1973 OPEL MANTA water

IoC-91973 OPEL SERVICE MANUAL
Figure OC-5 Brake Master Cylinder
I
Figure OC-6 Tire Rotation Methods
when the clutch pedal has in excess of 1
l/4 inch fr&
travel. See Figure OC-7.
Rear Axle
Change lubricant every
12,ooO miies when vehicle is
used for pulling a trailer.
Cooling SystemCheck at 12-month or
12,000~mile intervals, wash
radiator cap and filler neck with clean water, pres-
sure test system and radiator cap for proper pressure
holding capacity (tighten hose clamps and inspect
condition of all cooling and heater hoses). Replace
hoses every 24 months or 24,000 ,miles or earlier :if
checked, swollen or otherwise deteriorated.
Also each 12 months or
12,ooO miles, clean exteribr
of radiator core. Every 24 months or
24,OCO miles,Floor-Pan
-Clutch Pedal
Figure OC-7 GT Clutch Lash
drain, flush, and refill the cooline svstem with a new
coolant so&ion of permanent
6~; anti-freeze and
water for protection-of -20°F.
D-6 NOT REMOVE
RADIATOR CAP WHEN SOLUTION IS HOT
AND UNDER PRESSURE.
Wheel BearingsClean and repack front wheel bearings with a lubri-
cant as specified on the lubrication chart, Figure
oc-1.
Automatic Transmission FluidUnder normal driving conditions, change the trans-
mission fluid every 24,000 miles. Under unusual con-
ditions such as constant driving in heavy city traffic
during hot weather, trailer pulling, etc., this service
should be performed at
12,COO mile intervals.
General Motors DEXRON Automatic Transmis-
sion Fluid, which has been especially formulated and
tested for use in your automatic transmission, is
recommended. Other automatic transmission fluids
identified with the mark DEXRON are also recom-
mended.
Check the fluid level at each engine oil change
period. To make an accurate fluid level check:
1. Drive car several miles, making frequent starts and
stops, to bring transmission up to normal operating
temperature (approximately
180-190’F.)2. Park car on a level surface.
3. Place selector lever in “Park” and leave engine
running.

LUBRICATION AND MAINTENANCE OC-9
4. Remove dipstick and wipe clean.
5. Reinsert dipstick untip cap seats.
6. Remove dipstick and note reading.
If fluid level is at, or below the ADD mark, add
sufficient fluid to rais the level to the FULL mark.
One pint raises the level from ADD to FULL. Do
not overfill.
3OC8Figure OC-8 Automatic Transmission Dipstick
SAFETY MAINTENANCE
Brake Lines and HosesCheck for proper attachment, leaks, cracks, chafing,
deterioration, etc. Any questionable parts noted
should be replaced or repaired immediately. When
abrasion or wear is evident on lines or hoses, the
cause must be corrected.
Tires and WheelsCheck tires for excessive wear, nails, glass, cuts or
other damage. Make certain wheels are not bent or
cracked and wheel nuts are tight. Uneven or abnor-
mal tire wear may indicate the need for alignment
service. Tire inflation pressure should be checked by
the owner at least monthly, or more often if daily
visual inspection indicates the need.
Exhaust SystemCheck complete exhaust system and nearby body
areas and trunk lid for broken, damaged, missing orm&positioned parts, open seams, holes loose connec-
tions or other deterioration wiuch could permit ex-haust fumes to seep into the trunk or passenger
compartment. Dust or water in the trunk may be an
indication of a problem in one of these areas. Any
defects should be corrected immediately. To help
insure continued integrity, exhaust system pipes and
resonators rearward of the muftler must be replaced
whenever a new mufIler is installed. Use genuine
GM parts specified for the vehicle.
Engine Drive BeltsAdjust belts driving fan, alternator and other acces-
sories at first 4 months or
6,ooO miles of vehicle
operation. At each subsequent 4 month/6,000 mile
interval, check belts for cracks, fraying, wear and
tension. Adjust or replace as necessary. It is recom-
mended that belts be replaced every 24 months or
24,C00 miles, whichever occurs first.
Suspension and SteeringCheck for damaged, loose or missing parts, or parts
showing visible signs of excessive wear or lack of
lubrication in front and rear suspension and steering
system. Questionable parts noted should be replaced
without delay.
Safety Checks to be Performed by OwnerListed below are the safety checks that should be
made by the owner (items a thru t). These checks
should be made at least every 4 months or
6,ooOmiles, whichever occurs first, or more often when the
need is indicated. Any deficiencies should be brought
to the attention of your dealer or another service
outlet, as soon as possible, so the advise of a qualified
mechanic is available regarding the need for repairs
or replacements.
A. Steering Column Lock
_ Check for proper operat-
ion by attempting to turn key to LOCK position and
turning steering wheel with car stationary. Steering
wheel should turn as long as key remains in lock.
When key is removed steering wheel should lock.
Key should be removable only in LOCK position.
B. Lap and Shoulder Belts
- Check belts, buckles,
retractors and anchors for cuts, fraying or weakened
portions, loose connections, damage, and for proper
operation. Check to make certain that anchor
mounting bolts are tight.
C. Steering
- Be alert to any changes in steering
action. The need for inspection or servicing may
beindicated by “hard” steering, excessive free play or
unusual sounds when turning or parking.
D. Windshield Wipers and Washers
- Check operat-
ion of wipers, as well as condition and alignment of

CC-10 1973 OPEL SERVICE MANUAL
wiper blades. Check amount and direction of fluid
sprayed by washers during use.,
E. Defrosters - Check performance by moving con-
trols to “DEF” and noting
am$nmt of air directed
against the windshield.
I
F. Wheel Alignment and
Balabce - In addition to
abnormal tire wear, the need fbr wheel alignment
service may be indicated by a pull to the right or
!eftwhen driving on a straight and level road. The need
for wheel balancing is usually
iddicated by a vibra-
tion of the steering wheel or
se;+ tihile driving at
normal highway speeds.I
IG. Brakes
- Be alert to illumiriation of the brake
warning light or changes in braking action,
SUCK as
repeated pulling to one side, unusual sounds when
braking or increased brake pedal travel. Any of thesecould indicate the need for
brakk system inspection
and/or service.
H. Parking Brake and Transmission “PARK”
Mechanism
- Check parking brake holding ability by
parking on a fairly steep hill and restraining the vehi-
cle with the parking brake only.
eon cars with auto-
matic transmissions, check the holding ability of the
“PARK” mechanism by releasing all brakes after
the transmission selector lever hak been placed in the“P” position.
I. Glass
- Check for broken, scrritched, dirty or da-
maged glass on vehicle that
coulld obscure vision’or
become an injury hazard.
J. Lights and Buzzers
- Check all instrument panel
illuminating and warning lights,’ seat belt reminder
light and buzzer, ignition key
b&er, interior lights,
license plate lights, side marker! lights, headlamps,
parking lamps, tail lamps, brake lights, turn signals,
backup lamps, and hazard warding flashers. Have
someone observe operation of
&ach exterior light
while you activate the controls: The operation of
instrument panel warning lights is covered in the
“Starting and Operating“ section of your
Own&%
Manual.K. Transmission Shift Indicator
‘- Check to be sure
automatic transmission shift
indiCator accurately i”-
dicates the shift position selected.
I
CAUTION: Before making thk check below,I
be sure to have a clear dist&e ahead and:
behind the car, set the parking brake and
firmly apply the foot brake.
Do not depress
accelerator pedal. Be prepared to
turn off ’
ignition switch
immediat+y if engine
should start.L. Starter Safety Switch (Automatic Transmissibn
Cars)
- Check starter safety switch by placing the
transmission in each of the driving gears while
at-tempting to start the engine. The starter should oper-ate only in the Park (“P”) or Neutral (“N”)
positions.
M. Horn
- Blow the horn occasionally to be sure thatit works. (Ignition switch must be in the “ON” posi-
tion.)
N. Seat Back Latches
- Check to see that seat back
latches are holding by pulling forward on the top of
each folding seat back.
0. Rearview Mirrors and Sun Visors
- Check that
friction joints are properly adjusted so mirrors and
sun visors stay in the selected position.
P. Door Latches
- Check for positive closing, latch-
ing and locking.
Q. Hood Latches - Check to make sure hood closesfirmly by pressing on the hood at the latching point
after each closing. Check also for broken, damaged
or missing parts which might prevent secure latch-
ing.R. Fluid Leaks
- Check for fuel, water, oil or other
fluid leaks by observing the ground beneath the vehi-cle after it has been parked for a while. If gasoline
fumes or fluid are noticed at any time, the cause
should be determined and corrected without delay
because of the possibility of fire.
S. Exhaust System
- Be alert to any change in the
sound of the exhaust system or a smell of fumes
which may indicate a leak.
Head Restraints
- Check that no head restraint
components are missing, damaged or loose. (Does
not apply to GT Models).
Disc BrakesCheck brake pads and condition of rotors while
wheels are removed during tire rotation. (Note belowregarding more frequent checks also applies to disc
brakes.)
Parking and Drum BrakesCheck drum
brake linings and other internal brake
components at each wheel (drums, wheel cylinders,
etc.). Parking brake adjustment also should be
checked whenever drum brake linings are checked.
NOTE: More frequent checks should be
made if driving conditions a.nd habits result
in frequent brake application. When brakes
require relining, it is recommended thatyou use those genuine General Motors
parts specified for your car,and Delco fluid
as required.

lA- 21973 OPEL SERVICE MANUAL
BATER~ AND CABLES
ALL/ MODELS
C+NTENTIiSubject
DESCRIPTION AND OPERATION:
GeneralBatteryInformation
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .DIAGNOSIS:
Battery and Cables
- Trouble Diagno:sis. . . . . . . . . . . . . . . . . . . .MAINTENANCE AND ADJUSTMENTS:
PeriodicBatteryInspectionandService. . . . . . . . . . . . . . . . . . . .421BatteryTest
. . . . . . . . . . . . ...! . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Hydrometer Test of Batteiy
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
FusibleLinks. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .BatteryRecharging
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .MAJOR REPAIR:
Battery
RemovalandInstallation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
FusibleLinksRemovalandInstallation. . . . . . . . . . . . . . . . . . . . . .SPECIFICATIONS:
BatterySpecifications
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Page No.
1 A-2
1 A-4
1 A-5
1 A-6
1 A-7lA-8
1 A-9
1 A-9
1 A-9
1 A-9
DESCRIPTION AND OPERATIONGENERAL BATTERY INFORMATION
Registration of BatteryUnited-Delco Battery dealers and distributors
$reprepared to carry out terms of the manufacturer’s
warranty on Delco-General batteries. In order that
Opel owners shall have the protection and benefit of
this warranty, it is necessary for the dealer or car
owner to register his battery with the local United-
Delco Battery dealer or distributor on all new car
deliveries, and on all deliveries of new replacement
Delco batteries. The Battery Owner’s Certificate is
located in the Owner’s Protection Plan Booklet..
Care of Wet Batteries in StorageBatteries in stored new cars, as well as batteries, in
stock, must be given regular attention to prevent
sulphation of plates that may result from inactivity
and self-discharge. All automotive wet batteries will
slowly discharge on standing idle, whether in stored
vehicles or in stock, and will self-discharge muchfaster when warm than when cold.
Batteriesin stock
should be rotated and the oIder ones used tirst.To minimize the extent of self-discharge always store
batteries fully charged and in a cool place where the
temperature does not go below freezing. Every 30
days check the level of electrolyte, add water as re-
quired and charge the batteries at a 5 ampere rate
until fully charged.
Batteries used for display purposes or standing in
cars in storage must be treated in the same manner
as batteries in stock.
When a new car, or a new replacement battery is
delivered, make certain that it is
fuIly charged and
the electrolyte is at
proper level.This is extremely
important because the delivery of a partially dis-
charged battery may not only lead to its return for
charging but may also result in shortened life of
battery.
Importance of Maintaining Electrolyte at PROPER
LevelWater is the only component of the battery which is

BATTERY AND CABLES - ALL MODELSlA- 3
lost as the result of charging and discharging, and it
must be replaced before the electrolyte level falls to
the tops:of the separators. If the water is not replacedand the plates become exposed, they may become
permanently sulphated, which would impair the
per-forma”& of the plates. Also, the plates cannot take
full
par! in the battery action unless they are com-
pletely covered by the electrolyte.
Importance of Keeping Battery Properly Charged
The battery has three major functions: (1) It provides
a source of energy for cranking the engine. (2) It actsas a stabilizer to the voltage in the electrical system.
(3) It
c+n for a limited time furnish energy when the
demand: of the electrical units in operation exceed
the output of the generator.
In
ordei for the battery to continue to function, it is
necessaiy that current withdrawal from the battery
be balanced by current input from the generator so
that the battery is maintained in a properly chargedconditidn. If the outgo exceeds the input, the battery
will be&me discharged so that it cannot.supply suffi-cient energy.
The state of charge of the battery as well as the
temperature of the electrolyte has an important bear-ing on its capacity for supplying energy. Battery effi-
ciency is greatly reduced by decreased electrolyte
temper&e as it has a decided numbing effect on its
electrodhemical action. Under high discharge such
as cranking, battery voltage drops to lower values incold temperatures than in warm temperatures.
In
extrkmely cold climates it is important to keepbatter& in a nearly full charged condition to avoid
the possibility of freezing, which will damage any
battery!
The following table shows the temperatures at whichfreezing will occur in electrolytes of
differennt densi-
ties, wifh specific gravity corrected to 80 degrees l?
Specific Gravity Freezing Point
1.220 -35 degrees F.
1.200
-35 degrees F.
1.160
d degrees F.
Care of Dry Batteries in StorageA “dry charge” battery contains fully charged posi-
tive
a$ negative plates but no electrolyte.
Dry charged batteries should be stored in a dry placeaway from excessive heat. A dry charged battery
should
p kept in its original carton until ready to beput into service. This type of battery will retain its
“charged” condition indefinitely if protected from
moisture. Dry batteries may be stacked in vertical
columns provided they are not stacked more than
four high.
Preparing Dry Charged Batteries For ServiceTo prepare “dry charge” batteries for service use
approved battery-grade acid electrolyte (1.265 sp. gr.
at 80 degrees F). Care should be exercised in its useto prevent bodily injury or damage to clothing or
other material resulting from actual contact with the
electrolyte.
Electrolyte should be added to dry charged batteriesin an area where water is readily available for flush-
ing in case the electrolyte comes into contact with the
body. Refer to instructions on side of electrolyte con-tainer for antidotes to use if electrolyte comes into
contact with the body.
It is strongly recommended that a person filling bat-
teries with electrolyte wear glasses (preferably safetyglasses) to prevent possible damage to the eyes
should any spattering of the electrolyte occur.
1, Remove dry charged battery from its original car-
ton.2. Remove the vent plugs.
3. Using a glass or acid-proof plastic funnel, till eachbattery cell with electrolyte. Do not use a metal
funnel for filling the battery. The cell is properlytilled when the electrolyte level rises to the split ring
at the bottom of the vent well. Do not overfill orundertill. Overfilling will cause acid corrosion in the
,battery area; undertilling will cause early battery fail-
UR.4. After tilling cells, wait five to ten minutes and add
additional electrolyte, if necessary, to bring the elec-
trolyte to the proper level.
5. Never finish tilling a dry charge battery with wa-
ter. If electrolyte is spilled, more electrolyte must be
obtained.
Test After Batteries
ere Prepared For ServiceThe Delco Dry Charge Battery may be put into ser-
vice immediately after activation. However, to insuregood battery performance, the following activation
tests are recommended:1. After adding electrolyte,, check the open circuit
voltage. Less than 10 volts mdicates a reverse cell oran open circuit and the battery should be replaced.
2. Check the specific gravity of all cells. If the specific

BATTERY AND CABLES - ALL MODELSlA- 5
and terminal connections should not exceed 2/10
volt.
5. Connedt voltmeter positive lead to ground on en-
gine.
At&h prod to voltmeter negative lead and
apply prod to center of battery negative post. Volt-
age drop across the battery ground cable and termi-
nal conne$tions should not exceed 2/10 volt at
200amps.
6. A reading in excess of 2/10 volt when testing
either battery cable indicates excessive resistance in
cable or cpnnections. Clean and tighten cable or con-
nections. Clean and tighten cable terminals
(sub-para. c, below) and recheck for voltage drop. If volt-
age drop Still exceeds 2/10 volt, replace cable with a
genuine Buick-Opel cable to insure ample capacity.
Undercharge Failure of BatteryThe most frequent trouble experienced with storage
batteries is failure to maintain a state of charge suffi-
cient to crank the engine and also furnish current to
the ignitibn system, lights and accessories. Failure to
maintain a proper state of charge may be due to one
or more of the following conditions:
1.
Opertiting Conditions. When determining cause
of premature failure of a battery, consideration must
be given /to the conditions under which the car is
operated.,
In very low temperatures the capacity of a storage
battery
ii considerably reduced and the energy re-
quired f& cranking the. engine is considerably in-
creased. :
Frequent starting, particularly in cold weather,
ac-compani the batteqy for cranking than the generator can re-
place in the limited running time. This condition is
aggravated by night driving when lights are turned
on, or by operation of an air conditioner in heavy
traffic.
When thk car is operated under these conditions,adjusting,the voltage regulator to the high limit may
allow enough increase to keep the battery at a safe
state of charge. If the high limit setting does not
maintain a safe state of charge, an occasional booster
charge should be given to the battery.
2. Low charging Rate. In case of premature battery
failure, tbe charging rate of alternator should always
be checked and adjusted if below specifications.
3.
Zntemd Condition The internal condition of the
battery niay be such that it cannot hold a chargesatisfactoiily. Check electrolyte level and test the
battery using the 421 Battery Test.
Overcharge Failure of BatteryA common cause of battery failure is overcharging,
that is, continued input of excessive charging current
after the battery has reached a fully charged condi-
tion.
One evidence that battery is being overcharged is the
need for frequent addition of water to the battery in
order to maintain the electrolyte level above the tops
of the battery separators, since overcharging causes
rapid water loss. When this becomes evident, the
charging rate of alternator should be immediately
checked, as well as the voltage regulator, and ad-
justed to avoid internal damage to battery.
ADJUSTMENTS AND MINOR SERVICEPERIODIC BATTERY INSPECTION AND SERVICE
The battery requires very little attention, but peri-
odic inspection is essential to secure the maximum
efficiency and life. The following services are essen-
tial to maintain the battery at maximum efficiency.
WARNING: Never expose battery to open flame or
electric spark
- battery action generates hydrogen gas
which is flammable and explosive. Do not allow bat-
tery fluid to contact skin, eyes, fabrics or painted
surfaces
- fluidis a sulfuric acid solution which could
cause serious personal injury or property damage.
Wear eye protection when working with battery.
Maintain Electrolyte LevelAdd distilled water as required to maintain the elec-
trolyte level at the split ring at bottom of tiller well.
See Figure IA-2.
Figure lA-2
Battery Filler Well

j
/lA- 61973 OPEL SERVICE MANUAL
Do not overfill, as electrolyte may
be sprayed out by
gassing or may overtlow due to heat expansion dur:
ing charging.
If distilled water is not available, it is better to add
clean, mineral-free tap water than to allow the
elec2trolyte level to remain below the top of the plates:
In freezing weather the water should be added just
before using the car or otherwise charging the bat-
tery so that the water will be mixed with the acid
before it is allowed to stand in freezing temperatures.
If it is found necessary to add water to the
batterimore frequently than about every
1,ooO miles and the
quantity of water added per cell is’ excessive, check
setting of voltage regulator and adjust, if necessary:
Abnormal water loss is an indication that the battery
is being overcharged.
Inspect Battery, Mounting and Cables
Check outside of battery for damage or signs of se&ous abuse such as broken case or broken covers:
Check inside of battery by removing the vent caps
and inspecting for signs of abuse
stich as electrolyte
level too low to see, or bad or unusual odors. If
battery shows signs of serious damage or abuse, it
should be replaced.
Check the battery hold down bolts to make certain
that battery is securely held in place. The nut should
be drawn up to 20 lbs. in.;excessjve tightening may
distort or crack the battery case.If the top of battery is dirty or the hold down str?e
is corroded, clean thoroughly with a brush dipped
IFammonia or soda solution. Care must be used td
prevent any solution from getting into battery
cellslAfter the foaming of solution stops, flush off witli
clean water and dry thoroughly. If hold down strap
is corroded it should be painted with acid-resisting
paint after cleaning.
Check battery cables to make certain they are tight
at bracket and junction block. If a connection is
found loose it should be cleaned before being tight;ened as arcing and corrosion may have taken place
in the loose connection. Check condition of cables
and replace if badly corroded or frayed.
Special attention must be given to,the battery posi-
tive cable position to eliminate the possibility of con-
tact with the exhaust manifold on the 1.1 liter engine.
The cable clamp must be rotated clockwise as neces-
sary for the cable to run at a 45 degree angle toward
the right wheelhouse panel.
Cleaning Cable Terminals
If loose connections are found by inspection, or highresistance is found by voltage test, disconnect the
cable for thorough cleaning of terminals. When
removing a corroded cable terminal from battery
post, do not pry against battery case or hammer on
terminal to break it loose, since either practice will
result in broken cell covers. Use a screw-type termi-
nal puller if terminal cannot be loosened by hand.
Thoroughly clean all corrosion from disconnected
battery cable terminals and terminal posts, using
suitable wire brushes. If wire brushes are not availa-
ble, corroded terminals may be cleaned by brushing
with a strong soda solution, using care not to get
solution into battery cells.
If
cabbz strands are broken, corroded, or loose in
terminals, the cable should be replaced with the cor-
rect cable to insure ample capacity.
To prevent corrosion of battery terminals and con-
nections, apply a coating of petroleum jelly over the
battery post and cable terminals after cables have
been installed on terminals.
421 BATTERY TEST421 Battery Testers, manufactured and sold by a
number of companies, are the only battery testers
approved by Delco-Remy Division for testing one-
piece cover batteries. They are also used by United
Motors Service to determine whether or not a battery
is defective.
Figure lA-3 421 Battery Tester-Charger
The
42,l Battery Tester shows, in a few minutes, the
state-of-charge of the battery and whether it is good
or bad. The tester can be used with any 12 volt
battery, in or out of the car. The test can be made
regardless of the state of charge of the battery; it can
also be made when the electrolyte level is low
- even
below the top of the plates.

BATTERY AND CABLES - ALL MODELSlA- 7
421 Test
F$ocedure1. Visual Inspection
- The first step in testing the
Energizer br 12-V& Battery should be a visual in-
spection
which very often will save time, labor and
expense in determining the condition.
(a) Check for broken or cracked case or cover.
(b) Check ,for loose terminal posts.
fiozeck Ifor defective or mutilated sealing com-(d) Check for other visible signs of physical damage.
Obvious d?mage as a result of conditions described
above indicates the need for Energizer or batteryreplaceme$t.
2. The “421” Test is a programmed test procedure
consisting bf a series of timed discharge and charge
events, reqtdring approximately 2 to 3 minutes, that
will determine the condition of the Energizer or bat-
tery with a high degree of accuracy when used inconjunctioti with this entire test procedure. “421”
Testers
a$ produced by a number of different manu-
facturers
r+nd their directions for tester operation
should be carefully followed. General comments on
overall “42 1” Tester operation follow:
(a) Energi@rs or batteries should
nor be charged
prior to
making this test. Defects within the unit can
be hidden by the charging and erroneous test results
will be obtpined.
(b) Erratic, or extremely low, initial meter readings
may indicate poor connections at the tester termi-
nals.Obt{in clean and tight connections beforeper-
forming the 421
Test.(c) All meter readings should be made immediately
after the meter indicator light comes on even if the
meter needle is still moving.
(d) If additional discharges are required after the
initial discbarge, set meter indicator following thefast discharge cycle.
(e) Batteries designated as “bad” by the tester should
be replaced.
(f) Batteries designated as “good” with no owner’s
complaint or indication of poor performance, should
be left in s+vice. Posts, cable clamps, and top should
be cleaned, water should be added and recharging
should be
,performed, if required. For dependable
and reliable battery service, the battery should be in
at least a
75 per cent state-of-charge.
(g) Batteries designated as “good” that are suspected
of being questionable because of owner complaint, orage of the battery, should be further tested by the
Hydrometer Test.
HYDROMETER TEST OF BATTERY
The 421 Battery Test as described in the previous
paragraph is the fastest and most accurate means of
determining the serviceability of a one-piece cover
battery. However, ifa 421 Battery Tester is not avail-
able, a hydrometer test may be used on a battery that
has failed to give proper service.
Hydrometer Test1. Fully charge battery.
2. Measure specific gravity of each cell as described
in sub-paragraph below.
Decide battery serviceability as follows:
(a) If all cells read between 1.230 and 1.310, the
battery is okay. All it needed was a full charge.
(b) After fully charging battery, if any cell reads less
than 1.230, the battery is defective and should be
replaced.
Use of HydrometerThe Hydrometer measures the percentage of sulphu-
ric acid in the battery electrolyte in terms of specific
gravity. As a battery drops from a charged to a dis-
charged condition, the acid leaves the solution and
enters the plates, causing a decrease in specific
gravity of electrolyte. With a hydrometer, an indica-
tion of the concentration of the electrolyte is ob-
tained.
The specific gravity of the electrolyte varies not only
with the percentage of acid in the liquid, it also varies
with temperature. As temperature increases, the
electrolyte expands so that the specific gravity is re-
duced. As temperature drops, the electrolyte con-
tracts so that the specific gravity increases. Unless
these variations in specific gravity are taken into
account, the specific gravity obtained by the hy-
drometer may not give a true indication of the con-
centration of acid in the electrolyte.
Correction can be made for temperature by adding
,004, usually referred to as 4 “points of gravity”, to
the hydrometer reading for every 10 degrees F. that
the electrolyte is above 80 degrees F. or subtracting004 for every 10 degrees F. that electrolyte is below
80 degrees F. Figure IA-4 shows the exact correctionfigure to use for any temperature above or below 80
degrees F., the three steps used in obtaining the cor-
rected or true specific gravity, and two examples
showing how it is figured.