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Replacing XJ/TJ/ZJ ball joints

By Steve Leslie

***DISCLAIMER - Please note that this writeup is not intended to be used as a replacement for the factory defined repair proceedures. It reflects my experiences only and anyone using it for reference or as a guide, etc. does so at their own risk. You may link to this writeup, but you must obtain my permission to re-post it elsewhere.***

If you do a lot of hard wheeling on rough terrain where you flex the front suspension a lot or even if you've got a lot of miles on your Jeep, you might start having problems with ball joints. The ball joints are what hold the steering knuckle to the axle. They help hold caster angles while allowing the tires to turn right and left. Loose or worn ball joints can cause uneven tire wear. They can also cause vibrations that (over time) can and will do damage to other components of the steering and suspension.

Changing them is not beyond the scope of the DIY'er, but the job does require a ball joint press. Autozone's loaner tool program rents a generic ball joint press that is not the ideal version for 4x4's, but it will do the job. More on this later. Since the front ends of XJ's, TJ' s and ZJ's are virtually identical, the procedure is as well.

Tools required:
Floor jack
Jackstands (2)
6" C-clamp
Metric and Standard 3/8" and 1/2" sockets, ratchets and breaker bars
Needle nose pliers
Ball joint seperator (a.k.a. pickle fork)
Big F'n Hammer
Ball joint press
Torque wrench
Grease gun

Start by jacking up the front of the Jeep, placing it on jackstands (make sure to block the back wheels) and removing the tires. In this picture you can see the upper ball joint as well as the nut for the lower.

The first thing that needs to be done is to get the brake caliper and rotor out of the way so that the axle shafts can be removed. Pretty easy to do. See this writeup for detatiled procedures on removing the calliper and rotor. Next, it's time to remove the hub bearing and axleshaft. The pics show where the 3 retaining bolts are on the back of the knuckle. In the two pics below, the red circle indicates different views of the same bolt.

On my Jeep (and I suspect on most with unit bearings) the retaining bolts are 12 point heads and not 6 point. So you'll need to use a 12 point socket to remove them. It also helps to turn the knuckle to get better access to them. Once they are removed, the hub/axle shaft assembly can be removed. It might take a little "coaxing" to get the hub out of the knuckle...PB blaster will help make the job a little easier:

Now it's time to go after the ball joints themselves. The 2 pics below indicate the retaining nuts that hold the knuckle to the joint.

Start by removing the cotter pins. You can throw these away as most new ball joints will come with new nuts and pins, so confirm you actually have new ones. Once both the upper and lower nuts are removed, use the pickle fork and BFH at the upper joint to seperate the knuckle.

In most cases, this will cause the lower ball joint to separate as well (if, however, your uppers were as shot as one of mine was, it might not. In that case you'll have to use the fork on the lower joint as well in order to drop the knuckle).

Once the knuckle is out of the way it's time to remove the old ball joints. Now, in the past I have used the loaner tool from AutoZone. It does the job, but it is not perfect. The problem is that the loaner tool is for applications where everything is flush. On 4x4's, the mounts for the joints are on slight angles with respect to the joints themselves. In other words, you are trying to get leverage off an angled surface to press the joints in/out straight, making it a PITA. As I said, it works, but with 2 Jeeps being wheeled hard, it just made sense to buy the correct set of tools for the job.

As an added bonus, I can also buy the adapters for the main press that will fit our pickup truck, the Camaro and the two daily drivers, which contributed to my descision to purchase it:

The upper joint needs to be pressed up in order to remove it and down in order to install the new one. The lower needs to be pressed down to remove it and up to install it. Follow the instructions that come with the press you're using to choose the correct adapters for each operation. Also make sure you wear eye protection and keep your body in a safe position. You want to stay perpendicular to the lines of force that are being applied and be sure to keep good balance. There's a lot of pressure being applied to the tool and the joint will very rarely just slide out....most of the time it pops out with a bang (hence the need to maintain your balance). Basically, keep the tool in front of you like this so you can watch for any deflection/warping of the press and be out of harms way if something breaks:

Once the ball joints are out, follow the instructions/use the correct adapters to press in the new ones. At that point, you can reinstall the knuckle (make sure to put the grease boots on the joints before installing the knuckle), torque the nuts to spec and install the new cotter pins. The new joints I bought came with zerk fittings, but they were not installed. For my application, there is not enough clearance between the lower ball joint and the axle shaft for a zerk to fit and my old ball joints had a plug where a zerk woud fit. I simply installed the zerk, packed them up with grease and then removed the zerk and installed the plug. There was no problem with the zerk on the uppers.

Now it's just a simple matter of putting it all back together. Make sure you clean the splines on the axle shaft throughly and apply a film of grease before reinstalling and make sure you use care when inserting them so not to damage the inner seal in the diff. I was also installing new hub bearings since they were worn out as well, so I cleaned up the mating surfaces and used anti-seize to make it easier to get apart next time.

Make sure you torque the hub retaining bolts to spec.

At this point, it's as simple as reintalling the rotors, calipers (make sure to torque those bolts to spec) and the tires. You're done...take it for a test drive.

Rock On.

***DISCLAIMER - Please note that this writeup is not intended to be used as a replacement for the factory defined repair proceedures. It reflects my experiences only and anyone using it for reference or as a guide, etc. does so at their own risk. You may link to this writeup, but you must obtain my permission to re-post it elsewhere.***


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