Replace CVD Pins

Tighten up the driveline for less $

Words: Stephen Bess

Universal drive shafts and CVD joint shafts eliminate much of the slop associated with old-school dog bone driveshafts, providing smoother power delivery and less drive train chatter. Over time, your vehicle’s driveline will wear—it’s inevitable and unavoidable—and slop will develop. Three areas get sloppy the quickest: the outdrive cups, the CVD joint, and the CVD pins. In this how-to, we’ll show you how to save some cash by replacing those pressed-in, worn out CVD pins after they’ve flat-spotted.

1) Are They Worn?

Before you replace anything, it’s a good idea to determine whether the universal is actually worn or not. Universal driveshaft wear is easy to evaluate, since only two wear areas exist. The barrel joint can wear (and if they’re not rebuildable, you may waste your time replacing the drive pins), and the drive pin can flat-spot.

2) Assuming the barrel joint is still tight, you can replace the drive pin easily to tighten up your driveline just like new. Remember - when replacing the universal drive pins, it’s always a good idea to replace the differential outdrive cups as well to prevent unnecessary wear.

3) The Tools

To do this job right, you’ll need a tool capable of pushing the drive pins out of the CVD bone end. We used a motorcycle chain breaker, part number #08-0058 shown here, made by the motorcycle company “Motion Pro.” Chain breakers use a steel pin to accurately drive the CVD pin out of the drive bone. The only other tool we’ve found that works like a chain breaker is Innovative Designs’ “Bone Saver” micro press. In either case, you’ll need a chain breaker-style tool, “red” permanent thread locker, and a bag of cross-pins specific to your vehicle’s CVD driveshafts. In our Mugen CVD example, we used Mugen’s C0270 3x12.8mm pins for the center CVDs, and C0271 3x13.8mm pins for the front/rear CVDs.

4) The process begins by pushing the worn, flat-spotted CVD drive pin out of the dogbone end. Using the chain breaker, install the thickest drive pin into the tool, and center the dogbone on the tool’s mount surface.

Press ‘Em Out

5) Going very slowly, push the worn pin out of the dogbone and stop to realign the drive pin if the dogbone wanders or begins to slide sideways. Once you’ve pushed the pin halfway through, change to a thinner drive pin to complete the pin removal.

6) Once this step is complete, you should have the pin completely removed, and an empty dogbone end.

Press ’Em In

7) Add a drop of red permanent thread-lock liquid to the open dogbone end before installing the new drive pin.

8) The threadlocker will help keep the pin in place even if the friction fit between the pin and the dogbone isn’t as tight as it should be.
Reinstall the thickest drive pin back into the chain breaker tool, and align the dogbone on the breaker tool so that the new CVD pin is perfectly aligned with the tool drive pin.

9) Slowly (very slowly!) turn the breaker tool bar to push the new drive pin into the CVD, and stop often to check its alignment inside the dogbone end. Adjust the new pin until it is evenly inserted on both sides.

10) This drive pin needs to be adjusted slightly so that it’s even on both sides.

You’re Done!

Replacing worn CVD drive pins isn’t all that difficult when you use the correct tools. Remember, whenever you replace a CVD drive pin, it’s important to replace the differential’s outdrive cup as well to get the most out of your work. A tighter fit between your driveline components means more driveline efficiency, smoother operation, and a faster, more reliable car. o


• Motion Pro, 867 American Street, San Carlos CA 94070 •  (650) 594-9600
• Mugen Seiki Racing Ltd., 20914 Bake Pkwy., Suite 106, Lake Forest, CA 92630 • (949) 707-5607; fax (949) 707-5614