trizzbizzle

so i noticed a weird wobble from my front left wheel yesterday. i pulled off the wheel, calliper, and rotor to see if they were okay, they were. when i turn the hub, as it makes one full rotation, the hub oscillates slightly left to right, moving the steering slightly left to right with each rotation. any ideas as to what the issue might be? i'm hoping its not in the axle...any info would be greatly appreciated, i just replaced my entire clutch hydro system, now this! thanks in advance!

BlueXJ

Does the unit bearing seem to be fine or is the oscillation elsewhere?

trizzbizzle

yeah, the bearing seems fine. it seems like its off angle somewhere behind the hub. when i turn the hub, during the rotation the whole hub oscillates to the right, then back to the left, its only oscillating about a quarter inch but its also got a grabbing going on in the hub when it rotates out of center. its not too noticable going straight, but when i turn the wobbling is really bad, causing the steering wheel to pull back and forth. it feels similar to when making a tight turn in 4 wheel drive, but a lot more pronounced.

BlueXJ

Could it be a bad axle u-joint or a bent axle shaft?

Blackburn

Sounds like a bad unit bearing but I have seen the three retaining bolts work loose. The wobble and tight spot seems more like a bad bearing though

Blackburn

Thought about that Blue but wouldn't the bearing have to be bad in order to transmit any wobble through it? The bearing should have no play at all or it's junk.

BlueXJ

The bent axle is what has now messed up the unit bearing. If that is the problem. Can't see it from here so IDK.

Blackburn

I've seen a pile of broken 30 shafts never saw one bend

BlueXJ

Had one that was bent in my spares but don't know how it happened.

muddeprived

When you are turning, the steering wheel is jerking back and forth on it's own right? if yes, u-joints

Sounds like u-joint. Sometimes the u-joint would dry up and seize. When you turn the hub, the siezed u-joint will not allow the joint to bend and cause the knuckle/steering wheel to turn with it, hence teh steering wheel jerking back and forth on turns. I have this problem all the time because i do alot of mudding and the mud dries up the joints causing the wobble on turns that you have. Take off the unit bearing (3 bolts in the back and one large 36mm nut in front) and pull out the shaft. See if you can bend it at the joint in all directions. If it won't bend, then u-joint is shot.

trizzbizzle

thanks for your advice guys!

muddeprived, sounds like you're right on the money. i believe it probably is a seized u-joint by your description. last time i went mudding my clutch master cylinder crapped out on me so i got it in my driveway and there it sat, mud and all for over a month as i was out of town and could'nt get to it. its probably worth mentioning that my driveway is a little jacked up so the jeep sat unlevel that whole time. i'm guessing perhaps that might have added to the joint seizing.

after my first inspection, i put the caliper, rotor, and wheel back on and immediately noticed that the wheel was'nt binding nearly as bad, so i must have freed it up a little bit just messing with it. it still has some wobble to it though. any recommendations on the best way to unseize the u-joint? i really don't think its shot as i never had any problems before i parked it for a month. thanks again for everyone's input, this site rulz!

BlueXJ

U-joints are cheap so replace it and get one that you can grease. Fill it with grease before each wheeling trip. The grease filled cup keeps out water/mud contamination. Re-grease it after a wheeling trip to flush out any contamination that may have entered. The joints should last a long time with this type of care. JMHO.

muddeprived

Parking it on uneven surfaces for long periods of time won't harm or damage the u-joints. They are a normal wear-n-tear part that has to be replaced every couple years, depending on how the jeep is used. U-joints have caps on each end that contain needle bearings and grease. The grease keeps the needle bearings spinning as the cap rotates. After a couple years or a bunch of mudding, the grease slowly wears down till the caps are dry. When they dry up, they either seize up or the bearings start to shatter and you'll have a wiggle in the joints. Seized joints don't wiggle, they prevent the cap from spinning which doesn't allow the joint to bend and this causes that steering jerking on turns.
I would normally go through u-joints every year, sometimes twice a year with all the muddin i do. Like Blue said above, they are cheap and easily replaced with a ball joint press, vice, or just a hammer and couple sockets. Sometimes they have been on the vehicle for many years and are very difficult to remove. I had to use a 10,000 lb press to press mine out. THey were rust-welded in the axle shafts and i busted nearly every u-joint cap just getting them off. Hopefully yours aren't that bad. If you do not have a way of removing/installing the joints and need to go to a shop, save yourself some $$ and take the axle shaft to them, not the entire jeep. Shops charge an arm and leg just to get access to axle shafts. Ask me how i know.

But first, let's see if it's actually your u-joints Keep us updated.