming out of the diff dont panic there , , mine turned out to simply be some sealant. All you are trying to do there is keep CV grease from creeping up the spline between the flange and the diff output shaft.


Enjoy what may be the dirtiest job on a 308 : )

 

"Project du jour" is right Jim. I also did this project during my brake/suspension redo on the 328 last summer. Not sure if you're planning on replacing your CV bolts and nuts. Most of my bolts were ok, however, the socket heads on a few of them got chewed up coming out. The bolts are 12.9 PN strength M10 x 1.25 65mm (length under the head). Our usual parts folks have them for $5-6/each. Several online metric fastener suppliers have these for much cheaper, however, it's next to impossible to find the correct length. I ended up purchasing 70mm long bolts from http://www.aaametric.com/index.php?pr=Home_Page for $0.95/each and then had them cut to 65mm. No such luck finding the specialized lock nuts. I ended up buying the nuts for $3.75/ea from Mcann's.
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I was quite prepared to use nylock nuts if the originals did not survive , it turned out all but 3 were fine.
The "special" nuts are simply another way to make them vibration proof. I compared the originals to some nylocks and they actually had slightly less turns of full thread in them. The portion of the originals which is used to make them vibration proof wont be doing a whiole lot of adding to the strength of the nut.
I wouldnt buy deformed nuts as can be purchased because they tend to make both the nut and bolt a single use item no matter how careful you are.

 

Is it me or does it look like someone scooped the grease out and never repacked it? Is that what you mean? Not good. Did the body shop have to remove this axle to fix the fender?

Is the groove you describe in the wavy pattern on the face of the CV joint? If not, I'm not sure what you mean by a groove on there. If that is it, I would call the usual suspects and see how much a new one costs. If cheap, I'd get one. If not, I'd reuse it and make sure the CV joint is in the same orientation to make sure the seal is good. I might throw it in the lathe to reface it, but I certainly wouldn't be interested in taking very much off.

The bolt in the center of the flange comes off and the whole flange slides off of the differential stub. There's your seal on the outside of the flange. It doesn't sound like this seal is leaking, but you will probably want to replace this seal because you are in there. When the flange goes back on you need to RTV the end of the splines under the washer, the splines are a path for grear oil to get in to the CV joint making the grease a sloppy mess that will escape and get flung everywhere. The orange thing on the inside of the flange will be RTV, not a pre-manufactured seal.

If I'm right and the CV joint was not adequately greased I'd give serious thought to replacing it. The good news is that it is far more likely to die slowly giving you lots of noisy warning than to fail catastrophically (sp?), but you are here, it may have had a rough life, it's only $80.

And FWIW, I really like the BMW style CV boot over the Porsche style. The BMW syle has the boot and flange crimped together rather permanently and that interface does not leak. The clamped boot to flange that is our cars OEM always seems to weep and fling stuff. The OEM boot alone is cheaper, however, around $10 each and the BMW with flange is more like $30. I also used a very light smear of RTV on the surface between the boot flange and CV joint to keep this well sealed also. Theorectically you don't need it.

 

Jim, I think you make up excuses to get your hands dirty on that car!

 

Love that grease packing tool. Almost bought one one,wish I would of. I like the red grease also. Looked for it, could not find it anywhere. I saw it used on a previous thread. Also like how your circlips have the ears with the little holes for the circlip pliers. Mine have no ears or holes. Would have saved a lot of time had I had your type. Your project looks like it is coming along great. Have fun.

 

Big Congrats on a job well done! What kind of oil filter are you using?

 

That's a Baldwin oil filter.

What is the red grease?

 

How did you guys first determine the CVs were not worn out of spec?

 

Hi Jim,

Yup, that's pretty obvious - would definitely agree with you there!

What I'm asking is a bit different. Specifically, if you have the CV out and you're repacking it and cleaning it up then why do that without first determining whether the CV is out of spec and possibly worn out? In other words, why spend time making it pretty if the thing needs to be rebuilt? Putting a potentially worn CV back in the car seems like a lot of work for not much benefit.

There's a CV shop in Seattle here and they do various things to determine compliance with spec. If it's worn beyond spec then there's a range of repair options to put it right - everything from simply inserting new balls, to resurfacing the race where it may be worn, etc. When I've taken out CVs I've always taken them there for a health check because I don't have the equipment to test precisely for wear myself (beyond the obvious visual) - was just wondering what you might have done in this regard.

The CVs may be a fairly common Lobro part, common to other vehicles and therefore not so expensive to replace - at least, that would be ideal!

Thanks.

 

Interesting. What shop would that be?

 

If it were worn out, wouldn't it make noise while you were driving it?

 

Hi Eric,

I think it's called Drivelines Northwest or something similar - I'll have to check. I go by there (East Marginal Way) pretty frequently, though haven't been inside for a couple years now. They seem like straight forward guys.

 

If it's making noise then it's definitely worn out.

Even if the CV isn't making noise it can still be time to replace/rebuild. You'll feel it as a slight jerking motion when coming on and off the gas - can be quite annoying.

 

Ok , , this is what a dead CV joint looks like.

This CV had a torn boot and I guess it had been torn for a while , the underneath of the car was filthy , grease had been thrown everywhere long long ago ........ I guess the previous owner didnt know what had been going on under there.

The car actually drove pretty good with the only clue that something was amiss was an occasional incredibly loud noise like a dead bearing usually occuring during corners ....... there was no hard and fast rule as to when the noise would occur or even IF it would occur.

What I found was these lines , 2 lines per bearing groove worn into the outer race of the CV joint. The area around the grooves is polished as all grooves in the other CV were , this is most likely due to balls rotating over these surfaces for decades , probably quite normal for any 2 metal bearing surfaces with lubrication to do.

The damaged parts are visible in the grooves pointed out with my brilliantly drawn arrows. The grooves on the left are not very deep and can be just felt when rubbing your finger over them .......... they look worse than they are.
The grooves on the right are easier to spot and easier to feel , , again not very deep , only a few thousandths of an inch deep at the most.
Thats what a dead CV looks like as far as I understand it.

I did not see any identifyable damage to the CV balls and the inner of the CV was looking ok with only the very slightest marks in them but much larger areas polished and shiney.
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I dont think they wear out as such , , those inner surfaces are hardened and incredibly tough , , an obvious failure such as the lines I found is the only cause I have ever seen to replace them.
Come to think of it a place I saw selling CV's for dune buggies (exactly the same size as 930's and Ferrari's) in California offer CV's with greater flexability by installing smaller balls (0.020" from memory) with the standard inner and outer .......... therefore it would make sense that any uniform difference in clearance does not seem to spell impending disaster. It seems to be ruts or dents in one spot that cause all the trouble.

 

Good thread Jim, and informative posts Paul.

While my QV's engine is out took the opporunity to have the driver's side axle boot replaced.
Last week I took both axles to A-1 Driveshaft here in Milwaukee, and after checking they declared the passenger axle fine, but found the cage inside the driver's side axles, outside end, had a chuck the approximate size of a domino totally missing. At least 2 balls were not at all contained by the cage.
Neither axle was making noticeable noises under any driving condition.

Cost $75 to have that axle checked for straightness and rebuilt including new boots.

 

Once you get things apart and really get inside, you never know what you will find. One thing leads to another. I know how that goes,,,,, as long as we are in there ,,,,,,,,,,,, might as well fix ,,,,,,,,,,,,,,,,,.

 

Got any pics of the blue 328 sitting out in the sun? That color looks great!