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PKFIRE
06-01-2009, 04:34 PM
I have a 03 Cobra. On the passanger side rear the car pops during bumps and backing out of driveway. I replaced the smaller 12mm IRS mount bolts to 14mm and that didn't solve the problem. The last car I had that made this sound ended up being a broken shock. I'm considering swapping left and right shocks to see if that is the problem. I wonder if you guys can give me any ideas on what to look out for.
Bluecrew07
06-01-2009, 04:43 PM
That was the problem for me. my gt used to do that and i replaced the shockes with Tokico blues and fixed the problem
facemelter71
06-01-2009, 05:31 PM
When I worked for ford,I had a brand new (had 2 miles on it) 03 cobra had a similar noise that ended up being a really fubar'ed rear wheel bearing.
You could plainly see the bearing being bad from just jacking the car up and tryin to wobble the tire.
PKFIRE
06-01-2009, 05:52 PM
When I worked for ford,I had a brand new (had 2 miles on it) 03 cobra had a similar noise that ended up being a really fubar'ed rear wheel bearing.
You could plainly see the bearing being bad from just jacking the car up and tryin to wobble the tire.

I've had bad wheel bearings before. I'm not hearing any bearing noises and the car tracks down the road perfect. The wheels do not have any play in them. I'll have to find someone willing to stick their head in the truck and listen,lol. It's frustrating trying to find noises like these by yourself.

The only two things I can think of now is sway bar and something wrong with shocks but I could be wrong also.
mustang8998
06-01-2009, 10:49 PM
Loose nut, behind the wheel?
Gearhead
06-02-2009, 05:40 PM
This might sound dumb, but what about the rubber trunk lid bumpers ??

They might be gripping the trunk lid, but when you go over a bump or back out of a driveway the body twists ever so slightly and they release or move slightly making a popping sound ??
PKFIRE
06-03-2009, 04:43 PM
The neighbors probably think I'm crazy backing into the driveway again and again to make the popping noise. There is a TSB on the rear popping on IRS cobras and it seems as though Ford ask you to over tighten each bolt. I've checked a few fasteners and they were in tolerance. I've already had this TSB done by Ford a couple of years ago. I'll try the Sway Bars this weekend. If I can remove them without taken the IRS out maybe I'll get new poly bushings to replace the rubber ones. I don't understand why Ford did that since the Front sway bar looks like it has poly bushings.

I'll check the trunk also. Really never thought about the trunk making any sounds but at this point I'll try anything to make the noise quit.
Gearhead
06-03-2009, 05:13 PM
The neighbors probably think I'm crazy backing into the driveway again and again to make the popping noise. There is a TSB on the rear popping on IRS cobras and it seems as though Ford ask you to over tighten each bolt. I've checked a few fasteners and they were in tolerance. I've already had this TSB done by Ford a couple of years ago. I'll try the Sway Bars this weekend. If I can remove them without taken the IRS out maybe I'll get new poly bushings to replace the rubber ones. I don't understand why Ford did that since the Front sway bar looks like it has poly bushings.

I'll check the trunk also. Really never thought about the trunk making any sounds but at this point I'll try anything to make the noise quit.

Let us know what you find out. Mine does it every now and then also.
PKFIRE
06-06-2009, 03:31 PM
This was a fairly weird find. I put the car on jack stands and took off both wheels. I placed a jack under the passanger rear A-arm. Since the pop happens when the springs load and unload. I was able to recreate the sound by jacking up under the spring. This pop sound resonated in the trunk. I thought it was the upper shock mount. So I removed the shock. Then I compressed the spring again. Noise was still present. Anyway after checking different spots I had a second person jack the car up while I was in the trunk.

In the photo below is spot a welded sheet of metal that under this load was deflecting and causing the popping sounds. I just bent it a bit and the noise went away.

http://img81.imageshack.us/img81/1203/dsc01622l.jpg (http://img81.imageshack.us/my.php?image=dsc01622l.jpg)
http://img81.imageshack.us/img81/7811/dsc01622bl.jpg (http://img81.imageshack.us/my.php?image=dsc01622bl.jpg)