advice on diagnosing a bad ball-joint?

I recently noticed some very loud road noise after I had my new BFG KM2s rotated for the first time since I purchased them back in December. I inspected the tires since they were much louder than before and I noticed two out of the four had some uneven wear. Being a former auto student I got out my big automotive text book (this thing has everything and its like 3 inches thick) and looked up the section on tires. It showed different various possible wear patterns which the closest one to mine was "cupping" which gave a few different possible reasons, one of which was wore out ball-joint. I know there are alot of other possible reasons that the tires are wearing unevenly and I will address those too especially alignment. But since I have never tried diagnosing a bad ball-joint before I thought I would get some advice from a fellow Jeeper. The book gave some ways but they were general automotive to cover all cars across the board. But I figured someone here could give me a sure fire way to do it on a Jeep. So any suggestions?

Jack the Jeep up so that the tires are a couple inches off the ground. Put a long lever, like a tire iron or jack handle, under a tire and lift up. If you feel play, then the ball joints are bad.

When I do this on my Jeep, I can actually see the upper bad joints moving back and forth. Sooo... it's time for me to replace them. These ones are about 4 years old.

Well I went out and tried that but with 33" BFG KM2s that are fairly new I didn't see much movement. But when I stuck my pry bar in between the lower part of the outter C and the yoke of the axle shaft and pushed upwards I definitely saw movement. Not a whole lot like some of the videos on youtube that I looked up but there was some movement and I heard a slight knock noise, faint but it was there. This was done on the passenger side and since I didn't know how much movement was allowed, if any, I checked the other side for reference. I figured the other side would have no movement and I would know the passenger side was bad or the driver side would have the same amount and tell me that either both sides are bad or they are fine and I need to look elsewhere. But the driver side had no movement at all, thought I think I need to replace the alxe shaft u-joint because that had some play in it. So I think I need to replace the ball-joints on the passenger side. How do I know if I should replace the upper or lower? Because they were both moving some.

Yeah... my right balljoint on the MJ failed that test when I put the axle in. I just plain didn't care :dunno:

Moves up and down about 1/16" to 1/8".

Replace both balljoints while you're in there, it isn't worth the trouble to have to go in again. Insert them in a specific order (forget which, think it through and it'll be clear) or you won't be able to put the second one in easily. Stick with the good brands - Dana Spicer, Moog, Timken if they do balljoints.

Wow all those are pretty expensive from what I have seen looking them up. Any body had luck with the more affordable local parts store? I have had good luck with some duralast parts from autozone like the water pump and a few other things. Or NAPA? They usually has pretty good stuff. I am a college student with no income living off of loans that are supposed to last the whole semester and trust me it isn't much so I have to budget and save accordingly to make it last. I bought new tires and the bad ball-joints are causing them to wear unevenly so I want to protect my investment and get the joints replaced as soon as possible. If I have to replace them in three or 4 years that is fine because I will be out of college by then and I will have a job to pay for the good stuff haha

Try alljeep.com. I got my WJ "super 30" balljoint kits (all 4 joints) for something like 90 dollars shipped there.

Also, try your local pull-a-part for new tires - they have a LOT generally and usually the prices are very reasonable, 10 to 20 dollars per tire.

kastein said:

Try alljeep.com. I got my WJ "super 30" balljoint kits (all 4 joints) for something like 90 dollars shipped there.

Also, try your local pull-a-part for new tires - they have a LOT generally and usually the prices are very reasonable, 10 to 20 dollars per tire.

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Wow that is a hell of a deal but I went to the site and the Dana 30 Super ball joint kit is only for 99 and newer which is a bit of a bummer and the regular ball joint kit is good for 85-06 which is a little confusing and its more expensive than the Dana 30 super kit. Oh well still a good deal. How they working out for you? Have you had them long? Do you have bigger tires on your Jeep? I'm running 33s so I have to make sure to get something that can handle off-road abuse with 33s.

Ben824 said:

Wow all those are pretty expensive from what I have seen looking them up. Any body had luck with the more affordable local parts store? I have had good luck with some duralast parts from autozone like the water pump and a few other things. Or NAPA? They usually has pretty good stuff. I am a college student with no income living off of loans that are supposed to last the whole semester and trust me it isn't much so I have to budget and save accordingly to make it last. I bought new tires and the bad ball-joints are causing them to wear unevenly so I want to protect my investment and get the joints replaced as soon as possible. If I have to replace them in three or 4 years that is fine because I will be out of college by then and I will have a job to pay for the good stuff haha

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One of the SoCalXJ.com guys managed a group buy on Timkins. All four for $60. Pretty much everybody out here jumped on that deal even if we didn't need them.

Ben824 said:

Wow that is a hell of a deal but I went to the site and the Dana 30 Super ball joint kit is only for 99 and newer which is a bit of a bummer and the regular ball joint kit is good for 85-06 which is a little confusing and its more expensive than the Dana 30 super kit. Oh well still a good deal. How they working out for you? Have you had them long? Do you have bigger tires on your Jeep? I'm running 33s so I have to make sure to get something that can handle off-road abuse with 33s.

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They're listed for 99 up because they are for the WJ knuckles - until 98, the XJ and ZJ shared the same exact balljoints. The super kit will NOT work for you unless you are upgrading to WJ brakes, knuckles, steering, etc.

I've had them for about a month now, haven't had time to install them on the axle they're going on - an hpd30 with 4.10s I have in my storage unit. I'm running 33s on the current rig with a stock axle and stock gearing, the new rig is getting the 4.10s, WJ brakes/steering/balljoints, and an 8.8 all at the same time. Right now I have nowhere to work on my jeeps though which makes things take longer than I want. I can't do anything in my apartment parking space and end up doing repairs and such in parking garages after-hours, so I can't do anything that takes longer than an hour or two and doesn't look like an emergency repair.

The thing that still confuses me is I have read up on many people doing the WJ knuckle conversion for the bigger brakes and none of them say to swap in WJ ball-joint which would me they are using the OEM joints that came on the XJ dana 30 which makes me still wonder why I couldn't use the super 30 ball-joints. I guess I am just missing something but it appears that there is no difference based on all of that.

You can get away with doing that for a while, but the taper on the lower one is different and over time it will wallow out the hole in the knuckle and ruin it. Going the other way will either do the same thing, or simply won't fit, I'm not sure which but I think the latter since the WJ lower balljoint taper is larger. The upper WJ and XJ (and TJ as well to further muddy the waters) balljoints are exactly the same, on the other hand.