Ford Explorer, Maintaince And Repair Manual, Page: 68 / 1119

CAUTION
Battery electrolyte contains sulfuric acid. If you should splash any on your skin or in your eyes, flush the
affected area with plenty of clear water. If it lands in your eyes, get medical help immediately.
The fluid (sulfuric acid solution) contained in the battery cells will tell you many things about the condition of
the battery. Because the cell plates must be kept submerged below the fluid level in order to operate, the fluid
level is extremely important. And, because the specific gravity of the acid is an indication of electrical charge,
testing the fluid can be an aid in determining if the battery must be replaced. A battery in a vehicle with a
properly operating charging system should require little maintenance, but careful, periodic inspection should
reveal problems before they leave you stranded.
At least once a year, check the specific gravity of the battery. It should be between 1.20 and 1.26 on the
gravity scale. Most auto stores carry a variety of inexpensive battery hydrometers. These can be used on any
non−sealed battery to test the specific gravity in each cell.
The battery testing hydrometer has a squeeze bulb at one end and a nozzle at the other. Battery electrolyte is
sucked into the hydrometer until the float is lifted from its seat. The specific gravity is then read by noting the
position of the float. If gravity is low in one or more cells, the battery should be slowly charged and checked
again to see if the gravity has come up. Generally, if after charging, the specific gravity between any two cells
varies more than 50 points (0.50), the battery should be replaced, as it can no longer produce sufficient
voltage to guarantee proper operation.
CABLES
Once a year (or as necessary), the battery terminals and the cable clamps should be cleaned. Loosen the
clamps and remove the cables, negative cable first. On top post batteries, the use of a puller specially made for
this purpose is recommended. These are inexpensive and available in most parts stores. Side terminal battery
cables are secured with a small bolt.
Clean the cable clamps and the battery terminal with a wire brush, until all corrosion, grease, etc., is removed
and the metal is shiny. It is especially important to clean the inside of the clamp thoroughly (an old knife is
useful here), since a small deposit of oxidation there will prevent a sound connection and inhibit starting or
charging. Special tools are available for cleaning these parts, one type for conventional top post batteries and
another type for side terminal batteries. It is also a good idea to apply some dielectric grease to the terminal, as
this will aid in the prevention of corrosion.
After the clamps and terminals are clean, reinstall the cables, negative cable last; DO NOT hammer the
clamps onto battery posts. Tighten the clamps securely, but do not distort them. Give the clamps and terminals
a thin external coating of grease after installation, to retard corrosion.
Check the cables at the same time that the terminals are cleaned. If the cable insulation is cracked or broken,
or if the ends are frayed, the cable should be replaced with a new cable of the same length and gauge.
HOW TO USE THIS BOOK
54 CABLES