In article , The Other Mike
scribeth thus
On Mon, 24 Sep 2012 20:27:52 +0100, tony sayer wrote:


I remember driving a rather olde Lotus many years ago that had vacuum
headlamps .. foot to the floor lamps down.. Back off the power lamps
up;!...

Sort of inbuilt speed limiter I suppose;!...

You had a faulty non return valve in the vacuum line. The biggest problem is
raising the lamps at high speed as it is very easy for them to overtravel and
crack the fibreglass on the body.


Look that was a Lotus and it was going, moving!, what more can you
expect from one;?..

As Colin Chapman once said..

"If it hangs together for more than once race then we've built it too
well"!...

Early cars used vacuum to raise the lamps, later ones moved to failsafe lamps
that were raised by a spring and needed the vacuum to stay down.



--
Tony Sayer