Archived sparks when using the brake spoon to get rubber inspection cap off backing plate

[TComparetta]

Any ideas why I would see sparks shoot out from my rear metal backing plate ??? When I was going to inspect the rear shoes, was using the brake spoon to get the rubber inspection cap off the backing plate, when I slipped with the spoon, sparks shot out of the backing plate. i did it several times just to make sure i wasn't crazy, sparks shot out every time like i was grinding or welding.. if anyone has any idea why this strange thing would happen, please reply.. I have to make a long trip soon and would like to figure out the issue so I am safe on the road.. thanks.. i have a 99 dodge ram 2500 4x4

 

[DavidC]

When the sparks flew what 2 points was the spoon touching ?. The brake hose is rubber ( never tested brake fluid to see if it is conductive ), your spring bushings are rubber unless they are worn out ), your shocks have rubber bushings ( unless worn out ). I think the rear axle would be isolated electrically except for the drive line. The only electrical on the differential is the speed sensor. If you have a voltmeter set on DC and starting at 20 volts you could attach the probes to the points the spoon touched to see what kind of voltage you actually have and the polarity of that voltage ( which is positive and which is negative ). Unless someone has better ideas I would start there.

Dave

 

[seafish]

Assuming that you have one, maybe one of your trailer plug wires is grounding to the frame or rear axle...check the condition of thew wires as they go to the plug and also as they run near the axle.

 

[Bob4x4]

dont rule out static electricity

 

[DavidC]

dont rule out static electricity

I kind of thought about that also but dismissed it when it was stated it was done several times. But you never know, worth considering anyway as nothing is ruled out yet. The part that is a little confusing is that the drive shaft should be grounded through the trans, engine etc. which should ground the differential which would leave the brake backing plate a positive potential. I can not quite figure that one unless as you state, static electricity.

Dave

Dave

 

[TComparetta]

thanks I will check all clues, and welcome more replys.. I just thought to mention that the wheel and tire was off, and the spoon touched the drum.. maybe that will be a bit more help to my issue.. many thanks to all....

 

[Bigiron]

I would start by pulling all fuses and check it then. Then pit them back one by one and check every time. If you have power with no fuses I would then assume wires to the trailer plug or wiring to starter or alternator. Can't think of any other power source that it could be. Let us know if you find it. Good Luck.

 

[B.G. Smith]

The brake spoon is a hardened steel, my thought is that you just sparked the backing plate when you struck it as in flint and steel. Might be some sort of oxide on the backing plate that caused it to be more pronounced. bg