Pontiac FIREBIRD 1972 Service Manual page 1294

12-24 1972 PONTIAC SERVICE MANUAL
not connect cirectly to negative post of dead battery)
- taking care that clamps from one cable do not inad-
vertently touch the clamps on the other cable. Do not
lean over the battery when making this connection.
Reverse this sequence exactly when removing the jumper
cables. Reinstall vent caps and throw cloths away as the
cloths may have corrosive acid on them.
WARNING: Any procedure other than the above
could result in: (1) personal injury caused by elec-
trolyte squirting out the battery vents, (2) per-
sonal injury or property damage due to battery
explosion, (3) damage to the charging system of
the booster vehicle or of the immobilized vehicle.
Do not attempt to jump start a car having a
frozen battery because the battery may rupture
or explode. If a frozen battery is suspected exam-
ine all fill vents on the battery. If ice can be seen,
or if the electrolyte fluid cannot be seen, do not
attempt to start with jumper cables as long as
the battery remains frozen.
PERIODIC SERVICE
Battery care is extremely important. It should receive the
following attention:
1. Check the fluid level in each cell of battery every two
months. If low, add distilled water to bring level to
bottom of split ring in cell filler well.
CAUTION: Do not overfil battery and never
add any substance to fluid except distilled wa-
ter.
2. Keep battery, battery cable clamps, and battery hold-
down bracket clean. Cleaning should be done with a
brush and a solution of ammonia and water or baking
soda and water. Flush off with clear water. After
cleaning, apply petroleum jelly or petrolatum to bat-
tery cable clamps and terminals to retard corrosion.
NOTE: Apply petrolatum or petroleum jelly
AFTER connecting battery cables.
3. If battery performance becomes questionable, check
the battery.
INSPECT
Check outside of battery for damage or signs of serious
abuse such as broken case or broken covers. Check inside
of battery by removing vent caps and inspecting for signs
of abuse such as electrolyte level too low or unusual odors.
If battery shows signs of serious damage or abuse, it
should be replaced.
SPECIFIC GRAVITY CELL C O M P A R I S O N TEST
The hydrometer test will indicate the state of charge of a
battery unless water has recently been added to the battery
or the battery has been recently fast charged. A good
hydrometer reading does not necessarily indicate that the
battery will perform its normal functions.
The specific gravity of the electrolyte, as measured by the
hydrometer, must be corrected for temperature for a true
specific gravity reading. The thermometer is used to meas-
ure the temperature of the electrolyte in the center cell of
the battery. Based on this temperature reading, the spe-
cific gravity reading of each cell is corrected by adding
.004 points for each 10" above 80°F. or subtracting .004
points for each 10" below 80°F.
Examples:
a. Hydrometer gravity reading
................................
.1.235
Electrolyte temperature
.................................
.I 10°F.
Correction (4 x 3)
.............................................
+
.012
Corrected gravity reading
..................................
.1.247
b. Hydrometer gravity reading
................................
.1.250
Electrolyte temperature
......................................
.0"F.
Correction (4 x 8)
............................................
.-.032
Corrected gravity reading.
.................................
. I
.2 18
1. Visually inspect the battery for a broken or cracked
case, broken or cracked cover, odor, leaks around
damaged terminal posts, etc. If severe damage is
found, replace the battery.
2. Measure the specific gravity of each cell in the battery
and the temperature of one of the center cells. Inter-
pret readings as shown in Fig. 12-26.
NOTE: If the electrolyte level is too low to be
checked by a hydrometer, aadjost electrolyte to
the proper level by adding colorless, odorless,
drinking water. AAer water addition, the spe-
cific gravity check cannot be made until the
battery is charged at a rate high enough to
cause vigorous gassing for a period of I5 mi-
nutes or more. This insures that added water is
mixed with the electrolyte before a specific
gravity reading is taken.
3. Fully-charge and re-test those batteries which pass
the specific gravity test but fail to perform satisfac-
torily. Any cell indicating a specific gravity reading
(corrected for temperature) of less than 1.230 means
that the battery is defective and should be replaced.
421 TEST
The 421 battery testers (Fig. 12-27) are available to test all
solid-top batteries or other conventionally- constructed 12
volt batteries. These 42 1 testers, manufactured by various
test equipment companies, will in 2 or 3 minutes deter-