Four bolts at the rear to remove the two straps. Use a pry bar to pop the u-joint out of the yoke. Be careful to prevent the cups from sliding off the cross. The needle bearings could fall down. When you press the cups in, they won't be able to fully seat, and the rear of the cup will blow out.
If you're changing the front joint, mark the two pieces of the drive shaft so they go back together the same way. Although unlikely, changing the orientation between the two parts could lead to an out-of-balance condition and a vibration.
There will be c-clips either inside or outside of the cups that must be removed. The outside style can be squeezed with a needle nose pliers to compress them. The inner style must be tapped with a flat chisel and hammer to slide them off. They could be buried under dirt or mud.
An experienced mechanic will often use a ball joint press, which looks like a real heavy duty c-clamp, to press the joint out. The easiest way for a do-it-yourselfer to do it is to use two sockets and a vise. One socket must be just small enough to go through the loops of the drive shaft. A socket that's too small will press on the center of the cup and could break it. The other one must be big enough for the cup to go inside. Rather than trying to press the cups out with the vise, just put significant pressure on it, then smack the vise jaw with a big hammer. The shock will help walk it out. Keep up the pressure and keep banging away with the hammer. Once the first cup is out and removed from the cross, you'll have to line up the other cup and push it back from where it started, and then keep going to push it out too.
When you press the new cups in, try to always hold them so the needle bearings are standing straight up. If you hold them sideways, there's always the chance one of the bearings will fall down out of position. Insert the new cross and stick it through the loop as far as possible so you can slide the new cup onto it. That will hold the bearings in place while you press the cup in. Push the cup in too far so the cross sticks out the other side. That way the second cup can also be placed onto the cross while it's pressed in. Some people try to press the cup onto the loop and the cross at the same time. That usually works, but it is also the only way a bearing can fall down during installation.
When you press the second cup in, install the c-clip on the first cup before it gets back to its proper position. That just makes it easier to put one of the clips in. If the second cup doesn't go in far enough to put the second clip in place, don't force it. Most likely one of the needle bearings fell over. Excessive pressure will break out the back of the cup. You'll have to press the joint back out to put the bearing back in place.
The new joints will come with a grease fitting. Don't put it in until the joint is fully installed. The joint is usually offset too for clearance for the grease gun after it is installed. The grease in the joint when you get it is just there to hold the bearings in place. Grease the joint before installing the drive shaft and be sure it swivels freely. If it's tight, a few gentle sideways blows on the drive shaft should move the cups just a little to free them up.
Take a look inside the old cups. Look for ripples or imprints of the needle bearings in the roller surfaces. Those surfaces are supposed to be perfectly smooth, but if you find imprints, you should have the suspension ride height checked. The manufacturer specifically designs the drive shaft to change angles so the u-joint needle bearings roll back and forth. This prevents the bearings from hammering impressions into the cups. The transmission shaft and the axle pinion shaft are parallel to each other, but not to the drive shaft. When the ride height is changed, such as from weak springs or purposely modifying the suspension, the angles between the drive shaft and the transmission shaft and pinion shaft are reduced. That's where the u-joint problems come from. The bearing imprints will cause a howling noise when the truck goes up and down over bumps.
As a final note, if the new joint won't go in the last 1/16" when pressing the second cup in, look at the orientation of the retaining clip if it's installed already. If it isn't centered, one end of the clip will bump into the casting. Excessive pressure will break the cup. Just turn the clip with a flat blade screwdriver to center it.
Thursday, April 16th, 2009 AT 12:06 AM