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The only link between your Corvette’s transmission and the rear
end is the driveshaft. All of your car’s power is transferred to the
rear end through the driveshaft. It is an integral part of the
drivetrain which is often overlooked. A driveshaft with loose or worn
u-joints can cause vibrations, loss of power, worn seals and bearings,
not to mention transmission or rear end damage. Worn u-joints are also
dangerous. If a u-joint breaks during speed, it can cause the
driveshaft to break. Do you know what kind of damage a broken
driveshaft can do to the underside of a Corvette at only 3000 RPMs? Can
you say, large hole in the floor! (If you are lucky and it doesn’t pole
vault your car into space.) Even if you are lucky and none of this
happens, damage from a broken or seized u-joint is never minimal. The
u-joints should be tight, never loose or sloppy. They should be checked
every 10,000 miles or more in extreme conditions. U-joints should be
changed in a press, but since most home workshops do not have one, we
are going to show you how it can easily be done using a bench vise.
While we are at it, we will also freshen up the driveshaft’s outward
appearance using some simple products and a little manual labor.
Our Project 77 needed a pair of new u-joints so we contacted Zip Products, Inc.,
8067 Fast Lane , Mechanicsville, VA 23111(800) 962-9632. and they were
able to supply everything we need. With our new parts in hand, let’s
get started.
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01: Zip supplied us with the following parts: 2
u-joints with internal and external clips, 4 driveshaft u-joint straps
and 8 driveshaft strap bolts. You will also need some common hand
tools, 4 jack stands, a hydraulic jack and a bench vise. |
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02: After the car is securely on jack stands, start
the disassembly by marking the transmission end of the driveshaft. This
way the driveshaft will be re-installed in the same position that it
was when it was removed. |
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03: Remove the u-joint straps and bolts and remove the driveshaft. |
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04:
I like to use a punch to make a more permanent mark on the transmission
yoke end of the driveshaft. This will be very helpful during
reassembly.
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05: Remove the u-joint cup retaining clips. Use vise
grips, needlenose pliers or small pliers to squeeze the ends of the
clips together, then pull the clip out. |
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06: With the clips removed you can then press out the
u-joint cups. Always support the driveshaft itself while pressing out
the cups. Never let it hang. Use a 1 1/16” socket as a support and
receiver on one end and place a 11/16” socket into the center of the
opposite u-joint cup. (If your vise will not open up far enough to use
the 11/16” socket, start with a 1/2” lug nut when it is pressed in far
enough. Change to the socket.) Slowly close the vise and press the
11/16” socket into the center of the u-joint. This will push the entire
u-joint toward the other side and push out the opposite u-joint cup
into the 1 1/16” socket support. The u-joint will bottom out against
the driveshaft yoke. |
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07: Remove the driveshaft from the vise and use
pliers or vise grips to pull the cup the remaining way out of the
driveshaft yoke. Put the driveshaft yoke back into the vise set up the
same way as before and push the u-joint and remaining cup back into and
then out of the driveshaft yoke. Now remove it from the vise and again
use either vise grips or pliers to remove the remaining u-joint cup.
Now you can totally remove the u-joint. Repeat this process on the
opposite end of the driveshaft. |
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08: With the u-joints removed it would be a good time
to clean the driveshaft. Grease and grime can be easily removed with
mineral spirits and a brush. |
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09: If you would like to refinish the driveshaft,
start with a coarse wire brush to remove any rust or scale deposits.
Then start with 220 grit sandpaper and sand the entire driveshaft. When
this is done move on to 320 grit and repeat the process. Then finish up
with 400 grit sandpaper to smooth out the surface. |
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10:
For a clean natural steel appearance without alot of effort use
Stainless Steel Spray. This will give the driveshaft a new look.
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11: Start the u-joint reassembly by pressing in one
cup about half way into the yoke. Make sure you keep the cup centered
and support the driveshaft. |
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12: Install the u-joint into the installed cup. Make
sure that all of the needle bearings are in place and have not fallen
down into the bottom of the cup. Also check the direction of the grease
fitting. You want to be able to get to it when the driveshaft is
installed. Now place the other cup into the yoke and center the u-joint
into it. It is very important to keep the cup centered. If it becomes
cocked, you can damage the cup or the yoke. By keeping the u-joint
centered in each cup, the needle bearings are less likely to fall out
of place. Use the 11/16” socket to press the u-joint cup back into the
driveshaft yoke. Press the cup in far enough to install the retaining
clip. Remove the driveshaft from the vise and install the one clip.
Remember to support the driveshaft when installing the u-joints. |
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13: Now place the driveshaft back into the vise and
use the 11/16” socket to press the other cup in far enough to install
the other clip. NOTE: If the cup on either end will not go in far
enough to install the cup, the problem will usually be a needle bearing
that has fallen down into the bottom of the cup. The solution is to
remove the entire u-joint, press out the cups and start over. See, I
said it was important to keep the u-joint centered! |
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14: With the u-joint in place, install the grease fitting. |
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15: Before you re-install the driveshaft, you may
want to remove the transmission yoke and check it for wear. I like to
clean up any slight grooves or knicks with emery cloth or 400 grit
sandpaper. |
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16: Remember to look for your identification mark so that you can re-install the driveshaft in its original position. |
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17: Use new u-joint straps and bolts and re-install
the driveshaft. A large flat blade screwdriver will work to hold the
shaft in place while you tighten the bolts. |
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18: After the driveshaft is installed, use your
grease gun to lube both u-joints. Put the car back on the ground and
you are set for thousands of trouble-free miles. |
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DRIVESHAFT U-JOINT REPLACEMENT :
63+ DRIVESHAFT U-JOINT REPLACEMENT
By: Greg Donahue
Photos by: Author
SOURCE:
Zip Products, Inc.
8067 Fast Lane
Mechanicsville, VA 23111
(800) 962-9632
PARTS LIST:
The Author would like to thank
Scott Coral of Greg Donahue Collector Car Restorations, Inc. for his
assistance with this article.
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