The brake lights on my '49 Super are giving me a fit. About a year ago, they would stay on all the time, and eventually blew the fuse, which also controlled the turn signals. Replaced all the fuses with new ones, and installed a new brake light switch last week. The brake lights were working fine the first time I drove it, going off when the brakes were released. I drove the '49 this morning, and left it idling while I opened the garage doors to put it away after the drive, and noticed the brake lights were once again burning without the brake pedal being depressed. The turn signals are still working though. The car has been converted to 12 volts, by changing to a '56 Caddy generator. I got the brake light switch at my local NAPA, which was listed as the correct one for the car. Could it be sticking because of 12 volts running through it? Or could this be a ground problem somewhere? Frustrating!

I don't see how your problem could be related to running 12 volts as 6 volt switches and wiring are more than sufficient to handle 12 volts. I don't see grounding as a problem, either. If the ground was faulty the lights wouldn't work at all. Have you flushed the brake system and changed the brake fluid? The only thing I can think of that would hold a brake switch of this type engaged is old, gunky fluid that is so thick the spring action in the switch isn't allowed to release. I would try flushing the system and adding fresh brake fluid.

Thanks for the input...this could definitely be a oossibility. The master cylinder was rebuilt about a year ago, but the system wasn't flushed...only enough fluid was added back to replenish what was lost while doing the rebuild.

Hi, How much brake fluid is in the mater cylinder. If it's full to the brim, pressure may be building up as the heat from the wheel cylinders increase. This is just a theory. The next time your brake lights stay on pull one leg off the stop light switch, and see what happens. In my mind, if the brake lights stay on because of a faulty switch. They should stay burning until the battery goes dead, or a bulb burns out.... not blow a fuse. Make sure the style bulbs that were used, are the same. The only difference should be, one is 6V., the other should 12V. Did your signals work fine before the 12V conversion? If my memory serves me right, there should be two different bulbs in the tail light. One for stop/tail lights(which is double contact for stop, and tail), and the other for signals, single contact. If I'm wrong about the two bulbs, and there's only one bulb in the tail light, then your problem is in the signal light switch. Think about it, and take your time with it. It's something simple. Think about how everything worked before the 12V conversion, and go from there good luck!!! Also, back in those days, they used double contact bulbs for the dome, and courtsey lights. One contact was for the ground, and the other was for the current flow. Some time after, it was changed. The body of the bulb is now used for the ground, and the contacts on the rear of the bulb is for the current flow. This may be an issue as well. I can't tell you what bulbs # to use.

I ran your question past a friend, who is a great mechanic and has done a few restorations, including a '51 Special, and this is what he said:

Your brake lights go though your turn signal switch. When you move the lever for right or left it breaks the connetion for brakes and switches over to the hot wire from your flasher making your brake light a turn signal. You also have a wire going to the front to make it blink. If you are using the original 6 volt flasher, change it to a 12 volt, there is a difference. Also, while you have the steering wheel off checking the turn signal switch, give a look at the wiring in the column.

If I'm wrong about the two bulbs, and there's only one bulb in the tail light, then your problem is in the signal light switch. Think about it, and take your time with it. It's something simple. Think about how everything worked before the 12V conversion, and go from there good luck!!! .

There is only one bulb in each tail light.

All of the 12 volt conversion was done before I got the car, so I do not know exactly what was done. I do know that it had new wiring installed and that the light bulbs were all changed. You may be right about the turn signal switch being the culprit...the 6 volt flasher is still on the car, but the signals flash too quickly. We tried to match up a new flasher at a couple of auto parts stores, but all we could find were the square type that would match the blades on the old flasher. We tried installing one of them, but the signals would not flash. I've got the old 6 volt flasher back in it now, but the signals flash far too fast.

About the flasher, try putting a resistor on the feed wire that goes to the flasher. Remember, it's a 6V flasher and your feeding it 12V's The resistor will calm down the flashing intervals. Start with a 300 ohm resistor, and go from there. If 300 ohms is too much, get a 200 ohm resister. Go to your local electronics store and check it out. This may help because on your heater motors, it's a resistor that controls your fan speed. See what happens, and let me know. We can all learn something together.

Straight80

About the flasher, try putting a resistor on the feed wire that goes to the flasher. Remember, it's a 6V flasher and your feeding it 12V's The resistor will calm down the flashing intervals. We can all learn something together.

Straight80

Thanks for the idea! Sounds like a trip to Radio Shack for me! And you are exactly right, we can ALL learn something together here. I love this site, it's a wealth of information! So many people here have helped me with getting the '49 back on the road, I truly appreciate it.
:shifter:

The brake lights on your Buick are on a separate circut and do not go through the turn signal switch. The problem is most likely the brake light switch sticking and since the switch only recieves power when the key is on it will not run down the battery. It is possible your system may need to be flushed as a previous post suggested but it is more likely you have a new switch that is sticking. Try to get a switch that was made in the USA rather than an off shore part.

Your flasher can be replaced by any 2 or 3 prong heavy duty 12 volt flasher and they still sell the proper unit at any NAPA store.

The brake lights on your Buick are on a separate circut and do not go through the turn signal switch. The problem is most likely the brake light switch sticking and since the switch only recieves power when the key is on it will not run down the battery. It is possible your system may need to be flushed as a previous post suggested but it is more likely you have a new switch that is sticking. Try to get a switch that was made in the USA rather than an off shore part.

Your flasher can be replaced by any 2 or 3 prong heavy duty 12 volt flasher and they still sell the proper unit at any NAPA store.

I got the brake light switch at NAPA, and it was their Echelin brand...which costs more as well, LOL. I went with it because I didn't want a cheap off-shore brake light switch. I know it's always possible to get a bad part, regardless of the manufacturer though. Probably the easiest thing to do is to get a replacement brake light switch at NAPA, and try a heavy duty 12 volt turn signal flasher too, as you mentioned. Thanks!

There is an alternative. Chevrolet from about 1949 through 1954 (someplace in there) used a mechanical switch which was actuated by the brake pedal. The switch isn't connected to the hydraulic circuit at all. Just remove the stock switch, screw a pipe plug into the hole, drill 2 small holes under the brake pedal and reroute the wires. Chevs of the '40's has them but your friendly neighborhood store may still have one on the shelf.

One thing I had forgot to mention, a stop light switch for a 53 Super, or Roadmaster are 12V switches. In 53, the Special was the only Buick that was still 6V. The connections are different, never the less. It's still 12V's. Just something I'd thought I'd mention.

Straight80

One thing I had forgot to mention, a stop light switch for a 53 Super, or Roadmaster are 12V switches. In 53, the Special was the only Buick that was still 6V. The connections are different, never the less. It's still 12V's. Just something I'd thought I'd mention.

Straight80

Now, there's an idea! I'll check NAPA's website and see if the stop light switches look interchangeable. Thanks! I had completely forgotten that the Supers and Roadmasters went to 12 volts in '53!

Just checked out NAPA, both the '49 Super and the '53 Super take the same stop light switch...at least according to their information. Same part number, ECHSL134. If that is correct, they must be designed to work on 12 volts...so perhaps I just got a faulty one? I suppose the best place to begin is to replace the switch again this weekend, and see what happens from there.

This gets more puzzling all the time!

I drove the '49 Super today. When I started it up, the brake lights were working normally...and would go off when the brake pedal was released. I drove about 1 1/2 miles to a gas station to fuel it, and left it idling while I was filling the tank. While I was standing there pumping gas, the BRAKE LIGHTS CAME ON BY THEMSELVES! When I got back home, I checked the lights again before I cut off the engine...they were still on. I let it sit (not running) about 10 minutes, cranked it up again, and the brake lights were off...for about a minute, then mysteriously came back on!

I haven't gotten another new brake light switch yet for it, and from the way it acted today, I don't know whether I should. Have any of you dealt with this kind of problem before?

Opps,

Go for another ride just for the fun of it, and see if your mysterious lights come "on" again. If they do, put your left, or right signal on just to see what happens. If the signal on one side works, and the other stop light stays "on". It has to be your stop light switch. Or you can unplug one leg off the stop light switch when they mysteriously come "on" again. I can't see the signal switch making both stop lights come "on" together, unless there's wires loose that are completing that circuit somewhere? That's weird!!! You have to experiment with the opportunities you have at the moment, don't let them get away. Oh boy.... I just sounded like eBay sent you an email, when I wrote, "don't let them get away"

Opps,

Go for another ride just for the fun of it, and see if your mysterious lights come "on" again. If they do, put your left, or right signal on just to see what happens. If the signal on one side works, and the other stop light stays "on". It has to be your stop light switch.

I tried that Sunday after I drove the car. I turned on the right turn signal, which flashed...and the left side brake light stayed lit constantly. Same deal when I tried the left side signal, the right brake light stayed on. The shop manual says that the brake and turn signal circuits work together, but doesn't address any problems like this.

The brake pedal is not hanging, I checked that and it is returning fully when released. I even stopped on a slight hill to see if the brakes were hanging or dragging at all...released the brakes and the car rolled easily without any drag.