Are you sure it's from the back end?

I've known of gas tanks that suck in a bit during use and make a THUNK
when they return to shape shortly after shutdown.  This is usually
caused by a restricted vacuum canister.

Mike
Houlton, Maine

Bob O'Brien wrote:
> Hi Westy owners,
>
> I have a problem that perplexes me. After I park my van and turn off
> the ignition, often about a minute later or so, there will be a
> single "clunk" from somewhere in the back end. It doesn't seem to
> affect the driving as far as I can tell.
>
> Any ideas? Thanks.
>
> Bob O'Brien
> '85 Westy named "Goldie"
>