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post #1 of 3 (permalink) Old 08-14-2010, 11:36 PM Thread Starter
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Th-lunk Sound from the Front End, Going Over Bumps

Hey guys, this thread is similar to this one - however my problem is just a lil bit different.

I have a 07 LS with about 40k miles. Right after I bought it, I noticed that when I go over decent sized bumps (speed bumps for example), the front end makes an obnoxious thud/clunk sound. The sound is most certainly coming from a part compressing and hitting another part but, I have no idea what part it could be. I've tried to reproduce it by bouncing the front end and taking the wheels off and pushing up on the suspension from the bottom but, I couldn't reproduce the exact sound.

My first thought was the strut mounts but after reading various threads and articles, it sounds like it should be the control arm bushing. Does anyone have any experience taking the suspension apart and checking the control arm bushing? I'd hate to buy the parts and tear everything apart only to find out that this bushing isn't the problem.
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post #2 of 3 (permalink) Old 08-15-2010, 01:48 PM
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Well, I don't know about checking the bushings (though if they're torn or slop around, you have an issue) - but taking apart the suspension isn't too bad (I just did that).

To remove the control arm, you just need to unbolt the pinch bolt/nut from the bottom of the spindle (knuckle), and separate the control arm from the knuckle, and then support the knuckle. Unbolt the control arm from the frame (one large vertical bolt at the rear and two 15mm bolts in the front - hard to miss). Should come right out.

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post #3 of 3 (permalink) Old 10-18-2010, 08:28 PM
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Be careful of the nut that is on the large vertical bolt .It is in a cage to keep it from spinning.Mine would not go back in. The nut is stripped.Both lower A Arm bushings were shot in mine.I replaced the links also. Then driving it about 10 miles, the engine shut down, the POWER STEERING light came on and after all the time and money I spent on parts, I parked it, It's a 2005,not paid for yet with 103,000 miles and ready for the bone yard and the last GM I ever buy after over 36 years of owning GM.
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