How hard is it to replace a u-joint? The rear u-joint on my truck is in BAD shape. IE: Loud clunks when shifting, highway vibration, and at least a half-inch of play when I grab the driveshaft and wiggle it. It's over a hundred bucks for the shop to do it and that seems ridiculous to me. Is this something I can do in the driveway fairly easily or do I foot the bill for a mechanic?

Chris Pollard
Dryden, ON
Don't mind me, I'm crazy.
:-X11

 

Hi Chris, how is Dryden? I lived in Thunder Bay for 5 years and really miss it out there.
Anyway, U-joints are pretty easy especially the rear one. If you are near a vice than the job is even easier.
Just pull out all the lock rings and spray a little wd40 around. Then pull of the 2 end caps that you can get at. Then open the vice up so that you can put those 2 ends that you just took the caps off on to the top of the vice, you will now carefully be knocking the top the driveshaft as close the the snap ring hole but not on it. this will drive the shaft down and displace the joint. Reverse it for the other end.
I do not like to tell people to do it this way but not alot of folks own a ujoint press. Please be careful when hitting the shaft because if you hit too far down you will dent it and that;s it ....new shaft coming. Just hit it enough to pull the cup through...hope all this helps or gives you some idea.

 

I put the yoke in the vice between two sockets. One big enough so the cap can slide into it and the other small enough to fit into the end of the yoke and sit against the other cap. As the vice is tightened it presses the U joint into the larger socket, remove the cap and press it the other way to get the other cap off. In the days before I had a vice, I used the same theory except I used a small sledge hammer to drive it out.

 

The vice, single socket, & hammer method worked for my front U-joint yesterday.

I took the C-clips out, sprayed PB (Parts Breaker) & allowed that to soak in over a day (highly suggested - don't expect a good penetrating oil to do its job in a small amount of time).

Took it to the vice and pushed the slightly-smaller diameter impact socket through to push out one side. Eventually I think i had to push it the caps the other way, then back again to loosen it enough to yank it out with vice-grips.

Not too hard, but I had the tools and a very nice-sized vice.

Now let me tell you about my rear U-joint...

I did drive on it after it went bad for about 110 miles (65 MPH or under, carefully, with lots of vibration)...

I got one set of caps to budge a little, but then it was pretty much a no-go situation. A really good mechanic tried with hammers and a vice, still nothing.

After a real good amount of wasted time getting nowhere, we took the driveshaft and the connected (via the U-joint) yoke outside and used an acetylene cutting torch on the main body of the U-joint. The U-joint body melted & cut nicely, then we knocked the caps toward the inside with a hammer. Had to be careful to not directly heat the driveshaft or yokes though. Still, they both got really hot in the process.

Use a little fine sandpaper inside the holes to smooth & clean 'em out, grease 'em, then install the new caps & joint.

Best,

 

[updated:LAST EDITED ON 02-Aug-02 AT 11:31 PM (EST)]okay guys i need a hand here. i understand what you are all saying about using a vice, but do i need to take the driveshaft out and if so how go i get the driveshaft out and to the vice? thx

 

[updated:LAST EDITED ON 02-Aug-02 AT 11:52 PM (EST)]Not too sure what truck you have, but here's how I pull my rear driveshaft:

At the end that connects to the differential there are four bolts that you'll need a (err... what is it?) sixteen (?) point socket for - the size may be around a 13mm or 14mm.

I think I was told to mark the driveshaft to the yokes, and to the differential, to make sure I put it all back the same way it was lined up from the factory. I tried this with paint once, but have since ignored it.

These bolts are surprisingly not too torqued down, so remember how they felt to pull off (the force you apply at the end of the wratchet handle) for when you tighten them back on if you don't have a torque wrench. (I think I use a good long-handled wratchet, a very short extension, and the socket to get at 'em)

Next use a pry-bar (or something) to get behind the plate (connected to the yoke of the driveshaft) you just unbolted and the differential's plate. The goal here is to unstick the driveshaft off of the differential by moving the whole thing a bit inside the tranny. Once you move the driveshaft just a little bit toward the front of the vehicle (or once you 'unstick' it from the differential), it will fall - *BANG!* - onto the floor (or you). You might want to prevent this by being ready for it.

Once that end is apart, the whole driveshaft can be slipped out of the tranny - and there you have it - tranny fluid on your floor... so put a catch basin under the tranny, or have the rear end of the truck jacked up to try to keep the fluid in the tranny.

When pushing/hammering out (or in, I guess,) non-OEM-Ford U-joints, many times they will have grease fittings in them, and these should be taken out (or left out) to allow the U-joint to slide its full amount within the space it has. Replace the grease fittings once the U-joint is totally centered back in its place.

Another thing I like to do - When pulling off, or putting on, the U-joint caps, I take my time and do each with the open-end of the cap I'm playing with facing up. This is an attempt (weak, perhaps) to get gravity to not be such a factor in keeping all those needle bearings lines up inside each cap.
Furthermore, I'll try to fill up the cap (gently) with grease to try to prevent the bearings from falling toward the inside.

The only mechanic I know who I've talked to about screwing the bearings up said he must have had some come out of alignment as he was putting a cap on once, and he had to hammer the cap on. He ended up changing that then-new U-joint only six months later. The good thing is that once you do one or two, you get the hang of the process - so screwing up and re-doing it six months from now (if that's what happens to you) really won't be as big of an issue on your mind.

 

I am having a problem instaling my u-joints. I got them out pretty much with no problems. I when to put the new ones in and I can get the cap on one side in fine and put the lock clip on. But then when I got to put the adjasent cap on I can't get it to go on enough to put the lock clip on. You can see there is enough room for the cap to slide down a little more so it fits on he joint it self. It seems like it is hydrolicing on my. The grease fitting is out. I tried this in the vise and suing a socket and hammer and it just pushes the other cap down and pops off the locking cap. What am i doing wrong? This has happend to me 3 of 4 fifferent times now and its so frustrating to me. Thanks for the help.

Jeff

 

Well, if the locking ring is porperly seated in its recessed area, what you're doing ought to be mighty hard to do. Most times when I get the locking clip in place I have to push it in (around its circumference) to get it to seat in better.

But that isn't your problem.

Your problem may be fallen, or ever-so-slightly out of place needle bearings. This is the part that one has to be the most careful for when installing caps, and its why I install caps with the open end facing up after I ensure all bearings are firmly seated against the inside wall of the cap.

If this is what hppened you may have messed up a needle bearing in your installation attempts. Clean out the cap that won't go on,and make sure all needles are there, that there is grease to keep the bearings sticking in place, and that all are seated properly. Any big nicks or bent needles may mean something bad...

When pressing in an opposing cap, I'll slide the u-joint body over to it, and into it, to try to keep the bearings from moving much. Of course the u-joint body has to be centered really well for it to fully slide in to the cap (often times the u-joint body will want to sit at an angle since there isn't much holding it in place).

I hope some of this helps you. Whatever you're facing, it most likely isn't hydraulics. The caps' end seals are made to allow grease to flow past them (outward) when we put new grease in through the fitting, so these seals won't cause enough of a hydraulic effect to push the other cap out. So I would guess that the needles in one of the two opposing caps need some tender loving care.

 

oops - also, the end-clips should not be put into place until two opposing sides (two end caps) are both installed and centered. Pushing the second one in a bit too far is a very common occurance, so you'll want to leave the clips out to push it back (and forth?) again until you're satisfied that they're centered and that you can get both clips in.

What i'll do is to get both caps in, then try to center them, then try to install the clips. One may go in while the other may not - so then a lighter pressure (or, really, a careful movement of a small amount) with the vise is needed to push the end you can't get the clip in to over a bit. The clip you did install will stop the U-joint from moving too far. Now install the second clip.

 

I took a look at the ujoints again took them out carefully. After I got them out I looked in the caps and on the sides that wouldn't go in properly the needle bearings had shifted. I followed what you said about putting them back in a using gravity in my favor and it worked. Thanks a lot, it was a big help.

Jeff

 

Wow, you had me worried there. Glad you got it together(!) - not really all that bad of a job, eh?

Do you think you messed up any needle bearings, or were they fine?

 

It wasn't a bad job at all after i figured out the best way to do it. Yeah i messed up a few needele bearings, broke some in half. I had a spare u-joint the was given to me and I looked at those needles and they were the same height and looked to be the same diameter, so took the broken ones out and replaced them with the spares and it works great.

Jeff