Ball joints are one of those common factory wear items that will need to be replaced on your Jeep, with the typical service interval of tens of thousands of miles when running the stock suspension and tires. However, factory ball joints won’t last nearly as long when they are subjected to the added weight and leverage that larger tires and wheels and the immense stress and loads of off-road driving place on the steering knuckles.
Lifted Wranglers running 35-inch-or-taller tires can expect the life of stock ball joints to be cut in half, maybe even less if there’s a lot of off-roading added to the driving mix. When ball joints near their end, one of the most common signs it’s time for replacement is a clunking sound coming from the front end that can also be felt through the floorboard. Other common signs of bad ball joints are vibration in the steering at speeds between 50 to 60 mph, steering wander, and sometimes “feathering” of the front tire tread or accelerated wear on the inner portion of the tread.
The quickest way to check if the ball joints are shot is by jacking the front tires about an inch off the ground and resting the housing on jackstands. Place a crowbar or two-by-four under each tire so you can lift the tire vertically. If the tire can be moved upward without moving the suspension, and/or a clunk is heard, it’s time to replace the ball joints.
Ball joint replacement can cost upwards of $500 at a repair center. Doing it yourself can shave several hundred dollars off the shop price. But plan on spending at least a half-day to likely a full day for the first-timer. It will also necessitate having a ball joint press, which can be rented from a number of parts stores, or purchased if you plan on doing this more than once. If you purchase a kit, a good investment is the OTC 8031 because it has the special adapters to accommodate the taper of the steering knuckle where the ball joints fit. You’ll also need basic handtools, including a torque wrench.
Ball joints are the anchor point for the front wheels, allowing them to rotate when the steering wheel is turned. They also carry the full weight of the front end and the forces generated by the tire/wheel assemblies hanging off the front axle.
It will also pay to upgrade from the Mopar/Jeep ball joints to a heavy-duty aftermarket kit like those offered by Synergy Manufacturing (Amazon.com; ASIN B00ISE9FJM). Synergy’s heavy-duty Jeep ball joints are a much stronger, greaseable metal-on-metal design than OE with bigger studs made from 4140 steel and protected with special silicone polyurethane boots. They are designed to take the weight of bigger tires and wheels.
That’s the route Dunks Performance was taking when we leaned in to watch the front-end specialist go about replacing the factory ball joints on an ’06 Wrangler LJ running a 4-inch lift and 35s. We hope the highlights we captured will help make it easier when it comes time to replace the ball joints on your Jeep.
Replacement began by working on one side at a time. We first removed the bolts that held the brake caliper in place.
To remove the brake caliper, we used a screwdriver to pry the pads away from the rotor. Then it slipped easily off the rotor.
Once we had the caliper off, the rotor slid easily off the unit bearing. This is a good time to inspect the rotor and have it turned or replaced if needed.
Pay attention to the way the splash guard’s notch is oriented for the steering knuckle because it goes back the same way during reassembly.
Three 1/2-inch bolts held the hub (unit bearing) to the steering knuckle. We used a 1/2-inch air gun to break them free, but DIYers may need to have a breaker bar because the nuts are torqued to 75 lb-ft on Dana 30s and 125 lb-ft on Dana 44s, like the one under the Wrangler LJ we were working on.
Once we had the retaining bolts removed, we could slide the axleshaft out of the housing. Support the axleshaft once the hub is clear of the knuckle to keep the splines from nicking the axle seal where the shaft enters the differential.
We loosened both the upper (22 mm) and lower ball joint nuts (28 mm), then used a hammer to give the steering knuckle a hard rap to pop it free from the tapered studs. Leaving the nuts on prevents the steering knuckle from falling off and potentially getting damaged.
We used Synergy Manufacturing’s heavy-duty ball joint kit (two upper/lower ball joints; P/N 4120) that has a greaseable, sintered metal-on-metal design, which is far more robust than the stock Jeep ball joints. The boots are made from silicone polyurethane, also a big step up from the factory ball joints.
A ball joint “press” is a critical tool in the R&R process. Our Jeep’s axle housing was on the bench for some gear work, but removing and replacing the ball joints can be easily done on the rig. The C-clamp–style press makes it easy to push the old ball joints out and the new ones in using either an air impact or ratchet. Ball joint press kits can be rented from a number of auto parts stores.
Our lifted LJ’s ball joints (right) had 60,000 miles on them and were beginning to “clunk.” We replaced them with Synergy heavy-duty versions (left) that have bigger studs and a meatier bearing design that will handle the bigger tires.
After we had the upper ball joint removed, we turned our attention to pressing out the lower one. Removing the upper first allows the tall screw of the press to extend up through the top of the axlehousing “C” that holds the steering knuckle.
When you get a ball joint press make sure it has the correct adapters for a Jeep. It’s very important to make sure the adapters, which have a slight taper, are placed so they provide a perfectly straight press because the axlehousing “C” ends are also tapered. Some press kits don’t have the proper adapters for this, making the installation more difficult.
Install the new upper ball joint in the same way as the lower one. Make sure it’s cleaned before installation, and that the “receiver” and “sleeve” of the press kit are aligned with the taper of the axle “C” for a straight push into place. Shoulder of the ball joint should fit tight against the “C” (no gap).
One trick Dunks Performance does in a Jeep ball joint R&R is to use a small deburring tool to grind a small notch where the grease zerk fits in the lower ball joint. The zerk is then easier to access for maintenance.
After the new Synergy ball joints are in place, the rest of the job is reinstalling the parts in the reverse order they were removed. Torque the upper ball joint’s castellated nut (22mm) to 75 lb-ft and the lower 28mm nut to 80 lb-ft. Jp Pro Tip: When reinstalling the axle, lay the shaft of a large screwdriver in the axletube to help support the axleshaft as the end splines slide into the differential. Supporting the weight of the shaft on the screwdriver helps keep the sharp splines from cutting the axle seal.
Installing Synergy’s heavy-duty ball joints are a great upgrade to do when lifting a Wrangler TJ/LJ to run taller tires. They improve the handling and are designed to withstand the greater forces such changes put on the front axle assembly.
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