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
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.
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
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
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.
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
drive pin needs to be adjusted slightly so that it’s
even on both sides.
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)
• Mugen Seiki Racing Ltd., 20914 Bake Pkwy., Suite 106, Lake
Forest, CA 92630 • (949) 707-5607; fax (949) 707-5614