Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP
Posting-Version: version B 2.10.1 exptools 1/6/84; site ihuxk.UUCP
Path: utzoo!watmath!clyde!cbosgd!cbdkc1!desoto!packard!edsel!bentley!hudson!ihnp1!ihnp4!ihuxk!rs55611
From: rs55611@ihuxk.UUCP (Robert E. Schleicher)
Newsgroups: net.consumers
Subject: Re: Re: cars in Europe
Message-ID: <817@ihuxk.UUCP>
Date: Mon, 3-Dec-84 18:40:51 EST
Article-I.D.: ihuxk.817
Posted: Mon Dec  3 18:40:51 1984
Date-Received: Tue, 4-Dec-84 19:45:55 EST
References: <910@druxj.UUCP>
Organization: AT&T Bell Labs, Naperville, IL
Lines: 32

I'm not sure that Citroens don't have any suspension with the engine off,
as this would imply to me that Citroens would sit on their tires when turned
off.  I think what is perhaps more likely is that the suspension is 
"frozen" at its most recent effective spring rate.  This by itself would
not be a problem for a drop test.  What may be the real problem is that 
the Citroen suspension should not have all four (or even perhaps two) wheels
off the ground for more than a second or so, as then the hydraulic suspension
would basically "blow itself out".

This is just supposition on my part, but is based on the behavior of the 
air suspension on my '71 Mercedes 300SEL 3.5.  This design uses a compressed
air system for the springs, with normal shock absorbers.  As in Citroens,
the suspension is self-leveling, with one sensor at the back, and one at 
each front wheel.  (similar to new Lincoln system).  There is a three position
switch under the dash.  Position 1 is for normal driving, position 2 "locks"
the suspension, such that existing spring force is maintained, and position 3
provides a "rough road" setting that raises the car 2 inches.  The owner's 
manual  states that the car should never be put on a lift, with all four wheels
off the ground, without first selecting position 2.  Furthermore, position 2
can not be used for driving.  Either mis-use will damage the suspension.
Perhaps the federal laws did not allow the drop test to be done with switches
set for anything other than the normal driving state.

(One side effect of the air suspension is that after a sudden temperature drop
(of 30 degrees or more), the car is sitting on its tires, looking like a
low-rider.  It then takes a minute or two with the engine going to pump itself
up.  Also, the compressed air tank has to be bled of condensed moisture,
using a whip cream can type of nozzle under the front bumper, every couple
of weeks or so.)

Bob Schleicher
ihuxk!rs55611