View Full Version : Electrical: Brake lights

07-07-2017, 12:07 PM
The brake lights on my 62 GT Hawk are bright but I have to push the brake pedal real hard to get them to come on. I checked the volts at trunk and there is only about 3 volts showing. Question is, will the lights come on with less pressure on the pedal with a new switch? And does the 3 volts indicate a poor switch?
Thank you to any who can help!


07-07-2017, 01:38 PM
Should be "close to" 6 or 12 volts depending upon the battery your car uses. A new switch should help. If originality isn't important and you are handy it is better to have a mechanical switch. Based on your picture I assume you have floor pivoting pedals which are harder to fabricate for. Most of the pressure switches are mounted on the bottom of the master cylinder. If you can plumb it so it is vertical, with the electrical connector facing up it helps to avoid accumulation of debris that is often the downfall of these switches.

07-07-2017, 06:48 PM
Thank you Wittsend. I bought a replacement for $11.00 at O'rielly's today. I could not find the location yesterday until I read the manual. It is located near the steering gear. I can replace it by reaching down over the fender. And it sits up with the connectors facing up. Have a nice day!!

07-07-2017, 09:31 PM
The unknown name and location poster in Post #2 is recommending that you replace the Troublesome Hydraulic Switch with a normally closed, Mechanical one that is really not that hard to mount on the bottom of the floorboard to catch the returning Pedal Arm and cannot fail as these poor quality Hydraulic ones we now get from Mexico & China always do, much faster with DOT 5 Silicone Fluid.

07-08-2017, 12:46 AM
Thank you for clearing up the 2nd post. As I stated above I did buy another switch like the one on the car. I hope to test it tomorrow. If I have trouble with it again, I will consider the type he suggested. I am sure that I can make it work.:)

07-08-2017, 07:43 AM
Before you install the wires clean the inside of the female bullet connector, i use a .22 caliber bore brush. Luck Doofus

07-08-2017, 08:48 AM
A year or two ago, (coulda been longer), I took a failed hydraulic switch apart, mainly to study their construction. I already had a good idea of just how they were constructed, but wanted to examine the switch construction closely to see if I could gain a better understanding of why they fail. There are two chambers. One wet, (brake fluid side), and the other dry, (electrical contact side). I was thinking that what I would find was that the rubber seal had failed and brake fluid in the dry side. That was not the case. Instead, what I found was corrosion forming on the contact (dry) side. Since then, I have examined a few other switches. None of them had brake fluid in the contact area.

I believe the failure is due to a lack of quality control of "atmosphere" in the assembly area while the contacts are being installed. It is my belief, that if the switches are assembled in an open area, what ever the humidity, or contamination is floating in the air, it ends up being captured and sealed up in the electrical contact side of the switch. In fact, that side, once assembled, is the most "sealed" part of the switch. The wet side does not get sealed until installed on a car. Therefore, if the switch is constructed with no consideration of the "workplace contaminated room air"...the electrical contact area could begin to corrode, due to the entrapped contaminated air, immediately.

I believe, that if the switches were assembled in a laboratory "clean room" environment, failure would be extremely rare. Pressure switches are in all kinds of systems, working reliably to control fluids from pie fillings, paints, and harsh solvents. Our old conventional hydraulic automotive switches are probably being assembled in hot dirty "sweat shops" with little attention to the quality of air (or dirty sweaty fingers) contaminating those tiny contact components.

07-08-2017, 10:26 AM
If you choose to consider installing a mechanical brake light switch, here is how I did mine in a '54 sedan (which also has the underfloor brake pedal): http://forum.studebakerdriversclub.c...itch+sedan :// (http://forum.studebakerdriversclub.com/showthread.php?48294-Mechanical-Brake-Light-Switch-(Underfloor-Pedals)&highlight=brake+switch+sedan ://)

07-08-2017, 11:07 AM
It was interesting to see the inside of the pressure switch. I'm sure that you are correct about the atmosphere they are assembled in. It would add a few cents to the cost of manufacture, but a little dielectric grease on the contacts, would make them last much longer. I'm sure that we've all seen the older version of these switches last for fifty years or longer, vs two or three years on the repops.

07-10-2017, 09:43 PM
Thanks so much for the information and the picture. I was wanting to take one apart but didn't want to take the time. Also, I agree with the idea about their being constructed in a poor environment. Thank you again.

07-11-2017, 10:25 AM