Based on your description about dive under breaking, I would check if of the shock bolts may have come off or broken. A loose shack will tend to rattle. A broken shock bolt will definitely cause excessive dive. 

Try that first since that is relatively easy to check. I have Bilstein HD's in two of my Vanagons. If anything, they are quieter than the other brands. One brand is of such low quality that top mount got beat up enough to cause clunking up front. In that situation, there were no problems with dive.

BenT

Sent from my HD shocks 

On Nov 4, 2010, at 4:42 PM, Michael Hart <mjhart853@YAHOO.COM> wrote:

> Suspension seems to have gotten more noisy with time (complaints from son &
> spouse increasing...). Most noticeable at low speeds on rough roads - clunking
> and 'deep rattle' (don't really know how better to describe it). Noises seem to
> come from the back, but unsuccessful in locating (nothing obviously loose, hard
> to localise when driving). After refurbing the front heater flaps & seals, this
> will be the major source of noise (I have already installed Fatmat over the
> floors & in the walls/doors etc.)
> In addition, the front seems to dive more recently under heavy braking (perhaps
> 4 - 6 inches?) but I fitted new HD Bilsteins all round 4 years / 40k miles ago.
> Is it likely these are worn & source of the noise?
> 
> Seeking your expert advice.
> Mike
> '87 Westy 145k miles