Question re CV Joint Balls

[Jim Garry]

This might be a bit remedial but I've never actually had a CV joint apart before. I just disassembled one of the Lobros in my sportsracer and the balls look like they might have some very mild pitting. However they feel smooth when you rub them with a finger tip.

Don't know how long these CV's have been in use but they are all dated 1998.

If you have a moment and some expertise, please take a look at the photo and offer an opinion.

Thanks,
Jim

[Steve Demeter]

How do the races look. If they are pitted as well I definitely would replace it. Having had one fail, it is no picnic to thrash to replace it at the track.

Lucky for me it happened in a straight line not a corner.

[Jon Jeffords]

Make sure there are no hairline cracks propagating out of the radiused corners of the cage "windows" that the balls are retained in. 10x loupe magnification will assist with this.

[Jim Garry]

Thank you guys.

[Fred Michael]

It's junk. Replace it now and save some grief when it fails at the most inopportune time.

[TeamFRD]

Jim - I just replaced mine, also dated 98. I've left them greasy but can clean them and take some pics to compare if you want.

BTW GKN (British) bought Lobro (German) sometime since 98.

PS Race-parts.com treated me fair.

~David

[Jim Garry]

David are you saying they looked the same as mine?

[TeamFRD]

After I inspected my CVs dated 88, that were far worse than your pic, I choose to replace those and the other side that were dated 98. I only briefly inspecting the 98s. They sit on the bench in their grease tomb. [My worst case scenario thought was that if those 98s were put on new, there were several years of road racing before the car came to Florida for Solo only duties.]

[Jim Garry]

Make sure there are no hairline cracks propagating out of the radiused corners of the cage "windows" that the balls are retained in. 10x loupe magnification will assist with this.

Jon, i see no cracks but there are indentations from the balls. Please see photo. Is this a problem?

[chrisw52]

looking at those races, the ball bearings, and reading the other comments, I would replace them to be on the safe side.

[Charles Warner]

If you want to reuse the current units, magnaflux the cages and the housings and buy new balls. You might consider buying balls that are .0005" smaller which makes for easier movement. Then, when you find cracks in any of of the cages or housings you'll have to . . . . .

buy the lightened units from Taylor Race (or others). Anything else is really false economy. The price for the magnafluxing makes buying new ones a no-brainer.

[S Lathrop]

I think you should replace the joints. The roughness on the contact area of the cages really is a bad sign.

It is possible to buy undersized balls. I take new CV joints and run undersized balls for the first season and then replace them with the original balls. I run undersized by .001 to .002.

I do not like how stiff new CV joints can bee and running them in is likely where the pitting starts. If the joint is stiff without a load, you can guess how much stiffer it will be once the power is applied.

Stiff or bad functioning joints do nothing good for mechanical grip.

[Jim Garry]

Going undersize for early use of new CVs sounds like a good thing to do. Where do you source your CV balls from Steve?

[S Lathrop]

Going undersize for early use of new CVs sounds like a good thing to do. Where do you source your CV balls from Steve?

Applied Industrial Technologies, applied.com

[Rick Kirchner]

I can't remember where I got the tip, perhaps from one of Carroll Smith's books - but he suggested taking a cartridge roll and smoothing all the edges in the cage.

I also baked on some dry film lube before re-assembly.

[R. Pare]

Jim:

If you have the usual lightening cuts done on the OD of the body, you will definitely need to go to the undersized balls. once you get your new CVs, let me know what the ball diameter is - i have box of balls of different sizes somewhere upstairs that might work.

And yes - break all the sharp corners of the cages.

[SCOTTY81]

I would replace them Jim , Once they start to pit it is all down hill .
I have the lightweight Gold GKN on the shelf as well as the standard GKN. I can take them apart a polish ball tracks to free them up .

[cgscgs]

I bought a bag of 25 balls, 21/32" (a couple thou undersized) from Emerson Bearing in Boston. 25 cents each (min 25). Also a great source for bearings.

[alangbaker]

On this topic, I got a smoking good deal on some lightened CVs from a guy who was clearing out his garage prior to a move. I think I paid him $10 a piece for 4 new joints.

But they seem very tight, so I'm thinking that slightly undersized balls might be a good idea for me, to. If I go that route, is 0.0005" undersized about right (5/10,000), and is there anything else I can usefully do to prep them before assembly.

What about grease? Is it important to get anything more than a good quality CV joint grease? I've got 4 packets of Moog 3301. Is it suitable?

On a related note, I've removed and disassemble my existing standard CV joints, and someone suggested to me that because I didn't keep the balls assigned to specific races that they're all junk now. Is that true?

[R. Pare]

Half a thou' will usually do it, but not always.

On the used CV's, as long as the balls show no pitting, it doesn't matter which race they go back in to - it is not a selective fit when they are first made, and the balls will rotate in enough different directions during use that there is no "mateing' of a ball to a particular race, unlike something lik roller bearings.

[DanW]

What about grease? Is it important to get anything more than a good quality CV joint grease? I've got 4 packets of Moog 3301. Is it suitable?

The Moog grease is the right stuff to use. It has the right additive package for CV joints. It also resists oil and thickener separation from the centrifugal forces. Most general purpose EP greases separate quickly in a CV joint.

[alangbaker]

Thanks, Richard. Good to know.

And thanks, Dan.

[924RACR]

Redline CV grease is also very good, of course, if you're buying, and Valvoline Synthetic is also rated for and good in CV's (unlike Mobil1 synth, which is very much not)...

[DaveW]

Redline CV grease is also very good, of course, if you're buying, and Valvoline Synthetic is also rated for and good in CV's (unlike Mobil1 synth, which is very much not)...

I've been using the Valvoline synthetic grease for years with no issues.

[924RACR]

Same here, particularly in our 924's, which have the same CVs of course... I particularly like only mostly needing to stock the one grease, perfect for wheel bearings and CVs alike...

[Onebadbug]

Redline CV grease is also very good, of course, if you're buying, and Valvoline Synthetic is also rated for and good in CV's (unlike Mobil1 synth, which is very much not)...

I was about to recommend Mobil 1 grease to the original poster. That's all I ever use, and have never had to repack CV joints again. What is your reason for not liking it?

[R. Pare]

Note on greases: do not mix CV grease and wheel bearing grease. Many times - but not always - there are components in one grease that are no compatible with components in the other, and the grease will fail - along with your wheel bearing or CV. A mechanic on the TWR GTP team made that mistake many years ago, and the failed CV almost destroyed the car.

[xmazdatracy]

I have one lightened CV that is considerably tighter through its plunge than my other three regular lobros. After reading this thread I would like to try some smaller balls. I have .686 balls in all 4 CVs, and would like to ask anyone whom has 6 of the 21/32 size laying around. Or if the grade 25 balls from applied.com are a good purchase?

Thanks!

[Steve Demeter]

Probably should not do this.

I took an electric die grinder running very slowly. Had about a 600 grit sandpaper roll on it and lightly touched each groove in the outer housing. Repeat a couple of times and it is now nice and loose.

YMMV

[SCOTTY81]

You are correct Steve Demeter.
I hone and polish dozens of CV joints a year . A 1/2 x 1 1/2 x 1/8 Cartridge roll on an grinder. No need to be changing out balls to different sizes . We charge $25 per joint , And I have to zip tie them when I am done or they fall apart .
Hone , polish , assemble , and go racing .

[Jon Jeffords]

Hone , polish , assemble , and go racing .

Scotty, do you consider your cartridge rolling to be the honing process or the polishing process? And what then is the other process? Do you do this to both the inner and outer pieces?

[DaveW]

You are correct Steve Demeter.
I hone and polish dozens of CV joints a year . A 1/2 x 1 1/2 x 1/8 Cartridge roll on an grinder. No need to be changing out balls to different sizes . We charge $25 per joint , And I have to zip tie them when I am done or they fall apart .
Hone , polish , assemble , and go racing .

On that note, FYI, only a few 0.0001's (for emphasis, 1/10 of 0.001") needs to be removed to go from way too tight to just right. That's why hand honing is effective. Removing a full 0.001" would likely be overkill.

[SCOTTY81]

Jon.

Sorry for the miss communication. It is more of a hone .
Yes , I do both the hub as well as the housing .
As Dave W points out. It does not take much when you are talking 12 surface areas.
Hone it , clean it and then re-assemble. You will be to feel which track you need to clean up once you assemble the joint and move the hub around

[stonebridge20]

We like to REM-ISF treat CV'S for the ultimate in low friction. Of course, that's after we Cryo treat them first!

[BorkRacing]

I bought a bag of 25 balls, 21/32" (a couple thou undersized) from Emerson Bearing in Boston. 25 cents each (min 25). Also a great source for bearings.

I measured the balls at 0.685
21/32 is 0.656
That is more like a couple of hundreths...are there 2 sizes of balls?

[cgscgs]

Mr Bork. The 21/32" balls I referred to are for the CV from an Austin Princess, which is what my Tiga has (outers). YMMV.
Chuck

[BorkRacing]

Mr Bork. The 21/32" balls I referred to are for the CV from an Austin Princess, which is what my Tiga has (outers). YMMV.
Chuck

Who knew a princess had balls...thanks for the morning smile!

[Jon Jeffords]

Who knew a princess had balls...

You've never been to Thailand, apparently.

[EricP]

You've never been to Thailand, apparently.

I can’t believe it took this long for a balls joke!

[BorkRacing]

On a more serious note.

Recently I purchased 4 new lobro CV joints. Two moved perfect right from the package. One was a little stiff but with a touch of polishing it is good. The fourth came so tight I could not move it. Once apart I noticed the balls were not smooth and brightly shined like all of the others. I polished it as is the norm and it still did not move freely. I took balls out of one of the other joints and placed them in the tight joint, problem solved. Has anyone run into this where the ball bearings are a poor grade?

Robby