generator problem

[oldply]

Thanks for all your help.
It ended up being a shorted wire that went through the fire wall. The previous owner ran wires through the firewall without using a rubber grommett and they shorted out. I got a wiring diagram from 1eZwire which was very informative. The generator being the problem didn't seem right that's why i asked. This is my first antique car and so far it's been a lot of fun getting things right.
Jay

[Captain Cranbrook]

Sounds to me like there's a short in your brake light or tail light wiring.? The reason your headlights dim then go out is because the the circuit breaker on your headlight switch opens due to the excess current it's experiencing.? After you release the brake pedal the short disappears and the breaker cools down so your headlights work again.? The stoplight switch is spliced into the brake line going to the rear of the car under the chassis.? Look at all the wires going rearward from the stoplight switch and see if there are any spots without insulation or rubbing the metal that could create a short.? Hope this helps.

[Go Fleiter]

Dear Jay, the brake bulbs do not consume as much current as this alone should dim the headlights to dark. Check headlight?s ground first by bridging Batt ground (beware: can be plus or minus grounded!) to the lamp!

  Easiest than is measuring the output in Volts at 1.) generator 2.) regulator 3.) battery (after a long loading pause) under different conditions (i.e. brake lights on / off running engine etc..).

  Turn lights consume much more current because of the flasher relay, this is good for testing the overall performance of the system.

  Next I would bridge the brake light cables with new ones. Take same gauge wire. If this does not help, disconnect both sides of the old cable, as it may have weak insulation.

  While letting the brake light switch in its place, I would next try to connect its cables to another one.

  Often the regulator is not working well. Its mechanical parts wear out. You find a good procedure instruction in the service manuals.

  Beware while experimenting: The generator can burn every bulb (and Radio!) if not regulated properly. It can give 20- 30 Volts! The regulator itself performs very differently at different temperatures. I got my regulators (I always carry one spare regulator (and a lot of other spare parts) with me while travelling) trimmed while running the engine for almost ? hour. They heat up themselves and deliver 6.5 V when cold and up to 8.2 V when hot. Remember not to bother Your neighbours?.do it on a lonely place

  Not only the aging insulations of the harnesses of our cars often cause problems, think of the connectors and switches too. If needed: put additional heavy gauge Ground cables in all four corners of Your car.

  It is possible to understand car electricity. Ignition physics in iron and wet and greasy conditions is even more complex. If You don?t like to learn all this, ask a competent friend for help. I found it very rewarding to go into this deeply.

  Greetings and good luck!   Go.   

[Bob Kinker]

Possibly the generater is not working right, but I would start looking for grounded wires going to the taillights! 

[oldply]

Hi, I own a 53 Cranbrook. My problem is when i step on the brake with the headlights on the headlights go dim and if i hold the brake down a little longer they go out . When i let go of the brake the lights come back on. I was told I need the generator rebuilt, does that sound correct ? What is the best way to check the generator to be sure ?
Thanks, Jay