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straight And Narrow - welding Inner Axle Sleeves - Photo 39130633

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  • Sand or grind all of the paint away from the holes you drilled and weld the tubes in place. We used the HTP MIG200 with a flexible Swan Neck to weld around the circumference of each 1/2-inch hole, making sure to get good penetration between the outer and inner axletubes. You don’t want to simply fill the hole; you want a solid weld. Synergy also recommends welding the outer tubes to the cast-iron centersection with a TIG welder using stainless 312 rod and pre-heating. You can also do this with a MIG welder with pre-heating.
Sand or grind all of the paint away from the holes you drilled and weld the tubes in place. We used the HTP MIG200 with a flexible Swan Neck to weld around the circumference of each 1/2-inch hole, making sure to get good penetration between the outer and inner axletubes. You don’t want to simply fill the hole; you want a solid weld. Synergy also recommends welding the outer tubes to the cast-iron centersection with a TIG welder using stainless 312 rod and pre-heating. You can also do this with a MIG welder with pre-heating.
We started with a Synergy Suspension Jeep JK D30/44 Complete Inner Axle Sleeve Upgrade kit. For $200, you get the inner axletube sleeves, inner C gusset kit, and lower control arm skidplates. The ball joints are another weak point on the JK front axle, so we ordered a set of Synergy heavy-duty upper and lower ball joints (PN PPM-HD-BALL-JOINTS). Even with the cost of the ball joints, we think that our axle upgrade is a steal at $425. It may be easier to do some of the welding with the front axle removed from the vehicle, but we opted to leave ours in place in an effort to get everything done within one weekend. You’ll need to support the frame on tall jack stands and remove the tires to let the front axle hang free. If your JK has been treated to a salt bath during the winter, hose down the front end with a strong penetrating oil a day or so in advance. Remove the wheel speed sensor bolts with an 8mm Allen wrench. Gently, twist and lift the sensor out. It’s very common for these to break when you remove them, and they are about $15 each. It’s easier to snake the sensor through the backing plate once the unitbearing is loosened from the steering knuckle. The spindle nut required a 35-millimeter socket (a 13⁄8-inch socket works as well). Next, from the backside of the steering knuckle, use a 13mm socket to remove the bolts that thread into the unitbearing. Do not beat on the unit bearing to break it free from the steering knuckle or you can damage it. You’ll need to move the rotor and calipers out of the way. Use a 21mm socket to remove the caliper mounting brackets bolts. Lift the caliper off the rotor and hang it from the framerail with a wire hanger to make sure no strain is placed on the brake line. If the rotors are original, they will have Tinnerman clips holding them onto the wheel studs. Use side cutters to remove these, and pull the rotors off. You don’t need these clips when you reassemble the brakes. Here’s a cool trick for freeing the unitbearing from the knuckle. Thread the lower rear bolt until it is about 1/2-inch from being tight. Place a socket and extension on the head of the bolt and wedge it against the shock mount as shown. Now start the engine, and use the power steering as a hydraulic press. Slowly turn the steering wheel just a little bit, and the unitbearing will push out of the steering knuckle. With the shafts removed, cut the cotter pins off of the upper and lower ball joints and loosen the castle nuts. We are replacing the ball joints so we’re not concerned that the pickle fork will damage the rubber boots on them. A few good taps with the hammer should separate the two components. In lieu of the pickle fork, several solid whacks with a maul or heavy hammer on the inner C around the upper ball joint should free the knuckle. Leave one of the castle nuts threaded on the end of a ball joint to keep the steering knuckle from falling on the floor when it breaks free. For us, changing the ball joints was the most challenging part of this entire axle upgrade. We used a Pittsburgh Automotive four-wheel drive ball joint service kit (PN 4065) from Harbor Freight to press the old ones out and the new ones in. Even so, it takes an incredible amount of pressure, and an impact gun is less effective than a long ratchet handle and lots of grunting. To get the upper ball joint out, we used a short piece of 1 1/2-inch tubing (silver) in addition to the adapters included with the Harbor Freight tool. Removing the upper ball joint first lets you assemble the ball joint tool as shown to remove the lower one. While the upper ball joint is pressed upward for removal, you’ll need to press the lower ball joint downward in order to remove it. For this one, we only needed the adapters and spacers include with the Harbor Freight tool.
The Synergy heavy-duty ball joints are a serious step up in strength from originals. They are greasable and have a sintered-metal bushing design which is more robust than the factory ball joints, which actually have plastic in them. The originals wear quickly with 35s, and are prone to failure. For JKs with RCV axleshafts (such as ours), Synergy includes a low-profile needle-type grease fitting. Before installing the ball joints, remove the polyurethane boot and spring retainer. For the lower ball joint, position the hole for the grease fitting facing the front of the Jeep and use the tool to carefully press it in place. Make sure the ball joint goes in square and even. This will take a lot of effort. Work slowly and don’t get too frustrated. Press the ball joint in until the collar seats on the bottom axlehousing. Once you have the ball joint completely in, you can thread in the grease fitting and reinstall the polyurethane boot and spring retainer on the bottom. The upper ball joint goes in from the top, and getting it in just plain sucks. The bottom of the mounting flange in the axle is curved and the spacer won’t sit flat against it. After trying several methods, we found that using a couple of shims on the outboard edge of the spacer (shown) allowed us to press the ball joint into place. Make sure the shims don’t block the path of the ball joint. This looks scary and it is, but it was the only way we could get the ball joint pressed all the way in. Part of the Synergy upgrade kit for the JK are these weld-on lower control arm skidplates that help the axle to slide over rocks instead of get hung up on them and damaging the mounts. They are CNC cut and bent from 1/4-inch steel. They box and reinforce the thin factory brackets that normally bend or tear. If your brackets are already bent, you’ll need to straighten them so there is good contact all the way around with the skidplate. You need to drill eight holes in each axletube for the sleeve installation. Once the inner sleeves are in place, you’ll plug-weld them to the original axletubes through these holes. This makes for a very strong connection between the inner and outer tubes and an extremely strong complete assembly. Drilling the 1/2-inch holes is easier with the axle removed, but we were able to access the needed positions with a 90-degree drill. The 2-inch-diameter, 0.250-wall Synergy inner axle sleeve doubles the wall thickness of the factory axletubes. By welding the two tubes together in multiple places, you get nearly a 60 percent increase in strength. On an old axle, you may have to use an engine cylinder ball hone to remove the rust and scale from inside the axletubes before installing the new inner sleeves. Make sure you remove all of the debris from drilling. You’ll probably need to use a plastic dead-blow hammer to get the sleeves to seat all the way against the outer edge of the original tubes. Sand or grind all of the paint away from the holes you drilled and weld the tubes in place. We used the HTP MIG200 with a flexible Swan Neck to weld around the circumference of each 1/2-inch hole, making sure to get good penetration between the outer and inner axletubes. You don’t want to simply fill the hole; you want a solid weld. Synergy also recommends welding the outer tubes to the cast-iron centersection with a TIG welder using stainless 312 rod and pre-heating. You can also do this with a MIG welder with pre-heating. The upper and lower inner C gusset kit reinforces the ball joint mounts, making the assembly much more rigid and prevent the inner C from bending, which is a known issue with JK housings when used hard. We weren’t able to install them in time for this story because the aftermarket swaybar link relocation brackets sit exactly where the upper gusset needs to go on the axle. It’s a good idea to install these before you put the new ball joints in place to avoid possible heat damage caused by welding. We’ll do some trimming and modding and will eventually get ’em welded on. Finally, it’s time to put the steering knuckle, axleshafts, and brakes back in place. Assembly is simply the reverse of the disassembly outlined earlier. See the sidebar for a list of torque specs. Make sure that you grease your new ball joints before you hit the road. The Synergy joints come with new castle nuts and cotter pins. Between the Synergy axle upgrades and the RCV axleshafts we added previously, this Dana 44 front axle should be able to handle all but the most abusive off-roading with 35-inch tires. Best of all, we were able to make modifications over the course of a weekend and drive the Jeep to work Monday morning.
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