Check the bolts that hold the shocks to the lower control arms. You said the the accumulators are new so that means you recently had the shocks out, right? When I replaced my rear shocks, I torqued the bolts to the spec in the WIS and the shocks still rattled when going over bumps. I finally got under there and tightened them 'till they felt "tight +- 10 ft/lb" and the clunking went away.

__________________
"It's not about how fast you can go, but how well you can go fast."

Bob in Richmond

'97 S320 (LWB), Ruby Red Metallic, 73k miles
'97 S420V, Smoke Silver Metallic, 155k miles