Protect your driveshaft by replacing a worn U joint
Worn universal joints, or U joints, can be a real aggravation. They clunk when you let the clutch out or pull the transmission lever into drive. They also clunk each time you get on or off the throttle. Even more irritating is the vibration that increases with vehicle speed. If not replaced, worn universal joints can come apart, spitting your driveshaft into the street (if you're lucky—if you're unlucky, it can result in a serious accident). Universal joints are relatively inexpensive to replace. Driveshafts, on the other hand, will cost you a pretty penny.
Replacing these joints is a fairly straightforward job, though it takes some prior experience. To begin, you'll need a universal joint pressing tool. You can also take advantage of the loaner tools program at your local Advance Auto Parts store. Then follow these step-by-step instructions on how to change U joints.
This is a challenging and technical project
Mark the shaft for reinstallation. Remove the U bolts, then slide the driveshaft forward into the transmission with a large screwdriver. It should slide forward enough to drop clear of the pinion yoke.
Remove the internal/external C-clips or press out the injected ring of polymer holding the U joints in place. For polymer, be prepared to use extreme pressure to remove the joints. Heat may be required, so have a heat gun or small Prestolite torch handy.
Press the U joint out one side of the shaft. Remove the bearing cap and then press the joint and bearing cap out the other side. Handle the driveshaft carefully while doing this.
Stop to compare the old part and new part. Then, reinstall new joints by removing the bearing caps and needle bearings. Carefully twist the cap back and forth to remove.
Slip the universal joint cross into the driveshaft bearing loops. It takes a little perseverance to get the joint into position.
The new bearing caps are then pressed into the driveshaft with a universal joint press. Don't be tempted to just make do using a bench vise—if you put even the slightest dent in the driveshaft, it can put it out of balance and then you'll have a whole new set of problems. Make certain that the joint cross is aligned with the caps while pressing in place. Be careful not to allow bearings to shift. This is tricky, so be patient and take your time.
After pressing in the new joints, the snap-ring C-clips are pushed in place by hand. The universal joint must be perfectly centered in the driveshaft to install the C-clips.
This can be a fairly dirty job. Spraying everything down with brake cleaner or a similar solvent can make it a little less unpleasant.
Watch Chris Fix's Ultimate Guide to Universal Joints
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