Broken Baler U Joint

Broken Baler U Joint

When taking up hay, we broke the U joints on the baler PTO drive line (unfortunately as soon as we turned it on the first day).

An emergency trip to Tractor Supply and some field repairs got us running again. Unfortunately we broke another one at the end of the first day that required another trip to Tractor Supply the next morning. That one got us through the second day, but this one also broke when we were rebaling lose bales a day or so later. I decided to go to the parts manual, and it turns out the part that was already on the baler was too small. This would require a new upper shaft with a bigger yoke, new U joint, and new quick connect.

The first step was to trim the PTO shaft to the correct length and grind the sharp edges.

The next step was to insert the U joint into the yoke. Unfortunately I learned the hard way (ruining a U joint) that even at $120 you can't expect a part to be manufactured with any level of quality or precision. The yoke had burrs on it that prevented the U joint cups from seating correctly in it. To remedy this, we used a Dremel tool to remove the burrs.

The next step was to install the U joint on the yoke.

U Joint with two caps removed

To install the U joint in the yoke, you remove two of the caps, put the cross section in the yoke with the posts lined up with the holes, then snap the caps into the holes.

Now that the caps are in place, it's easiest if you just use a hammer to get the cap started until it's flush with the yoke.

Now that the caps are flush, you know everything is lined up correctly. Place one of the caps on a hard surface like an anvil or vise, then use a hammer and punch to drive the other cap further into the yoke until it's further in than the groove for the snap ring.

Snap rings are used to prevent the caps from sliding back out.

The next step is to install the snap ring on the side that has been driven into the yoke.

The cup has been driven further than it needs to rest, but that's about to be fixed. Turn the yoke over, and use the hammer and punch to drive the other side in. You don't want to go too far on this side or it will blow out the snap ring on the other side. Once this side has been installed, both cups will have settled to the correct spot.

The next step is to install the U joint on the quick connect. Once again, you take the two caps off and line up the posts with the wholes on the quick connect.

Again you push the caps in the holes with your fingers and use a hammer to get the cups flush on each side, ensuring everything is properly lined up.

Using the hammer and punch, press the first side in and install the snap ring. Turn the quick connect over and install the other cap and snap ring.

During this process you have probably noticed a hole that has been squeezing grease out.

The final step is to install a grease nipple in this hole that allows you to grease the bearings in the U joint. You can finger tighten the grease nipple, then finish tightening with a wrench.

Now you've got a new PTO shaft ready to go.