THE PROBLEM:
The original switch that operates the brake lights on a Healey (and
many other older cars) is a hydraulic switch. This means that
pressure from applying the brakes is what makes the switch work, and
subsequently what makes your brake lights work. This isn't exactly a
good way to do it, as it means that you're well into pressing on your
brake pedal before the guy behind you sees brake lights. By
contrast, on a modern car, your brake lights are coming on nearly the
instant you start pushing on the pedal... letting the person behind you
know even before you're braking that you're about to. In today's
modern traffic, that difference in actuation time could get you rear
ended! On top of this, hydraulic pressure switches tend to lose
sensitivity over time, requiring even more brake pressure to activate
the switch. This makes things even worse - certainly a bad
scenario for something as important as brake lights.
THE SOLUTION:
The solution is simply to update to a modern mechanical switch.
There are lots of options for doing this... you could find an OEM switch
off some modern car that you're familiar with, or you could do what I
did, and get an aftermarket universal switch.
The switch that I got is a small lever-type switch
that I purchased from
gearheadworld.com. It was originally intended for
old street rods, but works just as well on a Healey. Just do a
search on their site for "brake switch" and you'll find it... called a
"Universal Street Rod Adjustable Brake Light Switch". Here's what
it looks like....
This switch has an adjustable lever arm (the reason I
chose it instead of something OEM) with a
plastic bushing sticking out, which is the part that would rest against
the brake pedal. It's a normally closed switch, which means that
it normally wants to turn your brake lights on, and it's the force of
your brake pedal pushing against the arm that keeps them turned off.
The hardest part of doing this is actually mounting
the thing. I mounted mine to the back side of the metal airflow
box that runs right behind the pedals. This meant I essentially
had to mark and drill backwards... shoving my body under the dash,
holding the switch in position, and using a mirror to mark the hole locations
and drill. Fun :) I could only get one of the holes marked
and drilled from the back side - the lower one. And even that was
a real bear... drilling a smaller hole than what I would ultimately need. Then, on the bottom of the airflow box, there's a
flip-open heater vent door right above your feet. Well, the whole
door mechanism is just attached with a couple screws. Removing the
door, I could then see the one starter hole I
drilled, and could finish marking and drilling from this direction. It
was NOT easy, but I just took my time and was very careful with my
drilling. Because I was drilling at such a steep angle (since
there's no straight shot to this location), I actually carefully
finished out the hole size using a Dremel tool... taking a little bit of
material out, holding up the switch to see where I was at, taking some
more material out, etc. It took a while, but worked great - I was
able to mount the switch with the bolts coming in from the switch side,
and then using a nut and lockwasher on the inside of the airflow box.
Here's what the switch ended up looking like once mounted (with some
notes added to the photos). Note that these photos were taken off
a mirror, as it was the only way I could capture it....
You'll notice that I modified the original lever
"leg" piece to angle it over a bit - it was the only way to get the
roller lined up with the pedal, given my mounting location. Here's a different angle, where
you can see the roller against the brake pedal...
I call it a "roller" because I ended up modifying the
original plastic pin slightly. I left the pin in place, but then
fit another plastic piece over the top of it, with a washer on one end
to hold it in place, while the other end was held in place by the lever
itself. This portion I added could then actually roll as the brake
pedal moved. I figured this would be a better way to do it - a
larger contact surface, plus reduced friction. I coated the I.D.
of my add-on roller with some Viper Lube before I slipped it on, to keep
it spinning freely.
From there, it was just a matter of working out the
wiring...
The original switch wiring worked off the key - the
key had to be on in order for the brake lights to illuminate. I
wanted to change this (modern cars have always-powered brake lights) so
I did some additional wiring changes.
I already had a big always-hot wire set up from doing
my headlight modification, so I just spliced into that wire to connect
to one side of the brake switch. Then the other side of the switch
went out into the engine compartment, following the original harness,
and connected into the existing brake wire junction that's against the
wall (right next to the brake master cylinder).
Once the switch was all powered and working, then I
adjusting the bracket position as needed to get the switch to actuate
just as I pressed the brake pedal. I used my daily driver Volvo as
a reference... pressing on that brake pedal to see how quickly the brake
lights came on, and then setting a similar "feel" in the Healey.
And for added comfort....
Me being paranoid about messing with this kind of
stuff, I liked the idea of having a backup plan in place, in case the
new switch failed for some reason. So I decided to keep the old
pressure switch functioning, and hook it up in parallel to the new
switch. That way, they're both still functioning, just in case the
mechanical switch quits working. HOWEVER... if you do this, don't
forget that the original switch ran off ignition power, so you'll have
to change this to match the new switch. If you DON'T change it,
then when the pressure switch actuates, you'll actually be completing a
circuit to your ignition, meaning it would be just like turning the key
on. Definitely not something you want to happen just from pressing
the brake pedal :)
At the pressure switch then, I simply disconnected
and capped off the original ignition power wire, and then ran a new wire
from my always-hot connection, following the original wiring harness
(and taking care to make sure the wire was both hidden and well
protected, as well as in no danger of being able to rub through on
something due to vibration). Then the other wire from the
switch, well, that already goes where I need it - to the junction on
the engine compartment wall. So I just made a little 3-way
connection block at that location... connecting the wires from both the pressure switch
and mechanical switch to the original wire heading back to the brake
lights.
Here's what the wiring sorta looks like, in case that
was a bit confusing...
If anyone has any questions about any of this, feel free to send me an email!
