weight DODGE RAM 2002 Service Service Manual

exerted is downward (gravity), however, the principle
remains the same no matter which direction is taken.
The pressure created in the fluid is equal to the force
applied, divided by the piston area. If the force is 100
lbs., and the piston area is 10 sq. in., then the pres-
sure created equals 10 PSI. Another interpretation of
Pascal's Law is that regardless of container shape or
size, the pressure will be maintained throughout, as
long as the fluid is confined. In other words, the
pressure in the fluid is the same everywhere within
the container.
FORCE MULTIPLICATION
Using the 10 PSI example used in the illustration
(Fig. 191), a force of 1000 lbs. can be moved with a
force of only 100 lbs. The secret of force multiplica-
tion in hydraulic systems is the total fluid contact
area employed. The illustration, (Fig. 191), shows an
area that is ten times larger than the original area.
The pressure created with the smaller 100 lb. input
is 10 PSI. The concept ªpressure is the same every-
whereº means that the pressure underneath the
larger piston is also 10 PSI. Pressure is equal to the
force applied divided by the contact area. Therefore,
by means of simple algebra, the output force may be
found. This concept is extremely important, as it is
also used in the design and operation of all shift
valves and limiting valves in the valve body, as well
as the pistons, of the transmission, which activate
the clutches and bands. It is nothing more than
using a difference of area to create a difference in
pressure to move an object.
PISTON TRAVEL
The relationship between hydraulic lever and a
mechanical lever is the same. With a mechanical
lever it's a weight-to-distance output rather than a
pressure-to-area output. Using the same forces and
areas as in the previous example, the smaller piston
(Fig. 192) has to move ten times the distance
required to move the larger piston one inch. There-
fore, for every inch the larger piston moves, the
smaller piston moves ten inches. This principle is
true in other instances also. A common garage floor
jack is a good example. To raise a car weighing 2000
lbs., an effort of only 100 lbs. may be required. For
every inch the car moves upward, the input piston at
the jack handle must move 20 inches downward.
Fig. 189 Force and Pressure Relationship
Fig. 190 Pressure on a Confined Fluid
Fig. 191 Force Multiplication
21 - 368 AUTOMATIC TRANSMISSION - 47REBR/BE
PISTONS (Continued)

from second high spot to first. Break down the tire
and remount it 90 degrees on rim in that direction
(Fig. 8). This procedure will normally reduce the
runout to an acceptable amount, if not replace the
rim.STANDARD PROCEDURE - TIRE AND WHEEL
BALANCE
It is recommended that a two plane service
dynamic balancer be used when a tire and wheel
assembly require balancing. Refer to balancer opera-
tion instructions for proper cone mounting proce-
dures. Typically use front cone mounting method for
steel wheels. For aluminum wheel use back cone
mounting method without cone spring.
NOTE: Static should be used only when a two plane
balancer is not available.
NOTE: Cast aluminum and forged aluminum wheels
require coated balance weights and special align-
ment equipment.
Wheel balancing can be accomplished with either
on or off vehicle equipment. When using on-vehicle
balancing equipment, remove the opposite wheel/tire.
Off-vehicle balancing is recommended.
For static balancing, find the location of the heavy
spot causing the imbalance. Counter balance wheel
directly opposite the heavy spot. Determine weight
required to counter balance the area of imbalance.
Place half of this weight on theinnerrim flange and
the other half on theouterrim flange (Fig. 9).
For dynamic balancing, the balancing equipment is
designed to locate the amount of weight to be applied
to both the inner and outer rim flange (Fig. 10).
Fig. 8 Remount Tire 90 Degrees In Direction of
Arrow
1 - 2ND HIGH SPOT ON TIRE
2 - 1ST HIGH SPOT ON TIRE
22 - 4 TIRES/WHEELSBR/BE
TIRES/WHEELS (Continued)

Fig. 9 Static Unbalance & Balance
1 - HEAVY SPOT
2 - CENTER LINE OF SPINDLE
3 - ADD BALANCE WEIGHTS HERE4 - CORRECTIVE WEIGHT LOCATION
5 - TIRE OR WHEEL TRAMP, OR WHEEL HOP
Fig. 10 Dynamic Unbalance & Balance
1 - CENTER LINE OF SPINDLE
2 - ADD BALANCE WEIGHTS HERE3 - CORRECTIVE WEIGHT LOCATION
4 - HEAVY SPOT WHEEL SHIMMY AND VIBRATION
BR/BETIRES/WHEELS 22 - 5
TIRES/WHEELS (Continued)

SPARE TIRE
DESCRIPTION
The temporary spare tire is designed for emer-
gency use only. The original tire should be repaired
or replaced at the first opportunity, then reinstalled.
Do not exceed speeds of 50 M.P.H. when using the
temporary spare tire. Refer to Owner's Manual for
complete details.
WHEELS
DESCRIPTION
Original equipment wheels are designed for the
specified Maximum Vehicle Capacity.
All models use steel or cast aluminum drop center
wheels.
Cast aluminum wheels require special balance
weights and alignment equipment.
Ram Truck Models equipped with dual rear wheels
have eight-stud hole rear wheels. The wheels have a
flat mounting surface (Fig. 17). The slots in the
wheel must be aligned to provide access to the valve
stem (Fig. 18).
OPERATION
The wheel (Fig. 19) has raised sections between
the rim flanges and the rim well. Initial inflation of
the tire forces the bead over these raised sections. In
case of tire failure, the raised sections hold the tire
in position on the wheel until the vehicle can be
brought to a safe stop.
Fig. 17 Flat Face Wheel
1 - FLAT FACE
Fig. 18 Dual Rear Wheels
1 - INBOARD WHEEL VALVE STEM
2 - OUTBOARD WHEEL VALVE STEM
Fig. 19 Safety Rim
1 - FLANGE
2 - RIDGE
3 - WELL
22 - 10 TIRES/WHEELSBR/BE

PLUMBING
TABLE OF CONTENTS
page page
PLUMBING
DESCRIPTION..........................40
OPERATION............................41
WARNING..............................42
CAUTION..............................42
DIAGNOSIS AND TESTING
DIAGNOSIS AND TESTING - REFRIGERANT
SYSTEM LEAKS.......................43
STANDARD PROCEDURE
STANDARD PROCEDURE - A/C LINE
COUPLERS...........................44
STANDARD PROCEDURE - REFRIGERANT
SYSTEM SERVICE EQUIPMENT...........45
STANDARD PROCEDURE - REFRIGERANT
RECOVERY...........................45
STANDARD PROCEDURE - REFRIGERANT
SYSTEM EVACUATE....................46
STANDARD PROCEDURE - REFRIGERANT
SYSTEM CHARGE......................46
SPECIFICATIONS........................46
A/C COMPRESSOR
DESCRIPTION..........................46
OPERATION............................46
DIAGNOSIS AND TESTING
DIAGNOSIS AND TESTING - A/C
COMPRESSOR........................47
REMOVAL..............................47
INSTALLATION..........................48
A/C CONDENSER
DESCRIPTION..........................49
OPERATION............................49
REMOVAL..............................49
INSTALLATION..........................50
SUCTION AND DISCHARGE LINE
REMOVAL..............................51
INSTALLATION..........................52LIQUID LINE
REMOVAL..............................52
INSTALLATION..........................52
A/C EVAPORATOR
DESCRIPTION..........................53
OPERATION............................53
REMOVAL..............................53
INSTALLATION..........................53
A/C ORIFICE TUBE
DESCRIPTION..........................54
OPERATION............................54
DIAGNOSIS AND TESTING
DIAGNOSIS AND TESTING - FIXED
ORIFICE TUBE.........................54
REMOVAL..............................54
INSTALLATION..........................54
ACCUMULATOR
DESCRIPTION..........................55
OPERATION............................55
REMOVAL..............................55
INSTALLATION..........................55
HEATER CORE
DESCRIPTION..........................56
OPERATION............................56
REMOVAL..............................56
INSTALLATION..........................56
REFRIGERANT
DESCRIPTION..........................56
OPERATION............................57
REFRIGERANT OIL
DESCRIPTION..........................57
OPERATION............................57
STANDARD PROCEDURE
STANDARD PROCEDURE - REFRIGERANT
OIL LEVEL............................57
PLUMBING
DESCRIPTION - A/C LINE COUPLERS
Spring-lock type refrigerant line couplers are used
to connect many of the refrigerant lines and other
components to the refrigerant system. These couplers
require a special tool for disengaging the two coupler
halves.
DESCRIPTION- REFRIGERANT LINES
The refrigerant lines and hoses are used to carry
the refrigerant between the various air conditioning
system components. A barrier hose design with a
nylon tube, which is sandwiched between rubber lay-
ers, is used for the R-134a air conditioning system on
this vehicle. This nylon tube helps to further contain
the R-134a refrigerant, which has a smaller molecu-
lar structure than R-12 refrigerant. The ends of the
refrigerant hoses are made from lightweight alumi-
num or steel, and commonly use braze-less fittings.
24 - 40 PLUMBINGBR/BE