Shake diagnostic

Futbalfantic

Well-Known Member
Joined
Aug 5, 2006
Location
Charlotte
Vehicle 2010 Jeep Wrangler with 4”(?) lift and 35” tires.

Customer complaint. New front end shake. Starts 30 mins after driving and last approx 15 mins.

What diagnostics do you want to do and what are your thought.

Done so far. Jacked up with visual inspection. Nothing found. Ball joints, TRE, bearings feel tight.

Edit for additional information.

Jeep is parked near the water on the coast.
 
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rotate and balance the tires. no change? check alignment and all bushings again.
 
So my thoughts on this: The jeep lives on the coast, pretty close to the water. It sits for 7+ days at a time. Unknown type of rotors and pads but I am going to assume semi metallic. Rust builds up. The rust heats up while driving causing a lump. Shake ensues. Rust spot worn down. Shake goes away.
 
I've seen fix-a-flat cause some weird vibration as it slings around
 
Futbalfantic said:
But warped rotor would be constant right?
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Yeah, you would think so. Unless a caliper is dragging a little bit and causing enough heat after driving for a while to cause it to deflect just enough to feel. Just throwing out ideas. My wife’s 4-Runner had a rear caliper get a little sticky on the slide pins and it kinda acted the same. You could drive it until the vibration starts then check each wheel for excessive heat.
 
Hokie_YJ said:
Yeah, you would think so. Unless a caliper is dragging a little bit and causing enough heat after driving for a while to cause it to deflect just enough to feel. Just throwing out ideas. My wife’s 4-Runner had a rear caliper get a little sticky on the slide pins and it kinda acted the same. You could drive it until the vibration starts then check each wheel for excessive heat.
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But once it happened it wouldn’t resolve. This shake resolves after driving it for some time.
 
Soft brake line lining is collapsing. JK's are famous for it. Eventually it opens up enough to release the rotor and it won't always do it.

Had the same thing on my 30 year old motor home. It didn't do it all the time which made it hard to troubleshoot.
 
cranbiz said:
Soft brake line lining is collapsing. JK's are famous for it. Eventually it opens up enough to release the rotor and it won't always do it.

Had the same thing on my 30 year old motor home. It didn't do it all the time which made it hard to troubleshoot.
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Any way to confirm that?
 
Futbalfantic said:
Any way to confirm that?
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Not really. In general, if they are rubber lines, I would replace them.
rodney eppes said:
The Factory lines have probably been replaced by longer stainless braded lines, whenever the 4" lift was added. Might still be worth checking.
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You are probably right Rodney, however depending on the lift's manufacturer, they could still be rubber.
 
@Futbalfantic, have you test driven this Jeep and confirmed the symptoms are as the owner says? Or are you going by their word?

I ask because years ago my Granddad had someone bring their car and talked about how they had a flat spot on their tires or something wrong with their brakes. The car would thump thump thump down the road at higher speeds. long story short, Florida Interstates used to be concrete pads and my granddad had to tell the customer, You're an idiot.

The customer isn't driving the same route over and over and it the issue happens at the same time each time is it? :D
 
It’s my step-daughters car at college. i have test driven it and it drives like a jeep to me, a little squirrely when you brake hard but nothing terrible. And I don’t think it’s a road problem. She did have a jeep as her first car so should be used to it.

She goes to school in Charleston and can only drive it once a week if that. So my theory is semi-metallic break pads sitting for a week developing rust with the salt air. Drives it for a few mins to heat the rotors. Then the shakes develops until it’s worn off.
 
I'd closely inspect the track bar bushings and the mounting holes in the frame and axle end. The holes are known to wallow out and the bushings are junk. That would explain the wobble as well as the pull to one side.
The "does it after xxx minutes" aspect? Simple, the bushing(s) are marginally worn and driving accelerates the issue.
It's always the track bar. Even when it's not, it turns out to be the track bar.
 
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Jody Treadway said:
I'd closely inspect the track bar bushings and the mounting holes in the frame and axle end. The holes are known to wallow out and the bushings are junk. That would explain the wobble as well as the pull to one side.
The "does it after xxx minutes" aspect? Simple, the bushing(s) are marginally worn and driving accelerates the issue.
It's always the track bar. Even when it's not, it turns out to be the track bar.
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How do I go about confirming it? I tried to find movement in the front end weeks ago and couldn’t get anything to move.
 
Futbalfantic said:
How do I go about confirming it? I tried to find movement in the front end weeks ago and couldn’t get anything to move.
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Easy to check buddy.
Engine off, have someone wiggle the steering wheel back and forth rapidly from 10-2. Observe the trackbar for ANY movement. When I say ANY, I mean ANY movement.
The bushings are a known issue on JKs as are the mounts on the frame and axle side. They can wear over time and the holes are larger than the bolt diameter.
 
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