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I think I broke it. U-Joint

Author Topic: I think I broke it. U-Joint  (Read 14254 times)

Offline jaysenodell

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I think I broke it. U-Joint
« on: August 19, 2013, 07:26:12 AM »
Preface: I'm not a "car guy" so I may have some terms wrong. I'm still learning. Sorry.

After a but of fun yesterday I noticed a "clanking" from the front driver side wheel. I thought it was just mud/gravel in the suspension as it seemed linked to bumps. while pretending to clean up I noticed the front driver side U joint housing had a ring with no mud on it. Washing it off showed that the scoring was actually into the metal. the scoring appears to be created by the lower grease fitting for the steering pivot. I figure there are 2 causes:
1. I bent the C shaped end of the axel that holds the wheel on.
2. The U joint or axle bearing has given up the ghost.

Other than "take it to the shop" what should I do to diagnose this a bit better?
Mid Life Crisis in the making -- '02 TJ i4 manual, Aussie Locker magic pulling from the front

Offline Wingman

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Re: I think I broke it. U-Joint
« Reply #1 on: August 19, 2013, 08:20:57 AM »
Take a pic and post or link to it on here.  Sure sounds like a u-joint vacated a cap.  Open up the wallet...  ;D

Offline jaysenodell

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Re: I think I broke it. U-Joint
« Reply #2 on: August 19, 2013, 08:47:12 AM »
I'll get a pic in a few minutes. Not sure why i didn't think about that. Obviously it's because I'm an idiot.

You make it sound like I should start crying. Do I need to buy some flower on my way home?

Here's the spot that is hitting...

« Last Edit: August 19, 2013, 09:13:45 AM by jaysenodell »
Mid Life Crisis in the making -- '02 TJ i4 manual, Aussie Locker magic pulling from the front

Offline jaysenodell

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Re: I think I broke it. U-Joint
« Reply #3 on: August 19, 2013, 09:18:37 AM »
And here's the evidence that it is hitting (vertical line is on all the yokes).

Mid Life Crisis in the making -- '02 TJ i4 manual, Aussie Locker magic pulling from the front

Offline Wingman

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Re: I think I broke it. U-Joint
« Reply #4 on: August 19, 2013, 09:24:52 AM »
Hmmm.  That's odd to have the outer shaft rub like that.  The outer shaft should be good and tight inside the unit bearing and not allow movement that would cause contact like that.  My guess would be the unit bearing.

While it's apart, you might as well replace the u-joint with the most heavy duty unit you can get.

I recommend at least 6 roses... :P

Offline MrMindless

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Re: I think I broke it. U-Joint
« Reply #5 on: August 19, 2013, 09:25:33 AM »
First here's a little parts names reference.

In words:
The u-joint connects the inner and outer axle shafts at their "ears". It has (4) caps and a cross.
The knuckle steers; it swivels on an upper and lower ball joint that connect it to the inner C.
The tie rod connects the two knuckles together, the drag link connects that to the steering box. Tie Rod Ends (TREs) are used at all ends. There's also an adjusting sleeve on each.
Mounted to the outside of the knuckle is a Unit Bearing - it does the spinning.
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Offline MrMindless

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Re: I think I broke it. U-Joint
« Reply #6 on: August 19, 2013, 09:29:07 AM »
as far as diagnosis Mark is spot on - the outer shaft shouldn't be able to move in relation to the ball joints.

I'm not remembering there being enough clearence for a greaze zerk in the dana 30 lower ball joint, though. doesn't that need to get swapped for a plug after assembly and lube?

diagnosis of your unit bearing would involve jacking up the axle tube and seeing if the wheel and tire moves around in any way that it shouldn't.
Michael Maskalans
#571 Last Minute Motorsports
High Miler: 07.5 Ram 6.7 6sp 4x2, ARB, 19.5s
2003 R'Audi Allroad 6sp
Road Block: 98 Dakota 203/205 triple stick, 42" SXs
Dumpbus: 97 Ram 24v P-pumped, RoadRanger 13sp
'87 AMC Eagle Wagon

Offline smichaelR22

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Re: I think I broke it. U-Joint
« Reply #7 on: August 19, 2013, 09:56:11 AM »
check unit bearing nut is tight.  If there is a grease fitting on the top of the lower ball joints, there shouldnt be- no room, should be greased and replaced with a plug.

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Offline jaysenodell

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Re: I think I broke it. U-Joint
« Reply #8 on: August 19, 2013, 11:14:27 AM »
On the one hand I guess I'm glad that this is a bit more complex. I felt like a bit of an idiot. On the other hand I'm stumped as to why this just showed up after Whispering pines.

I clearly in over my head so off to the local shop it goes.

Just a thought... is it possible the plug is loose and what I think is a grease fitting is just the plug?
Mid Life Crisis in the making -- '02 TJ i4 manual, Aussie Locker magic pulling from the front

Offline Wingman

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Re: I think I broke it. U-Joint
« Reply #9 on: August 19, 2013, 11:24:05 AM »
If it is the grease fitting/plug, it will be self-correcting (break or grind off) and not harmful in the short-term.

Offline jaysenodell

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Re: I think I broke it. U-Joint
« Reply #10 on: August 19, 2013, 11:29:28 AM »
So the dilemma is let it be and see what gives up first or take it to the shop.

Or I could use the 1/4 brain I have and try to push the cap down. Looks like lunch break repair.
Mid Life Crisis in the making -- '02 TJ i4 manual, Aussie Locker magic pulling from the front

Offline jaysenodell

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Re: I think I broke it. U-Joint
« Reply #11 on: August 19, 2013, 11:53:03 AM »
Repair fail. More like "shatter cheap screwdriver win!"

Anyway, if the cap is press fit and about 3/8" in diameter, I think it is the cap. After removing some residue, the contact point is a 3/8" smooth sided cylinder with a flat top. It is wedged in there due to the smacking of the inner/outer ears. I tried to push it back to the right angle and press it down with a flat head screw driver but managed to do nothing more than create a need to go buy a new screwdriver.

I'll take it to the shop and have him check it out.

Thanks everyone.
Mid Life Crisis in the making -- '02 TJ i4 manual, Aussie Locker magic pulling from the front

Offline Wingman

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Re: I think I broke it. U-Joint
« Reply #12 on: August 19, 2013, 12:08:11 PM »
Sounds a lot like the grease fitting.  Have someone verify.  If it is, it'll be fine...

Offline jaysenodell

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Re: I think I broke it. U-Joint
« Reply #13 on: August 19, 2013, 12:30:57 PM »
Mechanic meeting at 5PM. I'll let you know how it goes.
Mid Life Crisis in the making -- '02 TJ i4 manual, Aussie Locker magic pulling from the front

Offline xjh3

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Re: I think I broke it. U-Joint
« Reply #14 on: August 19, 2013, 02:17:09 PM »
I'm going to agree with Smike on checking the 36mm nut on the outside of the unit bearing. If this wasn't a problem until after WP (read: lots of wheel speed) I'd say its possible a slightly loose nut became more loose and allowed the shaft to wobble and hit something it didn't before. In this case, sounds like that something is a zerk fitting.

There should be a castellated cover over the nut with a cotter pin through it. That's very easy to check for, and if missing... I'd highly suspect the nut is loose.
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