Replacing u-joints

[BumpyJohnson]

My truck has the 2-piece driveshaft and all three u-joints need replacing. I've never done it before. What's the procedure?

[averagef250]

Lay driveshaft on the ground, remove keepers and zerks. Use a ballpeen hammer and a couple steel blocks to support the shafts and knock the old joints out. Install new joints reverse of disassembly. Tap joints with hammer to seat the caps and feel how they turn. It's best to watch someone who's done this thousands of times so you see how it works.

You can use any manner of press to remove joints, but the likelyhood of bending the ears goes way up, especially on the old rusty stuff. The hammer is the right tool for the job. The shock gets the joints moving and makes the job much quicker.

[Madman]

I have always used a vice and a few sockets. On one side, I put a socket about the size of the cap of the ujoint, slightly smaller is ok too, and on the other side, a larger socket. The ideais as you tighten the vice down, it pushed the smaller socket, forcing the ujoint over, and into the openning of the larger socket. The cap is displaced into the larger socket, and you should be able to remove the rest of the ujoint. Hopefully this makes sense, and you can see it in your minds eye.

[Bob]

I agree with the hammer for removal but I use a press to put the new ones in. As a general rule... never a good idea to beat on a bearing. The "potential" problem with the sort of blow that tapping them back in is the chance of hard spotting the bearing races which can lead to an early demise for the bearings.

Side note... probably want to consider changing the carrier bearing while you're at it.

[PhantomoftheBumpside]

Clean. Mark the driveline for orientation at each joint. Remove Driveline.

To remove U-Joints.. Hammer & Drift, or vise and socket for press, or run your bench vise out a bit so you can stick the end of the DL in while resting the two free trunnions (a u-joint is 4 trunnions) on the jaws and hammer like an angry monkey, this also usually involves slapping the DL back and forth for additional satisfaction and to confuse onlookers.

CLEAN everything really good. Change the carrier bearing (have described this elsewhere) since it probably needs it too... Re-coat drive line since you have it out (just make sure to keep orientation marks)...

Carefully press in new. Or carefully use a hammer and drift to tap in new, but those trunnion caps are not indestructible (and the pins can be hard to find when you knock things apart and you drop them.

Reinstall drive line. Jack stands and jacks can be your friend here...

Save up your pennies to buy a good sized Arbor Press for next time...

[averagef250]

I agree with the hammer for removal but I use a press to put the new ones in. As a general rule... never a good idea to beat on a bearing. The "potential" problem with the sort of blow that tapping them back in is the chance of hard spotting the bearing races which can lead to an early demise for the bearings.

Side note... probably want to consider changing the carrier bearing while you're at it.

You're not beating on the bearings, you're beating on the caps. They are harder than your hammer and there's no needles in the ends.

Bottom line is you will bend the yoke ears on a difficult joint long before the joint even thinks about moving in a press, vice, U-joint press, whatever press you have, but a hammer will never bend the ears.

A hammer used correctly will easily remove the stuckest, biggest U-joint in a couple blows. It will install just as well too.

[Madman]

You wont bend the ears in a vice using the sockets as spacers, but I'd have to have a picture to clearly show how they go. It is a very smooth process when done correctly, but whatever works for you.

[BRUTUS_T_HOG]

i have never been able to break old u-joints loose using a vise and sockets, installing new ones is great using that method though.

i recommend getting an experienced vet to show you hands on. otherwise you are likely to do damage

[BumpyJohnson]

I don't have a bench or a vise, nor do I have an expert to help me. Thanks for scaring me, guys!

I have access to basic tools, including a ball peen hammer, but I live in an apartment and have basically no money, so my resources are extremely limited.

[72BahamaBlue]

If at all possible, have a pro replace the u-joints and carrier bearing, and balance. It's also nice to align the zerk fittings in a row, makes it easier to lube; give each a squirt or two each oil change.
If you are installing, check for any dents or other defects, discard if so. A specialist can rebuild if needed.
I agree with Brutus T Hog, find a veteran mechanic to show/help you! You do not want a driveline failure. Ever.

[averagef250]

You wont bend the ears in a vice using the sockets as spacers, but I'd have to have a picture to clearly show how they go. It is a very smooth process when done correctly, but whatever works for you.

For one, a vise isn't a press. For two just how do your magic sockets support both yoke ears while pressing the joint? You're only supporting one of the ears, not both.

I think the hammer method is something that's hard for someone who's never been around this kind of thing to grasp. It's the right tool for the job, but it takes using it correctly otherwise you get nowhere. A big nasty stuck U-joint is a 2 minute changeout max with a hammer and an operator with a clue.

I also wouldn't argue with the suggestion to take it to a good driveline shop. For your typical one piece automotive shaft the shop I use charges about $70 for disassembly, hot tank, new joints and balancing.

[Bob]

??
A vice is a press. It's same exact thing except it's driven by a screw instead of a gear on a rack or a cylinder.

I'd take U-Joints out every day of the week with a hammer but never install them or allow anyone to install any bearing in anything I own with a hammer. Hard spotting a bearing is easy to do. Believe it or not... If you really want to get anal about bearing care and maintenance they say you should rotate a bearing that is just sitting on shelf to prevent vibrations from ambient noise from hard spotting them.

Yes you're hitting the cap... but bearings should never be beat on. That shock doesn't stop at the surface of the cap. It continues on to the pins and then to the shaft. I've been dealing with bearings for years now and some really pricey ones too. A change in one of our machines here at work requires about $30,000 worth of bearings that entails just three big bearings and a half dozen smaller cheap ones. If I ever caught one of our guys beating on them they'd not likely appreciate what I'd have to say to them.

Now far as bending the ears of the yoke installing the caps with a press goes here's my take on that. If you bend the ears on the yoke installing with a press the yoke was junk anyway so you did yourself a favor by scrapping it. If the pressure required to install the caps is so high that it would cause bending... then the fit is incorrect and would trash the bearing in a short amount of time anyway. Could be there was a burr or crap in the bore or maybe the fit was altered because someone was beating on it with a hammer and had a whoops? To need so much pressure that it would bend the ears would mean the the cap would have to deform and most likely eliminate the running clearance in the bearing.

Every bearing has a designed fit. Some are intentionally baggy... some tight... some with built in clearance for allowance of a press fit in a bore... and some with even greater allowance for press in both bore and on shaft. There are hundreds of prefixes and sufixes that can be applied to a bearing part number and all of them mean something.

[averagef250]

Automotive U-joints are sloppy loose things made by the billions. They are not 000 class Timkens. Automotive class bearings are bottom barrel crap.

I have a machine shop. Part of making stuff is keeping your machines going. I know how to work with precision bearings.

A quality lathe or mill spindle is sitting in some big buck bearings, very carefully installed and temperature controlled or compensated. That spindle can take huge shock loads and side forces without any ill effects on it's bearings.

I find that stuff about hard spotting very difficult to swallow. That's not the real world.

[Madman]

You wont bend the ears in a vice using the sockets as spacers, but I'd have to have a picture to clearly show how they go. It is a very smooth process when done correctly, but whatever works for you.

For one, a vise isn't a press. For two just how do your magic sockets support both yoke ears while pressing the joint? You're only supporting one of the ears, not both.

I think the hammer method is something that's hard for someone who's never been around this kind of thing to grasp. It's the right tool for the job, but it takes using it correctly otherwise you get nowhere. A big nasty stuck U-joint is a 2 minute changeout max with a hammer and an operator with a clue.

I also wouldn't argue with the suggestion to take it to a good driveline shop. For your typical one piece automotive shaft the shop I use charges about $70 for disassembly, hot tank, new joints and balancing.

Sorry you can't do anything but beat the hell out of something, but it works, and twenty plus years experience as a auto mechanic, machinist, and heavy equipment operator says it works just fine for me. You don't like what I say, don't listen, but don't tell me I'm wrong, because you have a narrow scope of view.

[PhantomoftheBumpside]

You can bend the yoke with a hammer. You can't necessarily see it's bent if it's only slightly bent.

Hardened metal objects like needle bearings, trunnions, trunnion bearing caps and hammers can, and will, chip and crack. When you chip internal pieces from too much slamming you get a condition known as spalling.

When u-joints are incorrectly installed, usually misalignment due to the yoke being uncleaned or bent (how many pro's know what an alignment bar is?), sometimes just too much beating on it, you can end up way too much contact stress which will lead quickly to the condition known sometimes as 'hard spotting' but more properly known as brinelling. That is the real world. It can also make some real noise.

If you don't have a vice to use with the hammer, you could use a jack to push the joints out of the yoke while the drive line is still installed. This is an old method used with big equipment. Line the yoke so it is up and down, and make sure you go slow, you are not trying to lift the truck here... Tap gently on the side of the yoke if the dl doesn't want to budge immediately.