One thing that will slowly discharge a battery is grease, dirt and
moisture between the posts. I did'nt really belive this until an old
timer took a digital multimeter and showed me a voltage reading between
the neg post and the plastic top of a really dirty battery.
On removing the negative first, it's to prevent sparks around the
battery. If you take off the positive first (unless it's a early gmc)
and you touch the wrench to any surrounding metal you'll get a pretty
big spark (voice of experience!). A battery produces Oxygen and Hydrogen
(Remember the Hindenburg?) as a result of charging or discharging. If
there is enough around and you make a spark there can be acid ALL over.
I remember when JC Penny came out with a lifetime sealed battery in the
70's, only problem was: it wasn't a gel cel, it was a normal lead acid
battery. I guess they figured by the time the electrolye got low people
woould have traded the car or lost the receipt. Well they started
blowing up. The electrolyte dropped way below the plate level and caused
more outgassing, then under load a plate would short, KaBoom!! I had
one blow up on me and when I took it back they put it on this whole pile
of returned shattered batteries. Can you say fiasco? They discontinued
them shortly.
--
John Dorsey
Wauchula, FL
'49 Chevy Panel http://www.strato.net/~jrdorsey/truck.htm
'52 GMC Firetruck http://www.strato.net/~jrdorsey/fire/fire.htm
'51 Chevy suburban http://www.strato.net/~jrdorsey/burb/
jls wrote:
>
> This brings up an interesting question I've had for years.
> Why does the repair manual allways tell you to disconnect the negetive
> lead from the battery when making repairs? Is there some reason
> disconnecting the negative leads is better than disconnecting the
> positive?
>
> Thanks,
> -JLS
> oletrucks is devoted to Chevy and GM trucks built between 1941 and 1959
oletrucks is devoted to Chevy and GM trucks built between 1941 and 1959
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