Double Cardan Rebuild

[PassRunnerZJ]

This build or rebuild was brought on by my ZJ having that constant squeek when driving and it has 159k miles, I narrowed it down to the front drive shaft by removing it and the squeek went away I figured it must be time to rebuild the double cardan (DC) since replacing the front u-joint didn’t do anything to solve the squeaks. Here goes...

Parts needed:
Three (3) u-joints to fit your application – yea I know you only really need two, but if you mess up it is good to have a spare and you should have a spare u-joint anyway
One (1) Center yoke support kit with either the one with a dust cover—not recommended by the driveline shop I picked the parts up from OR the needle zerk greasable one w/metal splash ring

List of tools I used:
8” or so vice
Various sockets to push and allow caps to slide out of axle ears (same as you use to change a u-joint)
Hammer
Safety glasses
Small screwdriver
Medium screwdriver
High Lift Jack handle – more leverage on the vice
Needle nose pliers
Vice Grips
Penetrating oil
Grease gun w/needle adapter

[PassRunnerZJ]

• Mark/scribe each end of the driveshaft so you can put it back on in the same way it came off
• First remove the drive shaft if it isn’t already off the Jeep
• Apply a wrap or two of blue painters masking tape around the open cap ends of the front u-joint
  • Compress the drive shaft and clean up the grease that comes out of relief hole so that it will be less of a mess later
• Clean up the loose dirt and mud
• Soak the caps with some kind of penetrating oil for a day or longer if you have time – this saves a lot of time and frustration during the disassembly process
• Scribe side of the DC “H” to drive shaft so that you can realign everything when you put it back together
• Start by removing the u-joint that connects to the transfer case like you would for a normal u-joint on the “H” part of the DC
  • Using a socket a little smaller than the size of the cap apply pressure in the vice or press to break them free
  
  
• You can’t push the cap out as far you normally can on a single u-joint due to the binding that the center yoke causes

• Use your Vice Grips to turn and pull the cap off the end that is sticking out

[PassRunnerZJ]

• Once this is off use a smaller socket on the shaft of the u-joint to push it back the other way and out the other side

• After both caps are off the “H” you can remove the yoke by turning the u-joint so that each end without the caps comes out

[PassRunnerZJ]

• Put the yoke out of the way
• Remove the second u-joint from the H” in the same manner that you removed the first one being careful not to drop it or anything else on the center hub of the yoke bearing

• Now remove the u-joint from the axle part of the DC as you would any other u-joint
• Remove the old rubber dust cover from the center support bearing part of the H
  • Work a small screw driver around the circumference of the dust cover getting it between the metal on the back of the cover and the metal of the center yoke support with light taps from a hammer, it should pop off as you are working around it
  
  
  

[PassRunnerZJ]

• Clean the dirt and old grease from the center support bearing including the hole where the spring goes in
• Press the center yoke splash ring keeping the beveled end towards the center bearing support unit
  • I used a large socket and hammer without any problems with easy blows

[PassRunnerZJ]

• Clean up the insert area for the u-joint caps and I applied a thin layer of grease
• Remove the caps to the u-joint and add a healthy amount of grease in the cap to the bearing and pack them in with your finger
• Push the first cap in on one side of the axle u-joint ear about half way
• Insert the u-joint to the first cap
  • Make sure that your zerk hole points toward the driveshaft and the axle ear rotates towards the zerk

This image for reference of zerk hole, don't install the zerk until you are done

• Seat the cap even with the ear of drive shaft or a little more
• Start the second cap by hand and if it goes in far enough slide the u-joint part way into the second cap without taking it all the way out of the first one
• In the press seat the second cap
• Install snap ring on one side, then push the other side over until you can set the other snapring
  • If you can’t push it over enough to install the opposite side snap ring odds are that a pin dropped. Take the time to push it apart and replace the bearing if you put a lot of pressure on the caps.
• Once the snap rings are installed check for proper movement, it might be a bit tight but it will loosen up as the centrifugal force pushes the caps out
• Now the fun starts
• Work the H around the shafts of the u-joint with banging u-joint’s axle surface
  • Make sure that the support bearing shaft is pointing away from the drive shaft and installed u-joint
• Start one of the caps into one side of the H and slide the H onto the u-joint
• While holding the H and cap on the u-joint press the cap into its seat
• Turn the axle over and insert the other cap in the other end and slide the u-joint and drive shaft into the cap without taking it all the way out of the other cap to avoid dropping a bearing
• Seat the caps and clips, same as above

[rccolacc]

What is the part number of that center yoke support kit? How much did it cost? I broke the ear off of mine when I was replacing a u-joint not long ago. I was dreading replacing it because I thought the dealership wouldn't sell it alone. I figured they would sell it with the whole driveshaft.
Good article. Wish I used a vice to take the u-joints off. Heavy blows with a ballpeen hammer and sockets work, just not as well. I wish I wasn't a poor college student....
-RC

[PassRunnerZJ]

• Yoke time
• Open the needle zerk on the outside of the yoke and pre-grease the bearings while holding the rubber cap over the spring that holds the bearing in

This image is to reference the needle zerk you should use, you are not at this point yet

• Note: Make sure the other needle zerk in the center of the yoke is closed as there isn’t any access to this after it is assembled
• Remove the caps from your second u-joint and pre-grease them like you did earlier or with more grease

[PassRunnerZJ]

• Remove the rubber cap from the center of the yoke and transfer the spring into the spring hole in center of the H
• Put two caps on opposite ends of the u-joint and put it into the yoke
  • Make sure that the zerk hole points towards the transfer case end of the DC and that it is offset on the same side as your other zerk (At least this is what I found as to how to do it)

• Carefully put the yoke on without dislodging any bearings in the center of the yoke
  • Now you have to keep pressure towards the drive shaft as the spring is pushing it away
• Insert a cap on one end of the H and push it place most of the way to full seat without jarring it
• Now carefully insert the u-joint into the cap

• Press the cap in past where the clip goes in to hold this cap on
• Turn the drive shaft so that the last ear is pointing down and start the last cap
  • If you have to turn it on its side there is a much greater chance of a bearing falling
• Carefully, really carefully slide the u-joint down keeping it lined up straight into the second/last cap without dislodging a bearing all the while pushing the yoke in to the drive shaft
  • Here is where the extra u-joint comes in, at least for me as I lost bearings on both ends and had to redo them – practice makes perfect, correct?
  
  
• Now seat the final two caps and install the clips the same as you did for the above u-joints
  • Again, if the caps don’t seat far enough without a lot of pressure to insert the clips you have dropped a bearing
  • A tell-tale snap while applying pressure is another sign

• Now clean up as much grease as you can the came out of the zerk holes when you installed the caps
• Install the regular zerks and tighten them down
• Grease each zerk until grease starts leaking from each seal and grease the center yoke needle zerk until a good amount of grease come out the relief hold on the TC side of the DC
• Tighten the needle zerk and double check each zerk
• Twist the u-joint in all directions as much as you can to verify full articulation and move the grease around
  • Note: Make sure your fingers are outside of the DC unit before you start turning it
• Re-grease zerks and check for tightness
• Install the repaired drive shaft on your rig taking not of alignment marks and aligning it to those marks
• Double check bolts and nuts
• Grease the zerk on the drive shaft for the shafts compression, it will take a quite a few pumps as you probably pushed all the grease out earlier when you were working on the DC
• You should be done now and ready to take it out for a test drive
• Don’t forget to double check the tightness of your bolts and nuts as well as making sure each u-joint still has cap clips after 50 or so miles.

[PassRunnerZJ]

Originally Posted by rccolacc

What is the part number of that center yoke support kit? How much did it cost? I broke the ear off of mine when I was replacing a u-joint not long ago. I was dreading replacing it because I thought the dealership wouldn't sell it alone. I figured they would sell it with the whole driveshaft.
Good article. Wish I used a vice to take the u-joints off. Heavy blows with a ballpeen hammer and sockets work, just not as well. I wish I wasn't a poor college student....
-RC

Part numbers for Spicer components (prices are from my local Drive Train Industries):
Yoke - 211544X ~ $65.00
Yoke Splash Ring - 231864 ~ $6.00
U-Joints - 5-153X ~ $12.00

Yes, being a poor college student is tough, but once you get done it will be worth it. I think that the dealership would sell you the Spicer components, but the price might be higher than a driveline shop or NAPA. -Todd

[jsteves]

nice writeup...but wow, I can't believe they charged you that much for the centering kit. I went into my local driveline shop to buy the same parts, for $60 they gave me all the parts, and installed 'em.

[PassRunnerZJ]

Originally Posted by jsteves

nice writeup...but wow, I can't believe they charged you that much for the centering kit. I went into my local driveline shop to buy the same parts, for $60 they gave me all the parts, and installed 'em.

Thanks. Sometimes it sucks to be in Grand Junction and with less than four days before a scheduled trip to Denver for my son's soccer match I didn't have time or want to chase parts for a few $$ saved and DTI is a couple of blocks from work.

On the other hand, I'm only two hours away from Moab, less than two from Gold Metal Flyfishing... Napa wanted $45 for a non-Spicer kit here and I think it was the rubber bushing one that is not greasable, but I didn't want to go down that road with a DC rebuild. -Todd

[jsteves]

mine was rebuilt with spicer parts as well...like you said, the ups and downs of grand junction

[nate]

Yeah the last centering kit I bought was around $35.

[zj-monster]

Sweet write-up!!

In fact, this needs to be moved to the FAQ's and Write-Ups thread.