VCCA Home
Posted By: 6wheel 1931 6V brake light bulb - 09/07/16 07:49 PM
In the last month I have replaced both #87 brake light bulbs twice in my '31 coupe. I've only driven about 30 miles since I replaced them last time. I just happened to check and found they were out again today. The ones that blew were GE, and I replaced this time with Wagner. I'm using YnZ's turn signal kit which is part of my harness. The front signal lights are in the cowl lights. The bulbs in the cowl lights have not blown in the 8 years the car has been restored. Any thoughts?
Sid
Posted By: Junkyard Dog Re: 1931 6V brake light bulb - 09/07/16 08:50 PM
Check for a bad ground, bad light sockets or a short in the wiring.

laugh wink beer2
Posted By: 6wheel Re: 1931 6V brake light bulb - 09/08/16 07:03 PM
Sockets and ground checked out okay, but generator is putting out 10 volts. Will try to adj third brush. Thanks
Sid

Posted By: 6wheel Re: 1931 6V brake light bulb - 09/08/16 07:47 PM
Finally figured out how to move brush. Generator now putting out 7.8 volts max. Hopefully, this will stop bulb blowing. I don't know how to secure brush. The screw on back of generator is tied to a bracket inside, but the bracket is no where near the new location of the brush.
Sid
Posted By: Bill Barker Re: 1931 6V brake light bulb - 09/08/16 08:57 PM
[Linked Image from 1931chevrolet.com]


Instructions are Available HERE.

REMEMBER: Move DOWN to go UP. And UP to go DOWN.
(Move brush DOWN to Increase Voltage, and brush UP to lower voltage.)
Posted By: 6wheel Re: 1931 6V brake light bulb - 09/09/16 01:41 AM
Thanks Bill, I'd seen similar picture in manual. I guess I need to study that part of the generator more closely. I moved the brush by using a screw driver like a pry bar. The screw shown in the picture on the back of the generator fastens a small plate on the inside, but it doesn't appear to attach to anything.
Sid
Posted By: Junkyard Dog Re: 1931 6V brake light bulb - 09/09/16 01:58 AM
Quote
The screw shown in the picture on the back of the generator fastens a small plate on the inside, but it doesn't appear to attach to anything.

The plate doesn't "attach" to anything...instead it holds pressure on the third brush bracket so that the third brush doesn't move after the screw on the end frame is tightened down. Check inside of the generator to make sure that the plate is on top of the third brush bracket to hold it in place.

laugh wink beer2
Posted By: 6wheel Re: 1931 6V brake light bulb - 09/14/16 05:24 PM
I found a spare generator in the attic. Its third brush has a bronze bracket that is secured by the clamp like the Dog days. The third brush on the generator on my 31 does not have this bronze bracket, or maybe not all of it. It seems very secure without being tied down. I had to move it by prying with a screw driver, and after driving 20 miles yesterday, it hasn't moved. The lower voltage is a good thing too. So far no more blown bulbs. Thanks guys.
Sid
Posted By: 6wheel Re: 1931 6V brake light bulb - 12/14/16 06:58 PM
I've driven the '31 about 150 miles in the last few months, and I noticed after a short drive that it was making about 7 amps at idle. Checked the stop light bulbs and found that both were blown again. I plan to have my spare generator checked out, and if it's okay I'll run it, since it's third brush appears to be complete.
Posted By: Chev Nut Re: 1931 6V brake light bulb - 12/14/16 08:08 PM
The amps will not blow the bulbs. Too many volts will do that.
Posted By: 6wheel Re: 1931 6V brake light bulb - 12/14/16 08:11 PM
Thanks Gene. I'll check the generator output again. I presume the third brush has slipped again.
Sid
Posted By: Junkyard Dog Re: 1931 6V brake light bulb - 12/14/16 09:19 PM
If the clamp for the third brush is tightened down correctly the third brush should not slip.

laugh wink beer2
Posted By: Chev Nut Re: 1931 6V brake light bulb - 12/14/16 09:20 PM
Check the voltage, Run engine for about 20 minutes at least fast idle) and it sould be around 7.5 volts.
Posted By: 6wheel Re: 1931 6V brake light bulb - 12/22/16 08:22 PM
Generator output is still 7.5 volts. What else could blow bulbs? The bulbs fit very tightly in the reproduction taillight buckets. Maybe they are hitting the inside of the bucket as the car bounces. Also,every bulb I have used is made in China...am I the only one with this problem? I found 2 new bulbs in my stash with blown filaments. As another test I have a new working 87 brake light bulb in the left taillight bucket. We will see how long it lasts.
Thanks,
Sid
Posted By: Junkyard Dog Re: 1931 6V brake light bulb - 12/23/16 04:35 AM
Bulbs made in China are junk.

The generator output of 7.5 volts is perfect.

laugh wink beer2
Posted By: Tiny Re: 1931 6V brake light bulb - 12/24/16 09:45 PM
Some China stuff is OK but most is junk. I bought a dozen 2530 headlight bulbs that were made in China. The low beam would burn out within 5 seconds. The high beam would last a while. I threw them away and bought two dozen NOS bulbs I found on ebay. If it were me I'd put another Chinese in, lay a brick on the brake pedal, pull up my chair & see if they do the same thing. Watch them for 20-30 minutes without driving the car. See if they simply burn out like the junk ones I bought. Does the inside of the glass have the typical burn mark a burned out bulb makes? For what it's worth I've had pretty good luck with Chinese Wagner bulbs.
Posted By: 6wheel Re: 1931 6V brake light bulb - 01/09/17 08:16 PM
I ran the car at fast idle with left turn signal on the entire time. Bulb did not blow. Will continue to watch.
Thanks, Sid
Posted By: 6wheel Re: 1931 6V brake light bulb - 01/19/17 05:44 PM
Put new bulb in right side and drove car about 5 miles. Checked bulbs when I got home...both brake light bulbs where blown. There was no discoloration. The filament just had a short section missing. Installed new bulbs in both buckets. One is GE, other is Wagner. I also moved the sockets so that the glass part of the bulbs couldn't touch the bucket.
Posted By: 6wheel Re: 1931 6V brake light bulb - 01/20/17 03:25 PM
I tested it running in the garage for 30 minutes. I left the brake lights on for 15 minutes, flashed the brake lights for 5 minutes, and flashed the left and right blinkers for 5 minutes each. I also tapped on each tailight bucket several times. Both bulbs continued to burn. I'll test drive it when the weather breaks.
Sid
Posted By: Junkyard Dog Re: 1931 6V brake light bulb - 01/20/17 03:31 PM
Quote
Generator output is still 7.5 volts.

Is that at idle? If so, what is the generator output at speed when driving?

laugh wink beer2
Posted By: 6wheel Re: 1931 6V brake light bulb - 01/20/17 04:20 PM
It was at fast idle, and output was 7.5 volts.
Posted By: Junkyard Dog Re: 1931 6V brake light bulb - 01/20/17 04:30 PM
What is the output while driving at speed?? The output might be too high which would cause the bulbs to blow while you are driving.

laugh wink beer2
Posted By: 6wheel Re: 1931 6V brake light bulb - 01/20/17 04:43 PM
Thanks Dog. I'll check voltage at higher RPM.
Posted By: 6wheel Re: 1931 6V brake light bulb - 01/20/17 07:46 PM
Output voltage at high RPM is 7.85. I just test drove it for about 3 miles. Checked bulbs halfway and they were good. Drove rest of way home and they were both blown! Could the brake light switch do this? It is old, but works. The turn signal switch came with the harness from YNZ.
Sid
Posted By: a3alf Re: 1931 6V brake light bulb - 01/20/17 08:04 PM
If there is no burn marks and the filament is broken then the bulb is hitting something when driving.
Al
Posted By: 6wheel Re: 1931 6V brake light bulb - 02/13/17 11:34 PM
As I said previously, the tail light assemblies are reproduction. Considering Al's comment, I shortened the mounting brackets for the bulb sockets to make sure the bulbs couldn't hit the inside of the tail light buckets. I then replaced the bulbs for the fifth time in about 4 months. Since then I have driven the car about 15 miles, and neither bulb has blown. Looks like the problem is solved.
Thanks guys for all of your thoughts.
Sid
Posted By: 6wheel Re: 1931 6V brake light bulb - 04/12/17 03:00 PM
It happened again! I checked the brake lights and found that both rear bulbs were blown again. Could this be caused by the turn signal switch? I didn't use this switch for a few years while showing the car. I wanted it to look all original, so I hid the switch under the dash. This problem started since I mounted the switch on the column and began using it.
Sid
Posted By: Junkyard Dog Re: 1931 6V brake light bulb - 04/12/17 08:09 PM
Disconnect the turn signal switch and see what happens. If the bulbs don't blow when the turn signal switch is disconnected then you found your problem.

laugh wink beer2
Posted By: 6wheel Re: 1931 6V brake light bulb - 04/17/17 02:56 PM
Thanks Dog. We will see.
Posted By: Junkyard Dog Re: 1931 6V brake light bulb - 04/17/17 02:59 PM
Let us know what happens.

laugh wink beer2
Posted By: 6wheel Re: 1931 6V brake light bulb - 05/30/17 06:54 PM
I found the wire for right rear was loose in the turn signal switch. I re-soldered it and reassembled the switch. Hopefully, this will solve problem.
Thanks,
Sid
© Vintage Chevrolet Club - Discussion Forum