CONGRATULATIONS,

YOU HAVE JUST PURCHASED THE BEST OF THE BEST!

I’m sure by now you have changed quite a few U-joints and are pretty good at it, HOWEVER please read all of our tips and procedures prior to install. A proper installation will make the difference between a joint that lasts years or one that fails in a few months.

If you read no further - remember these 3 things!

    1. Cleanliness. Install them as clean as if you were installing a set of rod bearings in your motor.

    2. Full circle snap rings go on the cross prior to installing the cross in axle ears.

    3. After installing, if there is any bind up in the joint - it will fail.

OK let’s get started:

1. Do not open the small-parts bags; there is a lot to do prior to the actual install and there are too many small parts to lose.

2. If not installing in new shafts, disassemble your axle shafts, and CLEAN them in solvent. These need to be as clean as if you were installing rod bearings. Standard u-joints have needle bearings in them and if a little grit gets in there it will find a place between the rollers and function ok for a long time. Since there is only .002” clearance between the bearing surfaces in the Jantz Joint there is no room for any contaminants.

3. Inspect for dings inside the cap bores. These dings are in almost all used axles as the cross hits the ears when pressing out the caps. These dings must be carefully filed away to prevent the cap from being distorted out of round and pinching in on the cross. It does not take much of a ding to use up the .002” clearance between the bearing surfaces.

4. Inspect your axle for proper dimensions, often when pressing the caps out the ears get bent in or out a little. The correct dimension between the ears is 2.188” plus .010” minus zero, and should be checked in several places

5. If you do not have calipers put two of the full circle snap rings on the caps and check for sufficient clearance. You should be able to get a .012” feeler gage between the ears and the snap rings, but a .020” should not fit. As you can see our used outer axle had an ear pinched in about a 1/16” . and the after market axle fit just fine.

6. If the ears are bent, a little adjusting with a hammer will bring them into specs. It will take a good eye to determine if one or both ears are bent. Hold axle exactly vertical using a vertical line in the distance (like a door frame) and eye which ear is not vertical prior to adjusting.

7. Now that the axles are prepped and CLEANED, lay out the small parts and install the big O-rings inside the caps and the little O-rings onto the pistons, and grease very lightly, BE CAREFUL NOT TO LOOSE THE GREASE ZERKs , they are very small, and will not be installed for a while.

8. Place a layer of supplied grease inside the cap. Greasing the trunion now is a waste of grease as the o-ring will wipe it off while the cap is being installed.

9. IF YOU ARE USING FULL CIRCLE SNAP RINGS PLACE THEM ON CROSS NOW! Standard crescent snap rings can be installed later but the full circle ones cannot.

10. You will find it easier if you install the cross in the short axle piece first, as it is easier to maneuver the short axle and u-joint into the long axle later. Notice the chamfers and the recesses in the cross, Install chamfers down. The pictures show the right and wrong way.

11. Next place a light dab of grease onto the tail of the piston, to hold it in place during assembly.

12. Place spring and piston into bore. Note: the bores are not cross drilled, each cap has its own separate grease reservoir, and DO NOT fill the piston bores up with grease prior to assembly, or the spring will not compress later.

13. Drive in the cap with a hammer and suitable socket. NOTE: DO NO USE A PUNCH OR HAMMER DIRECTLY ON THE CAP OR IT WILL DAMAGE THE GREASE ZERK HOLE. A socket or a piece of tubing will hit around the zerk hole.

14. Now install the piston and spring on the other side. (I wish I had a nickel for every time I left these out and had to press everything apart and back together again.) Well at least you don’t have to worry about dropping needle bearings with these joints.

15. Now drive in the next cap as in step 13 above.

16. Install the snap rings on two caps. NEVER use a punch to install the snap rings in the grooves, if they will not go into the groves with your fingers SOMETHING is out of place. Recheck clearances as shown in steps 4 & 5 above. It may be necessary to “set” one of the caps snap ring against the axle ear before there is room to install the 2nd snap ring. Striking the axle as shown will drive the axle ear down around the cap, in effect moving the cap out as far as possible. Notice the position of the other axle shaft just setting on the vice. This method moves the axle instead of the u-joint and works better because you are moving one cap at a time rather than trying to move both caps with hammer and socket.

17. Now you are ready to join the 2 axle shafts.

18. IF YOU ARE USING FULL CIRCLE SNAP RINGS PLACE THEM ON THE CROSS NOW! Standard crescent snap rings can be installed later but the full circle ones cannot.

19. Install the pistons and springs again.

20. Install the next cap.

21. Repeat steps 18 & 19

22. Install the remaining snap rings.

23. “Set” all 4 snap rings against the ears. Usually when doing U-joints you hold the axle and move the U joint but in this step you hold the U joint and move the axle. This will in effect move each cap individually up against the snap ring providing proper end play for the cross.

24. CHECK FOR BINDING - the axle should move freely in all directions. To check for binding lay the long axle on a bench and roll it slowly with the short axle over the edge. The short axle should always fall down at about a 40 degree angle, If the short side does not fall down freely under its own weight SOMETHING IS BENT OR BINDING and will cause premature failure if not fixed.

25. Install zerks using a 5/32” punch so that they are slightly recessed into the cap. Do not hit the zerks to hard as they are easily damaged.

26. Clean out grease gun; wipe out all excess grease and insert the supplied cartrige.

27. Pump several times to clear out old grease from gun.

28. Install needle tip greaser to gun.

29. Pump several times to purge needle tip of air.

30. WARNING! Grease guns put out several thousands of pounds of pressure. The O- rings used in the U-joint will blow out at around 1000 psi. You are probably accustomed to standard u-joint seals where you pump until grease is coming out of all the seals. DO NOT DO THIS WITH THESE JOINTS. Instead slowly pump grease into each cap. The grease gun handle should move gently. As soon as you feel resistance, STOP PUMPING! The piston has bottomed out the spring and you now have 300 psi of grease inside to prevent any water or dirt from getting inside.

31. Solvent wash any excess grease off caps and place a swatch of tape over the top of each zerk to keep it clean. NOTE this grease is tenacious. Most solvents will hardly remove it, but to brake fluid (new or used) works very well and then most any solvent will clean up the brake fluid.

32. As the joints are used, the grease will slowly work its way out past the o-rings, giving a constant supply of new grease to the bearing surface and pushing out dirt and wear particles.

33. Greasing the U joints 4 times per year should be sufficient. Place a new patch of tape over the zerks each time.

Jantz Joint

    --- Vs. ---

        OEM

             90% stronger than OEM joints

1. Trunion size increased

    A. yields 72% Strength Increase

    B. Eliminates needle bearings which crush and disintegrate during extreme use

    C. Eliminates needle-bearing lock up, which typically destroys
         the axles and U-joints by rotating the snap rings and caps out of place.

2. 4340 forged material (25% Strength Increase based on OEM joints)

3. Ionically bonded coatings

    A. Eliminates need for bearings or bushings

    B. Prevents gauling from metal to metal contact

    C. Eliminates the need for periodic rebuilding compared to other Aftermarket U-joints.

    D. Allows trunion size on DANA 44 U-joints to be larger than the DANA 60 OEM trunion.

4. Pressurized grease reservoirs

    A. Each cap & trunion has its own 300 PSI-grease reservoir to replenish grease as it is consumed.

    B. The pressure keeps out water and debris that are normally
      sucked into OEM joints during water crossings, deep mud, and pressure washing.

    C. Being able to grease each cap prevents the usual from happening, which is grease is pumped in
       one zerk and only comes out 3 caps leaving the 4th starved for lubrication.

5. Unique cross & trunion periphery

    A. Allows larger cross section to be installed in small yoke configurations without using a multi-piece cross design.

    B. Moving the shear planes out lessens the stress significantly

6. High Temperature copper & Graphite EP compound

    A. Finely divided soft metals & solid lubricant prevent metal to metal contact under 200,000 psi loads.

    B. Will not break down in temperatures up to 2000 ° F.

    C. Creates a work hardened copper bushing between cap and trunion substrates

7. Patented design (Prevents others from copying unique features.)

8. Full circle snap rings prevent caps from working out of axle cups.

WHY YOU NEED THIS JOINT!

Jeep Rubicon STRESS CALCULATIONS:

The new Jeep Rubicon will break the OEM front axles U-joints for the following reasons. A 30 spline alloy axle has a max rating of 6200 ft-lbs. From years of empirical DATA, typically the front axle joint fails prior to the front axle breaking. Thus the capacity of the OEM Joints is less than the 6200 ft-lbs.

Now compare this to the torque output of the Jeep Rubicon. The motor produces 235 ft-lbs. of torque, which is then multiplied through a 1st gear ratio of 4 to 1, plus a transfercase with a 4 to 1 ratio, plus a rear end ratio of 4.10 to 1. Even with frictional losses this calculates out to 14,000 ft-lbs. of torque. And since the Rubicon has air lockers all this torque can be applied to only one wheel if the others lose traction.

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