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  #1  
Old 07-09-2003, 03:45 AM
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Jeep Grand Cherokee Laredo, Shimmy Question -

Anyone have any experience with these?

I am trying to help a single mom next-door neighbor with her 1993 Jeep Grand Cherokee Laredo. It is an automatic with 4-wheel drive.

At about 40 MPH the front end starts to shimmy and it gets worse the faster she drives. It has about 147k on it. She's had it to several indies but they all don't have a clue. They keep telling her to get rid of it.

I looked briefly at the front end tonight and I did see a steering dampener. We discussed that it could easily be that part although it does look dry. I suppose testing it would be the same as with a MBZ and detach on side and see if it has any dampening left in it.

Any other ideas on this rig? It would be great if we could help her out and solve this.

Thanks in advance,

Haasman
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  #2  
Old 07-09-2003, 05:10 AM
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Ask her if the problem developed gradually or rather quickly or suddenly. Getting some accurate history on the problem could go a long way towards solving it.

Could be anything from worn out joints, bushings or other components to a wheel weight that's come off or a tire casing that's coming apart (look for any large "bubbles" in the sidewall or unusual tread wear patterns).

Check all the lug nuts and make sure they're all tight.

Check for badly worn wheel bearings.

Look for accumulated wear in the various suspension components.

If you have a way to get both the front wheels off the ground, grab them at 12 and 6 and then at 9 and 3 o'clock and just move them back and forth to see what kind of play you find, and where. Get the wheels abut 2-3 in. off the ground so you can get a crowbar under it and lift. If the wheel moves up and down, but one or both of the suspension arms don't, that could be part of the problem.

Let us know what you find. Might be useful sometime on one of our cars if it ends up being something rather generic.

Good luck.
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  #3  
Old 07-09-2003, 08:47 AM
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little known

but many times the cause of this problem is a "shifted" steel belt in a radial tire...we have the same vehicle with a mild shimmy..and are diagnosing it now.. done everthing else
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  #4  
Old 07-09-2003, 10:39 AM
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It's a VERY common problem, and could have many different causes, and solutions..

For you reading enjoyment.. I searched the Grand Cherokee forum for "shimmy", and got a kazillon hits..

They also call it "death wobble"

http://www.jeepsunlimited.com/forums/search.php?s=&action=showresults&searchid=261564&sortby=lastpost&sortorder=descending

This is a very busy, underpowered website, so you may have to wait until off peak hours to use their search function..

One of the most common problems is with front end alignment.. Set the toe to 0*.. You can do that in the driveway, with a tape measure, piece of string, etc.. That would be my first place to start..
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Last edited by jay3000; 07-09-2003 at 10:45 AM.
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  #5  
Old 07-09-2003, 11:16 AM
LarryBible
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You MUST understand that "shimmy" is not CAUSED by worn steering or suspension components or misalignment. These things will allow a vibration to be amplified and transmitted. The SOURCE of such vibrations begins with ROTATING parts, almost always wheels or tires.

I would give this a 99% chance of being caused by something wrong with wheel(s) or tire(s).

To begin with ensure that the wheels were DYNAMICALLY balanced meaning weights are used on the inboard AND outboard wheel lips. Second most common situation would be a broken belt or other tire flaw causing excessive road force variation (stiff spot.)

To verify wheel/tire integrity find a shop with a Hunter GSP9700 wheel balancing machine. This machine not only checks for wheel balance but also has a pressure wheel to search for stiff spots. To find such a shop go to: www.gsp9700.com There is a locator on that sight.

BTW, does this mean we now need to change the URL for this site to "www.DaimlerChryslerShop.com?"

Good luck,
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  #6  
Old 07-09-2003, 01:17 PM
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Thanks for the suggestions, I will check them all out.

Larry, no I don't think the site should be renamed- DaimlerChryslerShop.com .... just looking for expertise, such as yours to help a good person in need.

Haasman
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  #7  
Old 07-09-2003, 04:39 PM
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I actually own one of these beasts as well.

Front end problems are very common with this solid-axle holdout.

The steering dampener does absorb some 'bump-steer', but otherwise just masks any underlying problems with play in the steering. Larry made some good suggestions (as always).
Here are some more.

1) Make sure the steering box itself is tight. Look for excess play before the steering arm even reacts. Adjusts just like a 124, but in the reverse direction! Made a big difference in my case.
Check the steering box bolts and bracket as well. These are known for coming loose, or even cracking. Mine has been ok.

2) Check the Trackbar joint and bushings. Joint (frame end)has a grease fitting, so it will last *forever* if lubed and the boot is intact. Bushing end (axle) is a common wear item.

3) Steering linkages are an obvious potential source of trouble. They all have grease fittings, so they will last if greased.

4) Control Arms (4 of them) have bushings that can wear out. They last pretty long, but at 147k...

5) Wheel hub assembly pivots on what is essentially a fixed hinge(solid axle, so moves in just one plane) with a top pin, and a lower pin. The top pin has a grease fitting. These things are not generally the 'weak link', but that is a lot of years and miles.

6) Swaybar bushings wear out even faster than on an MB! Not really a "shimmy' issue, but does lead to general instability.

7) After carefully going through all of that other stuff, my biggest Death Wobble contributor was found to be a worn hub bearing. It had significant play, but made zero noise. These are pressed one-piece hubs (like on a typical fwd), which cannot be adjusted to set preload. These things are known to have a short lifespan. They are expensive, but easy to replace.

The whole front suspension is very primitive, but also relatively easy to service. No worries about camber settings! When all front-end components are in good shape, it handles better than one would imagine.
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  #8  
Old 07-09-2003, 04:46 PM
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csnow

Thank you for the specifics, very helpful. I will start going through the list. I called the local Jeep dealer and the friendly service advisor ranked the following as likely suspects:

-wheel balance
-steering dampener
-steering gearbox adjustment
-drive train members bent

Thanks again,

Haasman
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'91 300E-Went to Ex
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