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How to install U-joints

We now need to refurbish the driveshafts on our ongoing Jeep restoration project. That includes 
new U-joints

Project CJ3A is now well into the reassembly phase. It’s taken a long time getting to this point.

With our attention now turned to finalizing driveline components, it’s time to take a look at the driveshafts. Before installing them, we decided to replace all the U-joints (otherwise known as universal joints). We took out the old U-joints, cleaned and painted the driveshafts, and freed up the stuck slip joints.

There are a few different techniques to use when tackling U-joint replacement. But we wanted to use only basic hand tools to demonstrate how this job can be done in any farm shop — or as a field repair. Here’s how we put the new ones in.

Out with the old

First, let’s take a look at how we got the old ones out. Ours are held in by snap rings on the outside of the bearing caps. (Some types have C-clips on the inside.) We used needle-nose pliers to slip them out of the groove in the driveshaft yoke.

But that was easier said than done. Almost all of them were rusted in place. We sprayed some WD40 onto the U-joint caps. Then we used a small screwdriver and the pliers to finagle them out.

Once the snap rings were removed, we rested the trunion arms of the U-joint on top of bench vice jaws. With an impact socket wider than the bearing caps, we pounded the socket down on the yoke, forcing each bearing cap up and out.

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After they were removed, we had to ensure there were no burrs on the driveshaft yoke, which could interfere with installation of the new bearing caps. If there were any, they’d need to be filed down. A quick rub inside the holes of the yoke with fine-grit sandpaper shone up the surfaces, readying them for the new bearing caps. It was also necessary to clean all the crud out of the snap-ring groves.

In with the new

To get the new U-joints in, we positioned a new trunion in place inside the driveshaft yoke and put a new bearing cap in one ear of the yoke. With the driveshaft on a workbench, a large-faced hammer was used to tap the new bearing cap flush with the yoke. The driveshaft was flipped over and the process repeated on the other side.

Next, a socket with a diameter smaller than the bearing cap was used to tap the cap into the yoke below the snap-ring grove. After installing one snap ring, the yoke was again turned over and this step repeated. A couple of firm taps on the ears of the driveshaft yoke with a hammer relieves any stress on the U-joint and allows the bearings to spin easily. You’ll be able to feel the difference when wiggling the new joint after doing this.

When installing the bearing caps be careful to keep the needle bearings in place inside the cap. If any fall out of place, they can be put back into position with a small screwdriver — assuming you don’t loose them.

Our U-joints are grease-able, so we had to remember to give them a good shot of it after the driveshafts were installed. And we had to be careful to position the grease zerks in the correct orientation, allowing for easy access.

If you have access to a press in your workshop, that can make installing and removing the bearing caps an even easier (and quieter) job.

About the author

Contributor

Scott Garvey

Scott Garvey is a freelance writer and video producer. He is also the former machinery editor at Grainews.

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