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Proper CV Prep

Proper CV Prep

Here’s how your CV should look on the axle (less grease).
With the axle removed, pack the grease with a grease needle attachment for your grease-gun.

To clean up an existing CV it’s nice to have a solvent tank. But if you don’t have one of those, use a roll of paper towel and be patient, go slow, and read all of these tips below BEFORE you start the job.

Make sure the CV will slip onto your axle splines easily. DO NOT use a hammer to tap it on. If the CV doesn’t slip over the spline easy, look at the axle end with a magnifying glass to check for spline damage. Sometimes the splines can be mushroomed on the end. If they are damaged, sometimes a fine file with a 90 degree edge can clean up any damage to the end.


Hint: This picture shows an axle with a flat end, which is old school. The new style axles have a dome on the end to prevent the mushrooming of the splines. If you’re buying new axles, insist on the dome type, they work better. This axle shows signs of mushrooming, which requires tedious filing of each of the splines with a triangle file. It’s not fun, but it needs to be done. As the axle ages the filing job becomes easier each time you service the CVs because there’s less metal to file. It eventually turns into a quasi domed axle….kinda sorta.

A key trick to assembling your CV is to insure the orientation of the inner star gear and the outer case is correctly aligned. It’s not difficult if you know the secret.
When you start installing the ball bearings you simply have to line up the WIDE walls of the inner “star gear” with the NARROW walls of the “outer case”, and vice versa, as shown with read lines in this picture. If you do this right the CV will swivel around like it needs to for long travel suspensions. If you do it wrong the CV will have almost NO MOVEMENT to pivot freely. You’ll immediately know something is wrong because you’ll struggle bolting up the CV’s to the trans flange and hub assemblies. There’s a 50% chance you can do this wrong if you’re not aware of this assembly trick.

CV Clocking
In some applications where 930 CV’s are stretched to the limits of their angle range you may need to “clock” the two CV’s with each other, perfectly on the splines. Cars that do not stretch the limits of a 930 CV past the recommended 26 degree range may not need CV clocking to work flawless, but it’s a good idea to clock them anyway, regardless of the max angle setup. If you’ve never clocked your CV’s and you’ve never had a problem, that’s because your car is designed within the 930 CV range limits, which is a good thing.

Clocking CV’s takes little effort, just the knowledge of how to clock them and the ability to remember to clock them when you’re reassembling your axles during your annual CV service. So clocking CVs is a good thing to do since it’s free, easy, and effective.

Annual service? Yes, to maximize the life of your CV’s you should remove and inspect them annually. Checking the ball bearings for wear, along with inner and outer bearing races of the inner star gear and outer case on an annual basis is advised. If you only go to the dunes a few times each year, inspect them every 15 trips to the dunes. This will minimize the risk of breakdown during your valuable duning time. It will also minimize the risk of ruining an axle caused from a broken star gear. Annual maintenance will reveal abnormal wear before it’s serious enough to break and mess up the axle splines.

To clock your CV’s you must understand this simple rule of thumb, Wide aligns with Narrow. In this picture look at the outer case bolt holes. Each hole has a corresponding race wall width, or “gear width” as some folks call it. 3 of the holes have a WIDE width, the other 3 have a NARROW width. To align them properly look at the inside of each CV installed on the axle, viewed from the center of the axle. The objective is to align a WIDE race wall on one CV with a NARROW race wall on the other CV. “Wide aligns with Narrow”, as shown in these pictures.

In addition to “eye-balling” the alignment, to insure alignment of the CV’s on the splines, you could also buy a 3/8″ steel rod the length of your axle and insert it into one CV hole of each CVs after you think things are aligned. These holes are exactly 3/8″ ID. When the rod is installed there will be no question about alignment if the rod easily fits through and the CV are square with the axle, assuming the N and W holes are aligned as illustrated. When the rod is installed, both CVs must be square with the axle, perpendicular. If they aren’t, you’re likely not aligned, possibly off by one spline.

These two pictures (above and below) depict the right axle assembly. The left side would look the same.

N aligns with W below as shown with arrows.

Both CV’s are the same so it doesn’t matter which one goes to the transaxle, but it does matter which side you reinstall a used axle. Always install the axles on the same side as it was originally installed to keep the twist pattern of the axle the same.

Axle Orientation

When servicing your CVs it’s very important to install your axles on the same side as they were previously used when reassembling. So before you start yanking out the CV bolts, use a felt marker and mark each axle:

RIGHT and LEFT Comprendo?

If you orient the axles identical to how they were removed this will insure the twist pattern of the axles will be in the same direction as they were originally “broken in”. If you fail to install them on the correct side, and reverse the twist pattern of the axle, this can weaken it, possibly inducing failure. And if you don’t think axles twist, take a look at the chipped powder coat of this axle near the splines in these pictures. Yes, they twist, and they set a “twist pattern” from the first day of use.

Some folks are also anal about keeping the axle orientation on each side the same, which isn’t a bad idea. But if you have the right side axle on the right side, flipping end to end doesn’t reverse the twist. But some folks believe the twist may be different since power is delivered from the transaxle side. Whether or not axle orientation (flipping ends) on the same side makes a difference is a good discussion to have around the campfire at 1am. 🙂

Don’t forget to label the axle side BEFORE disassembly. The felt markings can be removed later with lacquer thinner, or simply mark them in the area UNDER the CV boot so it won’t show when reassembled.

DO NOT mark the axles with an engraving tool !! BAD idea.

 

A technical guide: How to properly prep CV Joints. This will be a comprehensive three part guide on how to prep your CV joints PROPERLY.

Grease Guide

Hardware Guide

Polishing

Clearancing

Cooling  / Lightening

Max Angles

Axle Clip Clearance