Brake adjust now no spark

W

Willynch

Member
I adjusted brakes using the method in Les Andrews with the board to hold brake pedal at varying positions. I have tried this twice (I think the brakes need to be re-done) but each time the electrics stop making spark.

There is voltage up to coil. I took dash off thinking there was short at ignition switch or ammeter. Found nothing and car started again

Am I crazy?
 
You indicate it would not run but you had voltage at the coil. With this condition does the Ammeter wiggle when the motor is turning over via the starter? This indicates the primary side of the ignition circuit including wiring/ignition switch/points/distributor/coil are most likely OK.


If that is working then take a plug out, ground it to a clean head stud and see if you get a nice blue spark at the plug gap when turning the motor over with the starter and with the ignition switch on.


If the brake switch is shorted, turn off the ignition, and look at the ammeter to see if it is zeroed out, then check the brake light to see if it is off. If that is all ok press the brake pedal down and check the ammeter and also checkthe lamp to see if it comes on.
 
Despite the doubters it is very possible that a shorted brake light switch is causing this as Jetmek says.
 
30 Closed Cab PU said:
You indicate it would not run but you had voltage at the coil. With this condition does the Ammeter wiggle when the motor is turning over via the starter? This indicates the primary side of the ignition circuit including wiring/ignition switch/points/distributor/coil are most likely OK.


If that is working then take a plug out, ground it to a clean head stud and see if you get a nice blue spark at the plug gap when turning the motor over with the starter and with the ignition switch on.


If the brake switch is shorted, turn off the ignition, and look at the ammeter to see if it is zeroed out, then check the brake light to see if it is off. If that is all ok press the brake pedal down and check the ammeter and also check the lamp to see if it comes on.
Click to expand...


The ammeter "wiggle" test will only work on about half of Model As manufactured.

Those cars made before the end of 1929 when a service bulletin and factory wiring changes went into effect are not wired so that the ammeter will show the discharge when engine is turning over with the starter.

There is no way of knowing how many cars made before Dec 1929 had the Service Bulletin installed.

I suspect that MOST folks were not worrying about Service Bulletins when everyone was losing their job and the economy was going to hell.
 
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Benson said:
The ammeter "wiggle" test will only work on about half of Model As manufactured.

Those cars made before the end of 1929 when a service bulletin and factory wiring changes went into effect are not wired so that the ammeter will show the discharge when engine is turning over with the starter.

There is no way of knowing how many cars made before Dec 1929 had the Service Bulletin installed.

I suspect that MOST folks were not worrying about Service Bulletins when everyone was losing their job and the economy was going to hell.
Click to expand...


Attached is the change, involves moving one wire on the terminal box. If your ammeter does not wiggle when cranking with the ignition on and motor not running. Check for this wiring change.
 

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Benson said:
The ammeter "wiggle" test will only work on about half of Model As manufactured.

Those cars made before the end of 1929 when a service bulletin and factory wiring changes went into effect are not wired so that the ammeter will show the discharge when engine is turning over with the starter.

There is no way of knowing how many cars made before Dec 1929 had the Service Bulletin installed.

I suspect that MOST folks were not worrying about Service Bulletins when everyone was losing their job and the economy was going to hell.
Click to expand...
So true, and if you don't switch the coil power feed wire to the other side, then you can connect a volt meter or test light to the points terminal of the coil and ground, then watch for the needle to flicker back and forth or the test light to go on and off as the points contacts make and break the ground connection.


BTW, I've seen some distributors that didn't have a good ground to the head or body.
 
Tom Wesenberg said:
So true, and if you don't switch the coil power feed wire to the other side, then you can connect a volt meter or test light to the points terminal of the coil and ground, then watch for the needle to flicker back and forth or the test light to go on and off as the points contacts make and break the ground connection.


BTW, I've seen some distributors that didn't have a good ground to the head or body.
Click to expand...


About red above:
Thanks Tom that solves a mystery for me.

I use an old HeathKit meter with two clips across the coil terminals to check RPM (325 to 475 RPM) when setting up carb idle mixture adjustment.

I wondered why several guys told me that tach did not work for them when hooked across coil terminals!

About blue above:

Same here in fact that reminds me to replace the alligator clip wire from cowl ground to the spark advance lever on the coupe. Spark was really flaky until I did that.

That problem had me wasting many hours trying to fix carbs that were not broken! ;):D

It has been there for long time. Just too busy to replace it when it works!

Makes all kinda sense now!
 
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