Dan,
Thanks for that explanation! Makes sense, my logic was faulty, and not the
switch!
So my switch does work, and it was just out of alignment! The housing that
the switch goes into was kinda loose. Now all I have to do is get it on
there correctly and make sure it lines up to the pedal correctly. Whew!
Dan
'73 B
-----Original Message-----
From: DANMAS <DANMAS@aol.com>
To: danray@bluegrass.net <danray@bluegrass.net>; mgs@autox.team.net
<mgs@autox.team.net>
Date: Thursday, April 23, 1998 8:49 PM
Subject: Re: '73 B Brake Light Switch
>In a message dated 4/23/98 9:19:12 PM Eastern Daylight Time,
>danray@bluegrass.net writes:
>
>> Logic tells me that the when the plunger to the brake light switch is
>> DEPRESSED, the lights should go ON.
>> My brake lights were staying on, so I removed the switch from the
housing
>> and fiddled with it, pulling the little plunger out and pushing it in.
At
>> first, the lights just stayed on, then they started going off when I
>> RELEASED the plunger...
>> Anyone seen this before? Or Is this a Lucasism where the switch needs to
be
>> aligned so that the pedal, when depressed, releases the plunger?
>
>Dan,
>
>No, this is not a "Lucasism," every car works that way, unless it has a
>pressure switch in the brake lines. It has to be this way, nothing else
would
>work.
>
>You want the brake lights to come on as soon as you depress the pedal, not
>just when the pedal is depressed all the way. Most of the time, you never
>press the pedal all the way anyhow. If the switch worked the other way,
the
>lights would only come on at the bottom of the pedal motion, meaning they
>would never be on except in a panic stop. If the switch were arranged to
come
>on at an intermediate point, either the switch would break when the pedal
was
>fully depressed or the pedal would be limited in its travel (I'm sure there
is
>some Rube Goldberg arrangment to allow this, but no simple setup).
>
>The brake pedal is pivoted at the top. When you press the bottom forward,
the
>top moves towards the back of the car, releasing the switch and lighting
the
>brake lights. The switch contacts close as soon as the pedal is depressed
>just a little bit. The switch needs to be adjusted very carefully, or it
will
>preven the pedal from retracting fully, dragging the brakes. This happens
>fairly often when people replace the switch, or do other work on the pedal
>assembly.
>
>Evidently, your switch was adjusted too far out. When the pedal was
released,
>it still did not make contact with the switch.
>
>If a car has the switch in the brake lines, operated from hydraulic
pressure,
>then it needs to turn on when the pedal is depressed. As long as the
switch
>is properly mde to withstand the pressure, it will not be damaged by a
panic
>stop, yet will operate in a gentle stop.
>
>I had a problem with the brake switch in my TR6 failing frequently, so I
>replaced it with one from GM and have had no troubles since. As I said,
all
>brake switches work this way, so if you can find one that will physically
fit,
>there is no reason you can't use it. I walked into the local auto parts
store
>with the Lucas switch in hand and asked the counterman to find me one like
it.
>he brought out about a dozen or so, and I picked one that would work. I
had
>to file a flat spot on the threads, but other than that, it was a simple
one
>for one swap.
>
>Dan Masters,
>Alcoa, TN
>
>'71 TR6---------3000mile/year driver, fully restored
>'71 TR6---------undergoing full restoration and Ford 5.0 V8 insertion -
see:
> http://www.sky.net/~boballen/mg/Masters/
>'74 MGBGT---3000mile/year driver, original condition - slated for a V8 soon
>'68 MGBGT---organ donor for the '74
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