U-Joint Replacement by Steve (a.k.a. Jeeper)

Note:  Steve was gracious enough to let me post his write-up on how to do a u-joint replacement.  This came right after a trail run where one of our friends suffered a rear drive shaft u-joint failure while attempting to climb a steep rock shelf.  I learned first hand how to do it, courtesy of the driver who’s drive shaft blew.  I hope you find this information as helpful as I did.

After recently removing my front drive shaft for inspection, I noticed that the U-Joint was in bad need of replacement. I’ve replaced U-Joints before while on the trail and I thought this would be the perfect opportunity to write-up the instructions using only the tools that I normally carry with me in the Jeep. So, here you go, a step-by-step guide to removing and replacing a U-joint. You can use these instructions on the trail or in the garage. These instructions are of course assuming that you have the correct U-Joint replacement handy.

1. Remove the straps that hold your drive shaft into the transfer case and pinion.
2. Carefully remove the shaft so that you don’t knock the caps off the exposed ends.
3. Use duct tape or electrical tape to secure the caps on the end that you will not be working on.

4. If you have greaseable U-Joints, mark the area with tape where the zirk fitting is in the yoke. This is important because if you don’t, you may install the new U-Joint in the wrong place and end up not being able to grease it or knocking it off when the yoke hits when spinning.

5. Install the zirk fitting in your new U-Joint. Why they don’t do this at the factory is beyond me. I use a 5/16″ deep well socket for this.


More U-Joint Replacement

U-Joint Replacement by Steve (a.k.a. Jeeper)

6. Remove the caps that are open. (the ones that are not seated in the yoke). All you need to do is pull on them and they slide right off.
7. Rest the yoke against something solid so that one of the two remaining caps are facing upward. You can use a rock on the trail or the back end of a vice in the garage.
8. Use snap ring pliers or needle nose to remove the snap ring that hold the cap in the yoke. Do this to both sides.

9. Place a 3/4″ socket on one of the caps and hit the socket with the BFH. Make sure that the yoke is back on the solid object before you do this and that the other cap has room to move out of the opposite side of the yoke.

10. Keep hammering until the cap breaks through to the inside of the yoke. This will force the opposite cap to move out of the yoke as well but not completely.
11. Remove the cap that you just hammered on by twisting the U-Joint until the cap is easily pulled out from the inside of the yoke.
12. Move the U-Joint around some more and the U-joint should come completely out. The remaining cap is easily removed by either your fingers or a pair of pliers.

13. Clean the Yoke with carb or brake cleaner and check to make sure that the yoke is in decent shape. Be sure not to remove the mark you made earlier indicating where the zirk fitting is going to be placed when you install the new U-Joint.
14. Line up the new U-Joint so that it will fit in the yoke, making sure that the zirk fitting is in the proper place.
15. Remove the appropriate caps careful not to loose the needle bearings.

U-Joint Replacement
by Steve (a.k.a. Jeeper)

16. Insert the U-Joint into the yoke.
17. Place one cap at one end and move the U-Joint into the cap so that you don’t shift or lose the needle bearings.
18. Place the Yoke back onto the solid object and tap on the new cap with the BFH while making sure that the U-Joint stays within the cap you are tapping on.       You do not need to pound it completely in place.
19. Turn the yoke over and place the other cap into the yoke and lightly tap it with the hammer so that you don’t lose the needle bearing on this side.
20. Use a “C” clamp to compress both caps into place.

21. You will need to use the socket and hammer to seat them properly so that you can install the new snap rings.

22. Install the snap rings. A flat head screwdriver helps to make sure that they are in their proper place.
23. Install the drive shaft the opposite of how you took it out!

Tools used:
1. Tape (duct or Electrical)
2. Snap ring pliers or needle nose
3. Flat head screw driver
4. socket
5. BFH  (really big hammer)
6. C-Clamp
7. 5/16″ deep sell socket
8. cleaner

Well, I am by no-means a mechanic so if some of you reading this see something I missed or can explain it better, please feel free to do so. All in all this was about a 25 minute job and that included taking notes and snapping pics.

Hope this helps!


Always Check it Out!

My buddy, Robert, from California, was over during Easter to do a little wheeling and enjoy Arizona.  I had promised him some good trails and while fulfilling that promise, I managed to put a dent in my front drive shaft. (rock + drive shaft = dent)
The local drive line shop came highly recommended by the local guys, so I dropped my drive shaft off in hopes of getting by with a simple (read cheap) balance job.  Unfortunately, the phone call I got later that day informed me that it needed to be re-tubed (a new center tube installed).  I told them to do it and went down later in the afternoon to pick it up, after they had called to say it was done.

As most folks know, it is common to put a couple wraps of tape around the end caps on the u-joint so you don’t loose them. This had been done to the u-joint on the diff end of my newly rebuilt drive shaft. I didn’t think anything of it, and I would have been concerned had it not been done.  I gave the drive shaft a once over, paid for it, and was on my way.

The following Saturday, I begin the install of the drive shaft and unwrapped the tape so I can slip the u-joint into the yoke. Hmmmm…..that is funny. Where did the gouge on the end cap come from? That wasn’t there when I took it in to have it worked on.

I pulled the end cap off to get a better look at it and that is when I noticed that three of the needle bearings where missing. OK….I can see the scenario now…..employee working on my drive shaft drops it….enough to gouge/dent the end cap. The end cap pops off (we have all had that happen no doubt?) and some of the bearings go flying around the floor.

What ticks me off is that they didn’t even pony up to the table and tell me they screwed it up (I would have expected that at the very least and thought a repair on what they screwed up would have been the norm, based on how everyone praises this place.)

I’ve not contacted the shop to hear their side of the story. I find it extremely difficult to think that they could have gouged the end cap and lost some of the needle bearings and NOT have realized they had done it. I don’t expect it from someone that does this for a living….and I pay $100 for the work.

So….the lesson is to be sure to check out item when you pick it up.  I made the mistake of looking at everything except what was hidden under the tape.  

U-joint Inspection

“I’ve got over 130,000 miles on my TJ.  Do you think I should do something with the u-joints in the front axle?”   This was a question I was asked just the other day.  My answer was “YES, REPLACE THEM!”

“But they look just fine.”  My answer….”I don’t care, replace them anyway.” 

How do you know when that u-joint is bad?  Is it about to go….will it go the next time out on the trail?  Who knows?  No one really does, but you can play the percentages a bit and figure out when it may be time to take a look at the u-joints on your vehicle.  I do know that doing u-joint maintenance in in your driveway is ALWAYS the preferred location, especially when one thinks about the hassles involved with doing u-joint replacement out on the trail.  (some folks are well prepared for this but most folks do not) 

U-joints do not last forever.  Your use of your vehicle….easy trail driving, muddin’, rock crawling, or just a bit of 4WD for those winter roads, will have varying affects your u-joint life.  Water crossings can wash away the lubricant and introduce contaminants into the needle bearings.  When that happens, the needles grind themselves into dust and your u-joint fails. 

Here is a photo of a Spicer 5-760x u-joint that came out of my D30 axle after having been in use for almost 40 months.  The grease has lost all of its lubrication quality.  The needle bearings are pretty much frozen in what ever it is that is left of the worn out grease….probably a mixture of grease and dirt.  There was just a hint of rust forming in a few places.  Of the other three caps, one was almost this bad and the remaining two had enough lubricant in it to continue doing its job for a while. 

You can see the hint of rust starting to form in the bottom of the cap.  This one would not have lasted much longer before the needle bearings started to grind into red dust.  I’ve opened up a cap or two where dirt/dust has come out.  Amazingly, the u-joint had not broken nor had the cap rotated in the yoke ears. 

On the right is a cap taken from a brand new Spicer 5-760x u-joint.  The lubricant is “alive and well” and looks like grease to me.  Quite a bit different than the “used” one on the left. 

My goal here is to make you aware of an important issue, that being routine maintenance for your u-joints.  Your front and rear drive shafts have u-joints as well and require periodic maintenance.  I suggest you set up a schedule and routinely examine your u-joints.  Having a few spares on hand before you inspect them would be a good idea.  If you find a bad one, replace it….and while you are at it, replace the other one too.  Then you can reset your inspection clock and both axle shafts will come due again at the same time.