Corvette Axleshaft U-Joint Replacement - Tightening Up Your Rearend

3 Although this is not the preferred way and looks crude with careful hammer blows, the u-joint can be disassembled effectively. The wedge of the heavy hammer is placed on the weld where the tube and u-joint trunnion meet. Sometimes this is the only way to get stubborn u-joints out because of the shock load the hammer delivers.

4 Then there's always the one joint that just won't come loose. We're applying heat to the trunnion while the vise applies pressure to the joint itself. A FEW WORDS OF CAUTION: if the u-joint has a grease fitting, remove it to allow pressure relief as heat builds if it has no fitting. Beware that as pressure builds a small explosion can occur. The ensuing pop can blow the caps off and cause injury if they're not contained.

5 Now that the u-joint cups are pushed out on each side of the trunnion, we grab the cup in the vise and tap upward to release the cup from the trunnion. The cups are usually easy to get out at this point, and the dead blow hammer applies enough pressure for final removal without axleshaft-tube damage.

6 This is the preferred way to remove the u-joints with our u-joint/ball joint press. The cost of the press can be prohibitive for one time or occasional use at $300. The press will remove the most stubborn u-joints where a bench vise will break if the same load is applied.

7 One problem we have found when dealing with tight or corroded u-joints is the axle flange trunnion gets bent. As you push on one corroded cup, it bends the trunnion together during removal, making it difficult to get the u-joint cup retaining clips in place. This trunnion is bent .025 on both sides, so we will need to replace it or fix it.

8 As '63-'82 original Corvette pieces become harder and harder to locate, we find ourselves trying to reuse the original pieces if possible. We found we could use our press to apply reverse pressure on the trunnion, thus straightening the trunnion out. This is one of those easy-does-it fixes. You have to apply enough pressure to go beyond perfectly straight so when the pressure is released, the trunnion is flat. The good part is you can sneak up on it, applying a little more pressure each time until the desired effect is achieved.

9 This is not the preferred way to install the u-joint cups, but very effective. The cross is placed in the trunnion, and the caps are carefully tapped into place. We're holding the cross up into the cup so the needle bearings won't come out and be damaged. The cross must be held up into position while the shaft is turned over to install the other cup.

10 Now comes the tricky part-you need to keep focused on the position of the cross until the other cup is in place. We place the cup in the shaft, then pull the cross up into the cup to be installed. The cross is then centered to keep the needle bearings in place until the cup is tapped into position.

11 The large drift is used to tap the cup beyond the top of the trunnion to avoid snap-ring groove damage. never tap the cups with the hammer or you'll pay the price later as the snap ring won't fit in the groove or, worse yet, the outer edge of the groove can be broken off. We make a habit of moving the cross back and forth into each cup before using the drift to fully seat the cups to make sure the cross sits against the cups' seal surface.