CV joints project...I want to share my findings

[Zef]

I just removed my both axle shaft for the CV joints winter project...There was no noise coming from them but after 23 years, I wanted to give a look there.The bolts are in perfect condition and the boot have no cracks.I found that both inner boot end on both axle has no clamps installed...So the dirty !"/$%? was allowed to go in...What do you think about that...!!! And I found that the holding screws on the stub were loose and one was broken...I will open the CV joints tomorrow and will replace the screws as well...Syl

[dentist90]

I'm at the same point, too. My boots weren't clamped on either, not even zip straps. Looks ok, though. I left my stub axles on the car, just took out the axle and CV's. I have a couple of questions about reinstalling:
1) are they reversible, left to right? They look symmetrical to me
2) does it make sense to reverse them on reinstallation to even the wear on the internal surfaces?

[dentist90]

I left my car like this for the winter.... wheels still attached.

[Jim Sims]

"And I found that the holding screws on the stub were loose and one was broken"

Looks like someone may have had the brake rotors off sometime in the past and a corroded flat head screw broke in the process of removal; you may find the remnant of the screw thoroughly rusted into the threaded hole. These screws keep the rotor in place when the wheel is removed. Other times they see little or no load as the hub studs and wheel lug nuts clamp the whole assembly together when the lug nuts are tightened.

[randywebb]

"23 years"

- I would remove the old grease and put in new grease every 5 years.

Search up the fine & comprehensive CV joint renewal thread that Randy Cale did. Use Grady and recale to add to the search terms.

[rcecale]

Here's the thread Randy mentioned.

Just to clarify...all I did was ask a lot of questions. Grady Clay and several others are the real sources of knowledge.

Randy

[Zef]

Wow..what a big thread. I will read it before to disassemble my CV joints. Thanks a lot.

[Hugh R]

Ready Grady's instructions on putting the bolts back in and follow them to the letter! He knows of what he speaks (err, writes).

[Hugh R]

Randy,

Happy B-day Marine, Semper Fi!

[randywebb]

"all I did was ask a lot of questions"

Unnnnh -- not so fast. Monsieur Cale used to do maintenance on military jets (USMC). So it isn't just some guy off the streets* asking the questions.


* Ok, a little recruiting joke for the belated B-day party.

[Nine9six]

Originally posted by dentist90
I'm at the same point, too. My boots weren't clamped on either, not even zip straps. Looks ok, though. I left my stub axles on the car, just took out the axle and CV's. I have a couple of questions about reinstalling:
1) are they reversible, left to right? They look symmetrical to me
2) does it make sense to reverse them on reinstallation to even the wear on the internal surfaces?

I am not sure of the validity of this response, but I read where they can and should be swapped to extend the life and mileage of the constant velocity joints.

[rcecale]

And a motivated happy Birthday to you too, Hugh! This is still my favorite time of year. Of course it helps that my wife and I have our weeding anniversary on Nov. 10th as well, so we always have a place to go and celebrate.

And Mr. Webb, it's true I've turned many a wrench on Hornets and Phantoms in my 20 years of the Corps. I'm certainly at home inside a toolbox.

Working on these cars, though, is another story. Fortunately we've got the likes of Grady, John Walker and yes, even you, for guidance when we don't really know what we're doing.

Randy

[Walt Fricke]

Holding screws (rotor to hub) - don't worry about them. They are nice to have, but not essential. I ran for some years without one of them because I couldn't find the right replacement - that kind of bevel headed screw with a flat head in the right metric size. The 94 mas o menos pounds/feet of torque on each of the five wheel studs will take care of holding it in place.

Lack of a clamp on the boot - don't worry about that either, if it is what I think you think you lack. Your boots look like the kind that are crimped onto the metal flange through which the bolts are inserted. So the CV side is sealed (some types of boots slip over the flange, and so require a tight clamp - more than a zip tie can usually provide). But that wasn't your question.

The rubber of the boot itself is (usually) tight enough around the axle, assuming you don't take the car swimming. But you could always add a zip tie after you reassemble things if it makes you feel better. Famed race engineer Carroll Smith (RIP) liked to put a piece of plastic tubing (like from a brake cleaner can - the red extension) under the axle side lip and then zip the lip. He reasoned that you wanted any heated air inside to get out (and then get back in when cooled, and the tube would allow this and be long enough that nothing bad could get in. Anyway, the photos don't suggest that a) all your grease escaped so you had dry bearings, or b) a bunch of sand and gravel got into the CV from outside. Or even that moisture did. But they are just photos.

The moment of truth with CVs comes when you have them apart and clean enough to inspect the races (assuming, as appears to be the case, that the cage isn't broken). If they have palpable (literally - run your finger over the races where they are shiny to see if you feel any depth change from the unworn part) wear, time to change.

Though if you really really want to economize you could try reversing things (assuming you deem the grooving to be real but not too deep) by installing with the outside of the CV now facing in so the balls would want to wear on the unworn parts of the races (unless they are right in the center of the races). If so, you want to mark the parts carefully so you know which way things went on reassembly.

Otherwise, other than putting the same races, balls, and cages back together I don't think it matters a whit which ball goes in which race, or which way which race faces. The outers tend to have a circumferential groove, which can help you orient things if you think that matters.

Sometimes folks reverse the CVs - inner goes to outer, outer to inner - to try to get some more miles from them. The theory is that one of them wears more due to different angularity. I've never been too sure about this, as it seems that the axle will make about the same angle with each CV at every position, since the wheel moves pretty much perpendicularly with respect to the car. But not quite - the wheel moves in a shallow arc, and maybe that means the outers have enough more angularity change to matter. Anyway, when I have replaced just one CV on a side I put it on the wheel side just in case, with the "good" old one by the tranny.

The cage that keeps the balls positioned poses a problem. At one time with new cages the balls snapped nicely into the cage. And we were told that if a used cage would not to that, things were toast. Plus a snappy cage makes it easier to reassemble the CV as the balls are less apt to keep trying to pop out one side while you are working on another. I've used race grooving or ball pitting as my criteria, and kind of ignored the cage fit part. But the last set of brand new CVs I bought had cages that the balls just slipped in and out of. No snap at all. Plus the grooves were striated from the machining, not nice and smooth (but not yet shiny) as I was accustomed to find. No REM finishing on these items. Maybe the manufacturer concluded that these things were not important.

Or is the world just going to hell in a handbasket these days?

The saving grace with trying to reuse CVs as a DIYer is that if you guess wrong and they start acting up in a while, you just go back in and replace them with new ones. They won't suddenly fail and leave you stranded in East Nowhere in a blizzard. They will start making noises, which will get worse, but that is apt to be a matter of days at a minimum (if not weeks or months). I ran a VW bus for months with CV noise getting worse and worse before I succumbed to doing the obvious work. Then again I have never, for some reason, had the inner cage break - that might lead to more serious problems.

I have wondered about axle twist. We are all strictly enjoined to reinstall our torsion bars on the same side, lest they break due to stress reversal. So I put tape around my SC axles when first I removed them, and marked things so I could put them back the same way they came off (tape is still there 15+ years later). But it seems that our axles, perhaps because they get stressed a lot more in both directions than the T bars do, don't care. Or maybe they just aren't stressed any where nearly as much.

Some years back Porsche had problems with axles breaking on race cars (993 cups, maybe?) and recommended new axles every year, with a rotation change (swap ends) in mid-season. But this can't affect stock cars. I run used axles on my 2.7L track car (220 RWHP), and I had no clue as to which way was forward in their former life. No problems with them (unlike the new hollow race axles I ran, three of which broke).

One thing you might do is clean all that rust off the axles, and maybe repaint them with a nice black epoxy paint. Rust = stress risers = metal fractures. But you don't hear of axles breaking right and left in normal service, so maybe they have enough extra strength that this isn't an issue, at least as long as it isn't in the splines. But they will look really nice for a while in any case if painted, and you car will love you for it.

Walt Fricke

[Zef]

Walt, thanks a lot for the info. I will disassemble the joints this week and will decide which way to go. If they are full worn, I will may be go with two new complete axle assy. I read that when you have to change all the joints-boots-bolts it is almost more economical to buy full assembled axle. I will keep you informed on my inspection results.

[Gunter]

Walt made some good observations:
When I serviced my CV joints, I made sure that the axles went back having the same rotation.
On SC's, the half-shafts are seperate from the stub-axle; on Carrera's the stub-axle is part of the whole unit.
On my SC, I was able to change the CV's in such a way that they had a fresh running surface by switching them straight over per axle keeping the same rotation on the shaft.
Example: On the left axle, imagine that you slide the outer CV straight across to the transmission side and visa versa. No flipping!
That way you keep the same rotation and get a new running surface.
You have to look at them and do some heavy thinking; it'll only work if the CV's are still in reasonable shape.
I use Zip-straps on the smaller ends of the boots because at high speed, the grease will fly out.

zef: In your case, don't bother reconditioning; get new axles.
With that much dirt, and no lube, there will be too much galling in the grooves. Clean one up and use it as paper weight.
I recommend that you get new Allen bolts and new Schnorr washers. Canadian Tire sells 8mm x 50 Allen bolts with 12.9 tensil-strength.
Use Moly grease and pack the CV's good.
I don't use any gaskets but some people do; its up to you.
Just make sure you snug up all bolts first crosswise, then do the final torque again crosswise meaning by the clock:
12 and 6, 3 and 9 etc.

Oh, what fun.

[Zef]

Gunter...are the Canadian Tire Allen bolts will meet the tensile strenght required by CV joints...?

[Al S]

Re: extending life of CV joints by changing direction; I've done it many times over the decades, on Saab's and Porsche's and never had a problem.

[Gunter]

Originally posted by zefsuper911
Gunter...are the Canadian Tire Allen bolts will meet the tensile strenght required by CV joints...?

Yes, you should see the 12.9 cast on them.
If you don't use the half-moon plates, you may have to shorten the length by about 2 threads. Try a new one and check on how much they stick out on the flanges. But use Schnorr washers, not the regular split lock washers!
I do not use gaskets for the simple reason that they interfere with the torque and are a PITA to install unless you have new grease-free flanges. As long as the mating surface is smooth, there should be no leak.

[Walt Fricke]

I've taken to leaving off the washers as well. Haven't had a problem of any significance. Stretching the bolt (torque) is what holds bolts in place. But they don't hurt, so use 'em if you got 'em.

To check bolt length if you have altered anything, install a couple and rotate to see if they hit any of the transmission ribbing (or something in the hub at that end). If so, you need shorter ones (or to shorten what you have). Not a big problem.

I, too, leave the gaskets out, for the reasons given. And also because it seems that when you use gaskets you have to be careful to go back in after 100 miles or so and retighten. I think the gaskets may compress a little bit, so your initial torque reading may include some not entirely compressed gasket. When if finally thins out more you lose torque, and the bolts can back out. Washers won't help with this.

I used to use silicone as a substitute for the gaskets, but that wasn't helping and I tended to get a bit of leakage (I use thin stamped metal flanges for the rubber boots, and I think they distort a little bit). I've taken to using that blue Hylomar stuff on the mating surfaces, and it seems to do the trick.

Walt