
TROUBLESHOOTlNGll-11
b. Driveshaft misaligned. Check for collapsed or damaged engine and transmission
mounts, and replace as necessary.
c. Driveshaft bent or out of balance. Replace damaged components and reinstall.
d. Driveshaft out of balance. Remove the driveshaft and have it balanced by a competent
professional, or replace the driveshaft assembly.
NOTE: Most driveshafts are linked together by universal joints; however,
some manufacturers use Constant Velocity (CV) joints or rubber flex cou-
plers.
All Wheel and Four Wheel Drive Vehicles
1. Front or rear wheel makes a clicking noise
a. Check for debris such as a pebble, nail or glass in the tire or tire tread. Carefully re-
move the debris. Small rocks and pebbles rarely cause a puncture; however, a sharp
object should be removed carefully at a facility capable of performing tire repairs.
b. Check for a loose, damaged or worn Constant Velocity (CV) joint and replace if defec-
tive.
2. Front or rear wheel vibrates wlth Increased speed
a. Check for a bent rim and replace, if damaged.
b. Check the tires for balance or internal damage and replace if defective.
c. Check for a loose, worn or damaged wheel bearing and replace if defective.
d. Check for a loose, damaged or worn Constant Velocity (CV) joint and replace if defec-
tive.
Front Wheel Drive Vehicles
3. Front wheel makes a c&kin@ noise
a. Check for debris such as a pebble, nail or glass in the tire or tire tread. Carefully re-
move the debris. Small rocks and pebbles rarely cause a puncture; however, a sharp
object should be removed carefully at a facility capable of performing tire repairs.
b. Check for a loose, damaged or worn Constant Velocity (CV) joint and replace if defec-
tive. 4. Rear wheel makes a clicking noise
a. Check for debris such as a pebble, nail or glass in the tire or tire tread. Carefully re-
move the debris. Small rocks and pebbles rarely cause a puncture; however, a sharp
object should be removed carefully at a facility capable of performing tire repairs.
Rear Wheel Drive Vehicles
5. Front or rear wheel makes a clicking noise
a. Check for debris such as a pebble, nail or glass in the tire or tire tread. Carefully re-
move the debris. Small rocks and pebbles rarely cause a puncture; however, a sharp
object should be removed carefully at a facility capable of performing tire repairs.
6. Rear wheel shudders or vibrates
a. Check for a bent rear wheel or axle assembly and replace defective components.
b. Check for a loose, damaged or worn rear wheel bearing and replace as necessary.
1. Burning odor from center of vehicle when accelerating
a. Check for a seizing brake hydraulic component such as a brake caliper. Check the
caliper piston for surface damage such as rust, and measure for out-of-round wear
and caliper-to-piston clearance. For additional information on brake related odors, re-
fer to section 3-A, condition number 9.
b. On vehicles with a manual transmission, check for a slipping clutch. For possible
causes and additional information, refer to section Z-C, condition number 1.
c. On vehicles with an automatic transmission, check the fluid level and condition, Top
off or change the fluid and filter using the recommended replacement parts, lubricant
type and amount. If the odor persists, transmission removal and disassembly will be
necessary.
2. Engine accelerates, but vehicle does not gain speed
a. On vehicles with a manual transmission, check for a slipping or damaged clutch. For
possible causes and additional information refer to section Z-C, condition number 1.
b. On vehicles with an automatic transmission, check the fluid level and condition. Top
off or change the fluid and filter using the recommended replacement parts, lubricant
type and amount. If the slipping continues, transmission removal and disassembly will
be necessary.
1. Brake pedal pulsates or shimmies when pressed
a. Check wheel lug nut torque and tighten evenly to specification.
b. Check the brake rotor for trueness and thickness variations. Replace the rotor if it is
too thin, warped, or if the thickness varies beyond specification. Some rotors can be
machined: consult the manufacturer’s specifications and recommendations before us-
ing a machined brake rotor.
c. Check the brake caliper or caliper bracket mounting bolt torque and inspect for loose-
ness. Torque the mounting bolts and inspect for wear or any looseness, including
worn mounting brackets, bushings and sliding pins.
d. Check the wheel bearing for looseness. If the bearing is loose, adjust if possible, oth-
erwise replace the bearing.
2. Brakes make a squealing noise
a. Check the brake rotor for the presence of a ridge on the outer edge; if present, remove
the ridge or replace the brake rotor and brake pads.
b. Check for debris in the brake lining material, clean and reinstall.
c. Check the brake linings for wear and replace the brake linings if wear is approaching
the lining wear limit.
d. Check the brake linings for glazing. Inspect the brake drum or rotor surface and re-
place, along with the brake linings, if the surface is not smooth or even.
e. Check the brake pad or shoe mounting areas for a lack of lubricant or the presence of
surface rust. Clean and lubricate with a recommended high temperature brake grease.
3. Brakes make a flrindinfl noise
a. Check the brake linings and brake surface areas for severe wear or damage. Replace
worn or damaged parts.
b. Check for a seized or partially seized brake causing premature or uneven brake wear,
excessive heat and brake rotor or drum damage. Replace defective parts and inspect
the wheel bearing condition, which could have been damaged due to excessive heat.
4. Vehicle pulls to one side during braking
a. Check for air in the brake hydraulic system. Inspect the brake hydraulic seals, fluid
lines and related components for fluid leaks. Remove the air from the brake system by bleeding the brakes. Be sure to use fresh brake fluid that meets the manufacturers rec-
ommended standards.
b. Check for an internally restricted flexible brake hydraulic hose. Replace the hose and
flush the brake system.
c. Check for a seizing brake hydraulic component such as a brake caliper. Check the
caliper piston for surface damage such as rust, and measure for out-of-round wear
and caliper-to-piston clearance. Overhaul or replace failed parts and flush the brake
system.
d. Check the vehicle’s alignment and inspect for suspension wear. Replace worn bush-
ings, ball joints and set alignment to the manufacturers specifications.
e. If the brake system uses drum brakes front or rear, check the brake adjustment. Inspect
for seized adjusters and clean or replace, then properly adjust.
5. Brake pedal feels spongy or has excessive travel
a. Check the brake fluid level and condition. If the fluid is contaminated or has not been
flushed every two years, clean the master cylinder reservoir, and bleed and flush the
brakes using fresh brake fluid that meets the manufacturers recommended standards.
b. Check for a weak or damaged flexible brake hydraulic hose. Replace the hose and
flush the brake system.
c. If the brake system uses drum brakes front or rear, check the brake adjustment. Inspect
for seized adjusters and clean or replace, then properly adjust.
6. Brake pedal feel is firm, but brakes lack sufficient stopping power or
fade
a. Check the operation of the brake booster and brake booster check valve: Replace worn
or failed parts.
b. Check brake linings and brake surface areas for glazing and replace worn or damaged
parts.
c. Check for seized hydraulic parts and linkages, and clean or replace as needed.
7. Vehicle has excessive front end dive or locks rear brakes too easily
a. Check for worn, failed or seized brake proportioning valve and replace the valve.
b. Check for a seized, disconnected or missing spring or linkage for the brake propor-
tioning valve. Replace missing parts or repair as necessary.

GLOSSARY 1149
GENERATOR: A device which produces direct current (DC) necessary to
charge the battery. OVERHEAD CAMSHAFT (OHC): An engine configuration in which the
camshaft is mounted on top of the cylinder head and operates the valve either
directly or by means of rocker arms.
HEAT RANGE: A term used to describe the ability of a spark plug to carry
away heat. Plugs with longer nosed insulators take longer to carry heat off
effectively.
HUB: The center part of a wheel or gear.
HYDROCARBON (HC): Any chemical compound made up of hydrogen
and carbon. A major pollutant formed by the engine as a by-product of
combustion.
HYDROMETER: An instrument used to measure the specific gravity of a so-
lution.
INCH POUND (inch Ibs.; sometimes in. lb. or in. Ibs.): One twelfth
.
of a foot pound.
INDUCTION: A means of transferring electrical energy in the form of a mag-
netic field. Principle used in the ignition coil to increase voltage.
INJECTOR: A device which receives metered fuel under relatively low pres-
sure and is activated to inject the fuel into the engine under relatively high
pressure at a predetermined time.
INPUT SHAFT: The shaft to which torque is applied, usually carrying the dri-
ving gear or gears.
INTAKE MANIFOLD: A casting of passages or pipes used to conduct air or
a fuel/air mixture to the cylinders.
JOURNAL: The bearing surface within which a shaft operates.
KEY: A small block usually fitted in a notch between a shaft and a hub to pre-
vent slippage of the two parts.
MANIFOLD: A casting of passages or set of pipes which connect the cylin-
ders to an inlet or outlet source.
MASTER CYLINDER: The primary fluid pressurizing device in a hydraulic
system. In automotive use, it is found in brake and hydraulic clutch systems
and is pedal activated, either directly or, in a power brake system, through the
power booster.
MODULE: Electronic control unit, amplifier or igniter of solid state or inte-
grated design which controls the current flow in the ignition primary circuit
based on input from the pick-up coil. When the module opens the primary cir-
cuit, high secondary voltage is induced in the coil.
NEEDLE BEARING: A bearing which consists of a number (usually a large
number) of long, thin rollers.
OHM: The unit used to measure the resistance of conductor-to-electrical flow.
One ohm is the amount of resistance that limits current flow to one ampere in
a circuit with one volt of pressure.
OHMMETER: An instrument used for measuring the resistance, in ohms, in
an electrical circuit.
OUTPUT SHAFT: The shaft which transmits torque from a device, such as a
transmission. OVERHEAD VALVE (OHV): An engine configuration in which all of the
valves are located in the cylinder head
and the camshaft is located in the cylin-
der block. The camshaft operates the valves via lifters and pushrods.
OXIDES OF NITROGEN (NOx): Chemical compounds of nitrogen produced
as a byproduct of combustion. They combine with hydrocarbons to produce
smog.
OXYGEN SENSOR: Used with a feedback system to sense the presence of
oxygen in the exhaust gas and signal the computer which can use the voltage
signal to determine engine operating efficiency and adjust the air/fuel ratio.
PINION: The smaller of two gears. The rear axle pinion drives the ring gear
which transmits motion to the axle shafts.
PISTON RING: An open-ended ring which fits into a groove on the outer di-
ameter of the piston. Its chief function is to form a seal between the piston and
cylinder wall. Most automotive pistons have three rings: two for compression
sealing; one for oil sealing.
PRELOAD: A predetermined load placed on a bearing during assembly or by
adjustment.
PRESS FIT: The mating of two parts under pressure, due to the inner diam-
eter of one being smaller than the outer diameter of the other, or vice versa;
an interference fit.
PRIMARY CIRCUIT: The low voltage side of the ignition system which con-
sists of the ignition switch, ballast resistor or resistance wire, bypass, coil,
electronic control unit and pick-up coil as well as the connecting wires and
harnesses.
RACE: The surface on the inner or otiter ring of a bearing on which the balls,
needles or rollers move.
REGULATOR: A device which maintains the amperage and/or voltage levels
of a circuit at predetermined values.
RELAY: A switch which automatically opens and/or closes a circuit.
RESISTANCE: The opposition to the flow of current through a circuit or elec-
trical device, and is measured in ohms. Resistance is equal to the voltage di-
vided by the amperage.
RESISTOR: A device, usually made of wire, which offers a preset amount of
resistance in an electrical circuit.
RING GEAR: The name given to a ring-shaped gear attached to a differential
case, or affixed to a flywheel or as part of a planetary gear set.
ROLLER BEARING: A bearing made up of hardened inner and outer races
between which hardened steel rollers move.
ROTOR: (1.) The disc-shaped part of a disc brake assembly, upon which the
brake pads bear; also called, brake disc. (2.) The device mounted atop the dis-
tributor shaft, which passes current to the distributor cap tower contacts.

II-20 GLOSSARY
SECONDARY CIRCUIT: The high voltage side of the ignition system, usu-
ally above 20,000 volts. The secondary includes the ignition coil, coil wire,
distributor cap and rotor, spark plug wires and spark plugs.
SENDING UNIT: A mechanical, electrical, hydraulic or electromagnetic de-
vice which transmits information to a gauge.
SENSOR: Any device designed to measure engine operating conditions or
ambient pressures and temperatures. Usually electronic in nature and designed
to send a voltage signal to an on-board computer, some sensors may oper-
ate as a simple on/off switch or they may provide a variable voltage signal
(like a potentiometer) as conditions or measured parameters change.
SHIM: Spacers of precise, predetermined thickness used between parts to es-
tablish a proper working relationship.
SLAVE CYLINDER: In automotive use, a device in the hydraulic clutch sys-
tem which is activated by hydraulic force, disengaging the clutch.
SOLENOID: An electrically operated, magnetic switching device.
SPARK PLUG: A device screwed into the combustion chamber of a spark ig-
nition engine. The basic construction is a conductive core inside of a ceramic
insulator, mounted in an outer conductive base. An electrical charge from the
spark plug wire travels along the conductive core and jumps a preset air gap
to a grounding point or points at the end of the conductive base. The resul-
tant spark ignites the fuel/air mixture in the combustion chamber.
SPLINES: Ridges machined or cast onto the outer diameter of a shaft or in-
ner diameter of a bore to enable parts to mate without rotation.
TACHOMETER: A device used to measure the rotary speed of an engine,
shaft, gear, etc., usually in rotations per minute.
THERMOSTAT: A valve, located in the cooling system of an engine, which
is closed when cold and opens gradually in response to engine heating, con-
trolling the temperature of the coolant and rate of coolant flow.
TOP DEAD CENTER (TDC): The point at which the piston reaches the top
of its travel on the compression stroke.
TORQUE: Measurement of turning or twisting force, expressed as foot-pounds
or inch-pounds.
TORQUE CONVERTER: A turbine used to transmit power from a driving
member to a driven member via hydraulic action, providing changes in drive
ratio and torque. In automotive use, it links the driveplate at the rear of the en-
gine to the automatic transmission. TRANSDUCER: A device that changes energy from one form to another. For
example, a transducer in a microphone changes sound energy to electrical en-
ergy. In automotive air-conditioning controls used in automatic temperature
systems, a transducer changes an electrical signal to a vacuum signal, which
operates mechanical doors.
TRANSISTOR: A semi-conductor component which can be actuated by a
small voltage to perform an electrical switching function.
TUNE-UP: A regular maintenance function, usually associated with the re-
placement and adjustment of parts and components in the electrical and fuel
systems of a vehicle for the purpose of attaining optimum performance.
TURBOCHARGER: An exhaust driven pump which compresses intake air
and forces it into the combustion chambers at higher than atmospheric pres-
sures The increased air pressure allows more fuel to be burned and results
in increased horsepower being produced.
.
VACUUM ADVANCE: A device which advances the ignition timing in re-
sponse to increased engine vacuum.
VACUUM GAUGE: An instrument used for measuring the existing vacuum
in a vacuum circuit or chamber. The unit of measure is inches (of mercury in
a barometer).
VALVE: Devices that can open or close fluid passages in a hydraulic system
and are used for directing fluid flow and controlling pressure.
VALVE CLEARANCE: The measured gap between the end of the valve stem
and the rocker arm, cam lobe or follower that activates the valve.
VISCOSITY: The ability of a fluid to flow. The lower the viscosity rating, the
easier the fluid will flow. 10 weight motor oil will flow much easier than 40
weight motor oil.
VOLTMETER: An instrument used for measuring electrical force in units
called volts. Voltmeters are always connected parallel with the circuit being
tested.
WHEEL CYLINDER: Found in the automotive drum brake assembly, it is a
device, actuated by hydraulic pressure, which, through internal pistons, pushes
the brake shoes outward against the drums.