GT Performance Mods 2005+ Mustang GT Performance and Technical Information

Clunking Sound From Rear?

Old Jul 20, 2007 | 06:24 PM
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Question Clunking Sound From Rear?

I have a clunking sound when I go over expansion joints or railroad tracks straight on. It sounds like the spare tire not being fastened down, but it is. If I go over railroad tracks at an angle or expansion joints, no clunk!

Top mount of shocks? Upper control arm? I have checked the torque on the LCA's and the panhard bar and everything is right on.
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Old Jul 20, 2007 | 07:51 PM
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Did you cut the bumpstops when you installed the rear springs? I've yet to do mine, but that's what has been suggested to me.
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Old Jul 20, 2007 | 07:59 PM
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I don't think that would be an issue with a 1 inch drop in the rear.
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Old Jul 20, 2007 | 08:02 PM
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my spare was or at least seemed tight but was still making noise. I have removed it. Did you do a complete roush suspension? I did springs but didn't change my shocks and struts. I get the bang over bigger bumps
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Old Jul 20, 2007 | 08:02 PM
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Just in case, here's the thread I was referencing:

http://forums.bradbarnett.net/showth...light=bumpstop

Again, your noise could be a 1000 different things- just trying to help.
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Old Jul 20, 2007 | 08:04 PM
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Originally Posted by GRAYPNY
I don't think that would be an issue with a 1 inch drop in the rear.
I droped mine one inch and didn't hear the bang, but after I went with the 1.4 inch drop is when I picked up that bang over the bigger bumps
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Old Jul 20, 2007 | 08:07 PM
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Maybe I'll take the spare tire out and run it for afew days and see how it sounds. Of course as soon as I do that I'll get a flat. I can't remember, is the spare a donut or a full sized tire?

Glenn - I have the springs, struts and shocks. Not the sway bars.
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Old Jul 20, 2007 | 08:08 PM
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donut
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Old Jul 20, 2007 | 08:12 PM
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No thanks Tom. But call me in the morning when I have my coffee!
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Old Jul 20, 2007 | 08:15 PM
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Old Jul 21, 2007 | 05:45 PM
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lol
Please keep us informed.
shouldn't be a bang with all that you have done. By the way the spare and jack weigh 30 pounds. I'm not putting mine back in. If I get a flat I'll call some one to bring my spare to me LOL hope fully I'll be close to a drinking hole
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Old Jul 21, 2007 | 05:47 PM
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It may just be that the shocks are not up to the job of handling the stiffer Roush springs and the fact that you are hitting railroad track and major expansion joints straight on. When you hit those things at an angle the tire engages the gap progressively so the shock to the suspension is greatly softened or nil.

I assume you installed all your BMR stuff to factory spec's ... or checked that they are stiff tight?
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Old Jul 21, 2007 | 05:50 PM
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I have the entire Roush suspension except for the swaybars Paul.


BTW this clunk isn't something new, it's been around for awhile.
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Old Jul 21, 2007 | 07:00 PM
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I think sway bars would be one of the last things I would do. I base that on what I have read and learned her. firming things up else where is what I am going for first. With What you have Rich, I feel you shouldn't be hearing any thing abnormaly. Is there ay way you could go take a roush stang for a test drive at a dealership??
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Old Jul 21, 2007 | 07:02 PM
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If your exhaust tips are too close to your bumper they will make that sound when going over bumps.
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Old Jul 21, 2007 | 08:01 PM
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Originally Posted by GRAYPNY
I have the entire Roush suspension except for the swaybars Paul.


BTW this clunk isn't something new, it's been around for awhile.
Time to do a close inspection underneath the car ... exhaust tips to the front connection on the LCA. Everthing tight underneath (i mean everything!)? Any clearances look tight. Any witness marks where things have been rubbing or hitting. Grab the exhaust system and push pull in all directions ... anything hitting? If noting then its a performance limitation of the shock spring package.

You seem handy with a camera. Have someone take a movie of the car as it goes over the rr tracks. Aim the camera right where the wheels goes over the track. Don't try to pan. Then go back and look at the wheel action in slow motion or frame by frame. You will be surprised how much movement there is.
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Old Jul 21, 2007 | 08:50 PM
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Originally Posted by GRAYPNY
BTW this clunk isn't something new, it's been around for awhile.

Geez, that's the same thing I say about my wife......
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Old Jul 21, 2007 | 09:17 PM
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Originally Posted by NJ3
If your exhaust tips are too close to your bumper they will make that sound when going over bumps.

WORD! Mine does this. I've tried to adjust them better to no avail...
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Old Jul 22, 2007 | 12:23 PM
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Check the over axle pipe on the driver side and see if it is hitting on the Panhard Rod Upper Support.

Also double check all bolts to make sure things are tight enough. Remember the suspension bolts are torque to yield and if you did not replace them when you did all the suspension work it is possible they have loosened.


Richard
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Old Jul 22, 2007 | 12:29 PM
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Originally Posted by 06GT4RAD
Check the over axle pipe on the driver side and see if it is hitting on the Panhard Rod Upper Support.

Also double check all bolts to make sure things are tight enough. Remember the suspension bolts are torque to yield and if you did not replace them when you did all the suspension work it is possible they have loosened.


Richard
+1 Susupension bolts/nuts and others are 1 time use as stated by ford so they should be replaced with new parts. Dealer charged me 53 bucks for the P/H rod and brace H/W.
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