How to Replace Ball Joints on a Jeep Wrangler JK

Chris

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Just like your own joints, the ball joints on your Jeep wear out over time. Fortunately, these joints can be replaced with new ones to freshen up that front end. It's not a very difficult process to change them out, all you need is some time and a bit of patience to complete.

If you're looking to never have to do this job ever again, there is a company called Teraflex that makes a heavy duty ball joint replacement for these Jeeps and claims they will last the lifetime of the vehicle. They are also a good choice if you are running over-sized tires on your Jeep that tend to wear out the stock replacement ones prematurely.

Whether you decide to go with the Teraflex ball joints or just to replace them with the stock style, the process of doing so is the same.

When doing a ball joint replacement, it's always a good idea to do both sides of the vehicle, as well as both the upper and lower joints because this will ensure that they wear evenly and rack up the same amount of miles.

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Materials Needed
  • Ratchet
  • 21mm socket
  • 13mm (12-point) socket
  • 5mm Allen wrench or socket
  • 15/16" socket
  • 7/8" socket
  • Breaker bar
  • Flat head screwdriver
  • Diagonal cutting pliers
  • Mallet
  • Ball joint press
  • Penetrating oil
  • Suspension grease
  • Jack and jack stands or lift
Before beginning, you will need to make sure you can acquire a ball joint press. You don't need to purchase one, especially if this isn't a job you do often. Most major auto parts stores will rent you one.

Step 1 – Remove front wheels
Seeing as how the ball joints are part of the front suspension, go ahead and remove the front wheels only. Of course, before doing this, you will need to raise the front of the vehicle off the ground using either a jack and jack stands or a lift if you are lucky enough to have access to one.

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Figure 1. Remove front wheels.

Step 2 – Install lug nut over wheel stud
Next you will want to take one of the lug nuts that you removed from the wheels and install it over one of the wheel studs. This will hold the brake rotor in place so that it does not fall off when you remove the brake caliper in one of the following steps.

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Figure 2. Install lug nut over wheel stud.

Step 3 – Remove ABS wiring harness from brackets
The ABS wiring harness is held securely to the front suspension by two brackets. They are essentially secured to the brackets by being pressed in, so you should only need your hands to pull them out of the brackets.


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Figure 3. Upper wiring harness bracket.


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Figure 4. Lower wiring harness bracket.

Step 4 – Remove 21mm caliper bracket bolts
The brake caliper assembly must be removed to complete this job. You can remove the brake caliper and brake caliper bracket as one piece by removing the (2) 21mm bolts that attach the brake caliper bracket to the steering knuckle.

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Figure 5. Remove caliper bracket bolts.

Step 5 – Support brake caliper assembly out of the way
Once you have removed the two brake caliper bracket bolts, you will want to move it out of the way and support it so that the assembly isn't hanging by the brake line. A good way to do this is to take a zip tie and run it through one of the bolt holes in the bracket and then zip tie it to the coil spring.

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Figure 6. Zip ties holding the caliper up by the spring.

Step 6 – Remove brake rotor
Now that the brake caliper is removed and out of the way, you will want to then remove the brake rotor. Loosen and remove the lug nut that you installed earlier to keep the rotor from falling off when you removed the brake caliper assembly. After you have removed the lug nut, the rotor should just slide off.

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Figure 7. Rotor removed.

Step 7 – Remove 21mm tie rod nut and tie rod
Next step will be to remove the tie rod. The tie rod is held into the steering knuckle by a 21mm nut. Loosen the nut until there are a few threads left, but don't remove it yet. Then you can take a mallet and tap the nut, which will help pop the tie rod out of the steering knuckle. Once the tie rod has fallen down, you can then remove the nut completely and swing the tie rod out of the way.

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Figure 8. Tie rod end nut loosened.

Step 8 – Spray uni-bearing bolts with penetrating oil
After the tie rod has been removed, the next thing you will have to remove will be the uni-bearing and axle assembly. The uni-bearing is secured to the steering knuckle, which is what holds the axle in place. If you locate the (3) 13mm bolts that secure the bearing to the steering knuckle and look at the back side where the bolts thread into the steering knuckle, you will see that there are some exposed threads. Spray these bolts with some penetrating oil before attempting to loosen the bolts. This will make it much easier to remove the bolts, especially if you live in a wet climate area where these bolts tend to get very corroded.

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Figure 9. Uni-bearing threads covered in penetrant.

Step 9 – Remove (3) 13mm uni-bearing bolts
Now that you have sprayed the threads with penetrating oil and let it sit for a few minutes, you can loosen and remove the (3) 13mm bolts. You might need a breaker bar to break the torque on the bolts first before removing them all the way with a ratchet.

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Figure 10. Uni-bearing bolts visible.

Step 10 – Remove uni-bearing, axle shaft and wheel speed sensor
Once you have removed the bolts, then you will remove the uni-bearing and the axle shaft as one whole assembly. Some times you will need to thread the bolts back in and tap them with a mallet in order to get the uni-bearing to slide out of the steering knuckle. As soon as it has moved out about a half inch or so, stop and remove the wheel speed sensor and bolt before removing it completely. Also, after removing the axle assembly, make sure that the nylon spacer is on the end of it and did not get wedged in the axle tube while removing it.

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Figure 11. Wheel speed sensor bolt.


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Figure 12. Removing axle shaft.

Step 11 – Remove upper and lower ball joint cotter pins
Next you will begin the process of removing the steering knuckle. To start off, remove the cotter pins in the upper and lower ball joints.

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Figure 13. Remove lower ball joint cotter pin.


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Figure 14. Remove upper ball joint cotter pin.

Step 12 – Remove lower and upper ball joints
After removing the cotter pins, you can remove the nuts that hold the ball joint studs into the steering knuckle. The lower ball joint nut is 15/16" and the upper ball joint nut is 7/8".

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Figure 15. Lower nut.


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Figure 16. Upper nut.

Step 13 – Knock steering knuckle loose from ball joints
Now that the ball joint nuts have been removed, you can take your mallet and tap the steering knuckle to free it from the ball joints. You might want to thread the nuts for the ball joints on a few threads to keep the steering knuckle from falling when it frees itself from the ball joints. After you see the steering knuckle drop down, you can then remove it and set it out of the way.

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Figure 17. Tapping ball joints free.

Step 14 – Remove ball joints
At this point everything has been removed to gain access to the ball joints and you can now begin to remove them. This is where you will need the ball joint press. A lot of these special tools are made by various different manufacturers. All of them are slightly different, so you will want to read and understand the instructions for the one you are using to make sure that you are using it correctly for this application.

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Figure 18. Press out upper ball joint.


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Figure 19. Pressing out lower joint.

Step 15 – Clean ball joint seat to prepare for new ball joint
The seat where the ball joint sits in the axle housing can become marred by the process of removing the old ball joint. You will want to clean the seat to prepare it for the new ball joint. This will make sure that the installation of the new ball joint is smooth and allow the new ball joint to grip the axle housing.

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Figure 20. Cleaning out ball joint seats.

Step 16 – Apply grease on new upper ball joint and seat
Before installing the upper ball joint, go ahead and apply some grease to the part of the ball joint that contacts the axle housing and the seat where the new upper ball joint will press into. This will aid in the smooth installation of the upper ball joint.

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Figure 21. Greasing ball joints.


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Figure 22. Greasing ball joint seat.

Step 17 – Press in upper ball joint
Using the ball joint press again, go ahead and press the new upper ball joint into the axle housing. There is a rubber boot that is part of the ball joint. You will want to press the new ball joint in with the rubber boot removed to ensure you don't damage it. Then once you have the ball joint completely pressed in, you can install the rubber boot in place onto the ball joint.

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Figure 23. Pressing in new upper ball joint.

Step 18 – Install lower ball joint
The lower ball joint requires a few more steps than the upper ball joint, as the lower one has some indexing marks that need to be lined up with the axle housing.

Install the set screws into the ball joint that are provided with the kit.

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Figure 24. Installing set screws.

Locate the indexing marks in the new ball joint. They are two small indentations on the outside housing the ball joint. Also, locate the indexing marks on the axle housing and mark them. They should be parallel with the frame of the vehicle.
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Figure 25. Index the ball joint to ensure it's installed correctly.


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Figure 26. Index marks lined up.

Grease the outside of the ball joint and the seat where it sits in the axle housing.


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Figure 27. Greasing the joint.


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Figure 28. Greasing the seat.

Press the new lower ball joint into the axle housing.

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Figure 29. Lower ball joint pressed in.

Install the rubber boot. Also, the lower ball joint has a boot spring, so make sure to install that.

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Figure 30. Ball joint circlip installed.

Step 19 – Reinstall removed components
At this point the new ball joints should be completely installed, and you can finish the job up by installing all the components that you had previously removed in the reverse order of removal.
  • Install the steering knuckle, the 15/16" nut on lower ball joint and 7/8" nut on upper ball joint.
  • Install the ball joint cotter pins.
  • Slide the axle assembly as well as uni-bearing back into axle housing and steering knuckle. Before tightening bolts completely, make sure to also install the wheel speed sensor back into place.
  • Install the tie rod and tie rod nut back into steering knuckle.
  • Install brake rotor and hold in place with lug nut.
  • Install brake caliper assembly and tighten brake caliper bracket bolts.
  • Place ABS wiring harness back into upper and lower brackets.
  • Remove the lug nut holding brake caliper and install wheel.
After installing new ball joints, you will want to go ahead and make sure to get the alignment of the vehicle checked and adjusted if necessary.

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