I’ll be trying my hand at replacing my first u-joint today. I’ve replaced almost damn near everything on my 99 Cherokee myself, but never a u-joint. I’ve watched lots of videos and read the write ups for how to, but before I dive in I’m just wondering if any of you guys have any little tips and tricks about the process you’d like the share?
Thanks! Wish me luck. I’m a little nervous about this one to be honest.

Patience. If you get frustrated, stop, do something else. Come back to them when you are in a better frame of mind. I hated doing mine, but hopefully your experience will go better.

New spicer joints - throw them in the freezer until you're ready to install them. The cold contracts the metal and makes it just a smidge easier (and you'll want that smidge)

A ball joint press set into a bench vise to get the old ones out. That's going to be the nastiest part of it. Pop out the retainer clips (they're on the inside for the axle shafts - outside for drive shafts) then soak those f'r's in penetrating oil.

If they are old and/or original, they're going to be a pain and a half to get out - Set up your ball joint press (you'll see folks using a c-clamp or just the bench vise, but if you guys get the road salt up in Canada that we get here in the northeastern U.S., you'll want that ball joint press.)

There will be a scary "pop" when the joint breaks free. If you've done ball joints, it's similar. Don't panic, this is normal.

Make sure you have the joint set up so it's not going to get hung up and use a breaker (maybe a cheater even) bar to press out the old joint.

You might need heat.

Once you have the old joints out, clean up the holes and make sure you didn't ding anything up. If you did, file it down - you don't want the little seals on the new joints getting torn. A little grease (I use mobil 1 synthetic wheel grease) inside the holes will help.

Pull your joint out of the freezer pull the caps off and take care to make sure the needle bearings inside are in place. Use your pinky to push them against the inside wall of the cap if necessary.

Use just the bench vise and start the caps a little on each side, enough to keep them in place but not so much that you can't get the cross of the new joint in between. push the joint as far into the cap and continue pressing one side at a time (basically, use the cross to retain the needle bearings.)

Go slow, it's VERY EASY to get the needle bearings screwed up. Make sure the new caps press smoothly into the axle.. you shouldn't require a lot of effort, don't force it, it'll be tight, but smooth. There's a bit of "feel" involved that will make it easier after a few times.

Now repeat for the other 2 caps.

Once the caps are pressed in far enough, make sure the joint rotates smoothly in all directions. It may be a little "tight", but it MUST be smooth. If you feel any weirdness in the joint, carefully press out the new caps and make sure the needle bearings are all intact... It's not that hard if you're careful to not screw up the needle bearings... if you find yourself overly forcing, step back and make sure everything is correct. Take your time.

Once the caps are in and the joint feels smooth, snap in the new clips and you're good to go. Don't worry, you'll be fine. Just go slow and steady and take care and you'll be successful. I just did a u-joint recently and it's real nice when they're operating per spec.

I have now bent TWO axle shaft ears while doing u-joints. First one was hammer and socket technique on a concrete garage floor, second was using a press. Both times caused by the u-joint trying to go in the hole ****-eyed. Keep 'er straight.

That’s really great info PatHenry, thank you for that!

Good point. Nice and straight. A good bench vise is very helpful in guaranteeing the even application of pressure. If the cap is aligned properly, it will slide in nicely.

This is one of those things that you MUST remember that if you're forcing it, you're probably doing something wrong. (Aside from popping them out.. .that requires a good deal of force...)

No problem. I just did a joint within the last couple weeks and at this point it was like a 10 minute operation... I used to be very afraid of doing u-joints...

One last thing... when removing, once the cap is out a good 6mm or so, you can use just the vise... clamp to the old cap and wiggle the shaft back and forth to yank out the old cap. The leverage of the shaft length makes this a lot easier than using pliers or vise-grips... you just need to be able to get a good "bite" on the old cap to get the vise jaws on.

Me2, both times while taking them out with a press.

They must be straightened out if that happens or the clips will not go on right (assuming you can even get the caps to fit). What I have done is to take 2 wood splitting wedges and put them in opposition between the ears. A couple of whacks and the ears straighten right out.

There was a guy that fabricated a tool or repurposed a tool or something like that to prevent this exact issue. Perhaps it'd be worthwhile to track that thread down...

This is also something that a good bench vise can help with... some have the "stretch open" part, but if you can fit the ears over the vise you can crank it open that way as well.

I tend to think that if you're SURE you have the press aligned such that it's not hung up with a misaligned "receiving" void, and you're using a long breaker bar, then it's time for some heat rather than bending the yoke ears. A good dose of MAP torching is real easy when its on a bench and not on the vehicle.

well this was much, much, much longer than a 10 minute operation.... I rented a ball joint press but it was broken which sucks. I was still able to use it and got the left front axle u-joint out. Like when I grabbed onto it when the Jeep had its wheels on on the ground I could hear it clicking and could move it around. So, to me that means it was ****ed. I took my Jeep over to a shop last week but they wanted a ridiculous amount to change the u-joints which is why I thought **** it I’ll just do it myself. I was able to get the axle shaft out no problems at all, but that ****ing u-joint just didn’t want to press out. After a few hours I was able to get it out and got the new joint in. One side I guess moves nice and easy, the other side was TIGHT as you said, but it moved smooth enough. Bolted everything back together, reversed backwards out of the garage and the popping/cracking/ grinding binding sound is still there... when I brought it into the shop they said both sides needed to be replaced as the right side was seized. I believe they must be correct given the noise I’m still hearing. Grrrr. At least I replaced my first u-joint today. Time for beer.... but thanks again to everyone who gave tips. It helped

I did mine last week, first time on the jeep but I've done UJs on a Range Rover driveshaft once before.
I have one of the giant G-Clamp type balljoint tools and that worked well for me although I'd have been happier if I had a bench and vise to work with.
If you have ABS you have to be careful as it's really easy to break the ABS rings as you take the balljoints out. After I broke the first one, I tried to work out how to not break the second one - but I still broke it anyway
The good news is they're not expensive and quite easy to fit but it's still a waste of time and money.

I'd recommend getting a file and making sure that there are no burrs on the inside surfaces as it's super easy to snagthe seal on the new UJ as you press it in which will reduce the life of the joint. You just need to make sure the outer rim is clear because they can get sharp when people push out the old joints with whatever is to hand and it slips.

I used plenty of PlusGas and everything slipped back together with hardly any effort, no freezing or heat required - but that might just be me getting lucky!

Oh yes, my 10 minute was on a joint that had been replaced within the last 1.5 years... getting the originals out is lengthy.

You should always replace both sides when you do axle joints. It sounds like you had one side where the seal blew and the needle bearings fell out (this is what happened to my 1.5 year old joint after the strap bolts worked loose) and the other side seize up. The popping/binding is definitely the seized joint behavior you would expect.

If you drove the Jeep out of the garage, then the joint that you did was good. I (being I remembered the horrors of u-joint removal) had a shop do my u-joints a couple years back. They handed it back to me and the rear joint felt weird. I attributed it to the normal "tightness" but it was NOT smooth. I stupidly assumed a pro mechanic would not hand me back a drive shaft with an improperly installed joint... I was wrong. I put that thing in and not 25 yards down the road the thing blew out... interesting how easily dropping a driveshaft will pop those caps out.. lol.

Good luck, if you can pull the shaft out and soak it in penetrating oil overnight or longer, it can help quite a bit. A MAP torch to heat up the yoke before cranking on the press will also make a world of difference.

Ack that sucks about taking yours to a mechanic and getting it back worse than if you had done it yourself.. but yeah my plan is to do the other u-joint today. Luckily they aren’t originals in mine. I took it to a shop to have them replaced something like 5-7 years ago. It was shocking at how well the hub assembly came apart. I was sure that was going to give me grief. I think the biggest hitch was I rented a broken press. Like the long bolt had its end sheered off. So instead of having the nice clean punch of a head, I had to jimmy up a socket to the end to push the cap out......... kept dropping the socket and having to push in, back it off, repeat. At least the store I rented it from was cool about it and said they believed me that I wasn’t the one who broke it. I’m really hoping the other-side is just ****ed and that’s all that the noise is and I’ll have her back on the road for this weekend. I’ll be going to a different store to rent the press haha