Clank or clack coming from rear

[NSX-Men]

My NSX makes a clanking sound in the rear somewhere when I run over expansion joints or sharp bumps in the road. It’s loud and really annoying.
On smooth roads there is no sound even when I get on or off the throttle hard.
It is a 2000 and it has 134,000 miles on it.
I have checked -

• Wheel bearings. I even took the brake calipers off, put the wheel back on for leverage and could find no looseness or noise, everything was smooth.
• CV axles. With the car in the air and no load on them, the axles move smoothly in the CV sockets and there is no free play radially.
• Suspension bushings. All of the bushings look like new still and all of the bolts are tight.
• Shock absorbers. The shocks still work correctly, no looseness or bouncing, and no loose bolts or mountings.
• Parking brake cables. All of the tie downs for the cables appear to be in place and it doesn’t look like they could move and tap on something to cause the noise.

The only thing I can find is that the brake backing plates, when tapped with a rubber mallet, make a sound similar to what I am hearing when I am driving, but not as loud.
I am hoping that someone else has experienced this phenomenon and has figured out where the noise is coming from.

 

[BATMANs]

exhaust bushings?

 

[JD Cross]

This may not be good advice but I had a similar sound.
I put some oil on the lower suspension bushings and the rear swaybar bushings and the noise went away.

 

[neonshaun]

pretty sure im having the same issue.
I believe it's the retainer springs on the pads?

When I go over bumps and lightly old my e-brake, it doesn't clank.

 

[NSX-Men]

I FOUND THE CLANK!!!
Took the rear brakes apart again, I didn't look that closely the first time because it appeared that the previous owner had just replaced the rotors and pads. I made the mistake of assuming that the job had been done correctly. The noise was loudest on the left rear (it was incredibly loud and embarrassing), the springs that were supposed to keep the pads from rattling around were not doing their job, a little tweaking to the springs and the noise is GONE.
While I was in there I discovered that whoever installed the brakes did not align the boss on the back of the inner pads with the slot in the piston on both sides of the car so the pad was not fully contacting the rotor.
One other thing I did was to attach short pieces of split windshield washer tubing to the backing plates (they clipped on really tightly), even though the backing plates are in as-new condition and the bolts are tight, if you tap them with a plastic mallet they rattle loudly like symbols, now when you tap them they just make a dull quiet thunk.
Many thanks to neonshaun!

 

[JW]

Check out this link.

http://www.nsxprime.com/forum/showthread.php/169395-NSX-clunk-in-rear


91 NSX Red/Black
09 VW Jetta TDI White