that is the 'scientific' method..
bounce the suspension up and down a few strokes by pushing on the say, the
front bumper.
When you stop pushing ..
it should finish its stroke and stop immediately.

if there is any minor 'still cycling' ...
or if you know the shocks have many miles on them,
or see oil seepage out of the shocks..
they're due.

sounds like upper inner A-arm bushings squeaking to me.

Assuming a tire store mounted and balanced them ......You might check the
tire store's work.
There is no reason to assume they adjusted the tire pressures to vanagon
tire pressures specs.
or that they got the lug nuts tightened properly, and evenly, and not too
much ..
and they were careful with the hubcaps.
I don't even let any tire store touch my vans and cars. I bring them the
wheels only.
And even then..
I have to tell them I am willing to pay extra to have it done right,  and
carefully.

Scott
www.turbovans.com

----- Original Message -----
From: "Harry Hoffman" <hhoffman@IP-SOLUTIONS.NET>
To: <vanagon@GERRY.VANAGON.COM>
Sent: Friday, July 22, 2011 3:06 PM
Subject: How to determine when you need new shocks???

> Hi All,
>
> So, I just bought a new set of tires from Bus Depot. They are the
> Hankook 185r14 set. Cracked my bumper backing up to the "loading dock"
> :-(
>
> The van drives incredibly now!!! It's such a huge difference... but now
> when I'm driving over bumps and what not I feel like I'm back in college
> (or worse yet passing my parent's bedroom) and hearing a squeak, squeak,
> squeak when going over uneven surfaces.
>
> So, how do others determine it's time for new shocks? Do you push down
> on the bumpers and figure out how much (and how quickly) the van comes
> back up? Or is there a scientific method to computing this?
>
> Cheers,
> Harry