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Yukon Super Joint Install
Yukon Gear and Axle


Yukon Super Joints Kits - For the ultimate in U-joints, these kits come with 2 joints, grease, grease gun, instructions, clips and zerk fittings.

For people looking for the ultimate in off-road performance, Yukon performance offers two different super strong axle u-joints.  The cross sections of the "Super-Joints" are made from forged 4340 Chrome-moly, through hardened for the ultimate yield and tensile strength.  After hardening, the cross section is then coated with titanium nitrite. This coating provides an extremely hard surface to protect against wear. The caps are made from cold extruded 4140 Chrome-moly.  After being formed they are then induction hardened to provide maximum strength without becoming brittle.
This patented design doesn't utilize needle bearings so they rely on offset harnesses to protect against wear.  The caps will wear out first and can be replaced at a lower cost than buying an entire new u-joint.  Yukon offers a lifetime warranty against breakage of the CROSS SECTION ONLY on all super joints.

Installation Instructions

First things first: the Super Joint is unique. Even if you have changed quite a few U-joints and feel you are pretty good at it, please read all the following tips and procedures prior to install. A proper installation will make the difference between a joint that lasts a long time or one that fails prematurely.
1.   If not installing 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 so should a little grit get in, it will find a place between the rollers and function okay for a long time. However, since there is only .002” clearance between the bearing surfaces in the Super Joint, there is no room for any contaminants.
2.   2 Next 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. The dings must be carefully filed away to prevent the cap from being distorted out of round, and therefore pinching in on the cross. It does not take much of a ding to use up the .002” clearance between the bearing surfaces.
3.   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 2.193” plus or minus .005”, and should be checked in several places (fig. 1).
    If you do not have calipers, (fig.2) put two of the full circle snap rings on the caps and place the caps on the cross of the U-joint to check for a snug fit.
4.   If the ears are bent, a little bending with help from a vise will bring them into spec. It will take a good eye to determine if one or both ears are bent.
5.   Put supplied anti-seize grease into the grease gun. Install the needle tip greaser onto the grease gun. Pump several times to purge needle tip of air.
6.   Place a layer of special anti-seize grease inside the cap as well as filling the lubrication reservoirs in the main cross of the u-joint. By filling these reservoirs it allows the u-joint to self-lubricate between regular maintenance with centrifugal force.
7.   If you are using full circle snap rings, place them on the cross now. Keep in mind that standard crescent snap rings can be installed later, but full circle rings cannot. Notice the chamfers and the recesses in the cross. Install chamfers down. [The pictures show the right way (fig. 5) and the wrong way (fig. 6).]
Fig. 5 - Right Way
Fig. 6 - Wrong Way
8.   Drive in the caps with a hammer and suitable socket. NOTE: DO NOT USE A PUNCH OR HAMMER DIRECTLY ON THE CAP AS IT WILL DAMAGE THE GREASE ZERK HOLE. A socket or a piece of tubing will hit around the zerk hole.
9.   Now that the caps are installed you can install the snap rings onto the caps.
10.   Next, you will need to set the snap rings. To do this, place the axle assembly in an open vise, or a U-joint installation jig, and firmly tap the yoke, forcing the U-joint caps outward. This process secures the snap ring, and allows the U-joint to move freely (fig. 7).
11.   Now you are ready to install the zerk fittings, these fittings should be installed reasonably tight with a 7mm nut driver. Be careful not to over tighten and strip the threads.
12.   You are now ready to grease the zerk fittings.
13.   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 Ujoint 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. The purpose of this is to prevent any water or dirt from contaminating the U-joint.
14.   As the joints are used, the grease will slowly work its way out past the O-rings, providing a constant supply of new grease to the bearing surface, and pushing out dirt and wear particles.
15.   Greasing the U-joints four times a year should be sufficient, but it may be necessary to grease heavier-used vehicles more often.

All information listed on these tech pages cannot be guaranteed to be true or correct. Please be sure to
consult a verified source before moving forward with any modifications based on the knowledge found here.
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