1990 MITSUBISHI ECLIPSE ABS

17-6REAR SUSPENSION <2WD> - Three-link Suspension
SUSPENSION BUSHINGS
In order to improve both the driving stability and
riding comfort even further, and to reduce vibration
and noise, the optimum spring characteristic has
been employed for each suspension bushing.
The front end of the trailing arm is elastically
coupled to the body via a rubber bushing of high
spring capacity. This rubber bushing has an asym-
metrical non-linear characteristic in the front-rear
direction. and therefore functions to reduce thetransmission of tire vibration input to the body itself.
Individual independent bushings (with non-linear
characteristics) are also employed at the couplings
to the body of the shock absorbers and the coil
springs; these, together with the use of spring pads
with large channels, serve to reduce the transmis-
sion of vibrations to the body, thereby improving
even further the driving stability and riding comfort.
Lateral rod bushingBushina A
hannel
f3ub
Torsional
barArm
bushmg\/HollowHoilow
Section A-A

.-_. -
17-8REAR SUSPENSION <4WD> - Geneal information
REAR SUSPENSION <4WD>GENERAL INFORMATION
Rl7BEThe rear suspension is a newly developed double
wishbone independent suspension with a toe-in
correction feature utilizing compliance of thebushing to external force, and provides
excellesteering stability and a good ride.
The special features of this suspension include
l Optimum adjustment of suspensiongeometry
l Optimum adjustment of alignment
change
0 Passive toe-in correction function
l Optimum combination of spring constant,
shock absorber damping force. andbushing characteristics
l Elastic support of the doubleanti-vibration croSsmemberl Improvement of straight-forward
motion stability
0 Improvement of cornering
stability
l Improvement of steerability
l Good balance ofride andsteering stability
( , , :l Low noise and
low vibrationCONSTRUCTION DIAGRAM
absorber
Trailing arm
.
12AC

_ -. ..__ .-
REAR SUSPENSION
<4WD> - Geneal (nformation
THREE SIDE VIEWS
Trailil
12AOll
SPECiFiCATiONSItems
Suspension system
Coil springWire dia. x O.D.
x free lengthmm (in.)Coil spring identification
colourSpring constantN/mm
(kg/mm. Ibs.An.1
Shock absorberType
Max. lengthmm
(in.)Min. length
mm (in.)Stroke
mm (in.)
Damping force (at 0.3
m/set. (0.9 ft./sec.)l
Expansion
N (kg. Ibs.)Contraction
N (kg, Ibs.)Wheel alignment
Toe-in (left/right wheel difference)mm (in.)
CamberSpecifications
Double wishbone tvpe
11.0x106x332.5(.43x4.17x13.1)
Purple x 125.0
(2.50, 140)Hydraulic, cylindrical double-acting
We
568 (22.4)380
(15.0)
188 (7.4)900
(90. 198)300
(30.66)3.6
f 3 (.14 2 .I21
-1”33’ + 30’

17-14REAR SUSPENSION - Double Wishbone Suwension
REAR SHOCK ABSORBERThe rear shock absorber consists of a shock
absorber, coil spring, etc., arranged concentrically.
The shock absorber is a hydraulic cylinder of the
double action type with low sliding resistance, and
gives stable damping force.The inputs from the shock absorber and coil
spr,are borne by the upper bushings and spring pad,
respectively, for a better ride and lower vibration
and noise level. A polyurethane foam bump rubber
has been adopted for effective shock absorption in
the event of completely bottoming out.
Cap ,-&
Upper bushing A _
IlXk!! \Upper bushing Bx?nb
Spring padBump rubber

REAR SUSPENSION- Double Wishbone Suspension17-15TRAILING ARM
The trailing arm has a welded axle housing, knuckle
and shock absorber bracket. The axle housing is
machined after welded to the trailing arm to
improve its presicion. The arm has a connecting rod
for toe-in correction. The connecting rod consists ofa rod rubber and trailing arm bushing. It is inserted
into the trailing arm and can make a rotary motion
relative to the bolt.
Section A-A
bBBolt
ubber
RodRod12A0045
Ii
Connecting rod
Section C-C
Trailing armbushiyg
\Co;lnecting
rod1240043
Section B-B
Knuckleii-l /
Shock absorber bracket,,
I12ACO51

MANUAL TRANSAXLE <2WD> - Transaxle Control
21-5
IANSAXLE CONTROLFor transaxle control, a floor-shift system employing
cables for control has been adopted.
0Rubber vibration-absorbers have been provided
at the points of connection of the shift and
select cables to the transaxle and the body in
order to prevent the transmission of minor
vibrations to the body.l A vibration-absorbing steel plate has been
pro-vided at the shift lever bracket’s cable connec-
tion point in order to reduce the shifting noise.
l Shaking movement of the shift lever during
acceleration and deceleration has been attenu-
ated by the flexibility of the shift and select
cables.
Vibration-preventionrubber Dieces
Vibration-preventionrubber Dieces

21-10MANUAL TRANSAXLE <4WD> - General Information4WD SYSTEM OPERATION
Conventional 4WD systems (direct-coupled
4WD,or center differential type 4WDl have their own
merits and demerits; they rely on manual operation
(switching between 4WD and 2WD modes, center
differential locking) to cope with their demerits.
With this new 4WD system, the viscous coupling
built in the center differential automatically performssuch operations used to be made manually. The
driver can participate with the merits of 4WD at alltimes.The operation of the differential and the
viscous
coupling under representative conditions
are described in the following section.
I
Reardifferential
Center
differential
U differential
Viscous AuDk?TFNOO5’difference
ce271010i
TFMMYTFMMY
0
Turningdirection
ITFMOO!X
-.During normal driving
During normal driving (traveling straight on a level road at a
constant speed), the four wheels rotate at nearly the same
speed. Since there is no rotating speed difference among the
four wheels, the viscous coupling does not apply differential
limiting torque and the three differentials distribute drive power
equally to all of the wheels.
During a sharp turn
During a sharp turn, in addition to the rotating speed difference
between the left and right wheels, a small difference in rotati
speeds between the front and rear wheels also occurs.
Such rotational speed difference is absorbed by the differential
action of the three differentials, thereby allowing smooth
driving.The rotational speed difference is also transmitted to the
viscous coupling but the difference is so small that the coupling
makes almost no differential limiting torque application conse-
quently it does not affect the differential action of the center
differential.
When starting out and accelerating
When starting out and accelerating, the center of gravity of the
vehicle shifts towards the rear increasing the rear wheel load
and decreasing the front wheel load. The center
differenti”causes less drive power to be transmitted to the rear whee.
resulting in a lower driving torque. At the same time, however,
the rotational speed difference between the front and rear
wheels increases and the viscous coupling operates to limit the
differential action of the center differential. securing a supply of
drive power to the rear wheels. In this way, performance when
starting out and accelerating is secured.

21-14MANUAL TRANSAXLE t4WD> - Viscous Coupling (VCU)
Rotating speed difference
Transmitted
torque
TemperatureII I
t
/
IIc
P&e surface‘II I
preTYl-LLL
Hump mode2210llrHump phenomenon specific to viscous couplings
Hump is a phenomenon specific to viscous couplings
althob,, Iit does not occur under normal operating conditions.
This phenomenon occurs when the silicone oil temperature has
risen due to sustained differential action. Normally silicone oil
fills the space between the inner and outer plates, preventing
their direct coupling. When silicone oil expands at a high
temperature to such a degree as to develop abnormally high
pressure between the plates (normal thermal expansion is
absorbed by compression of air mixed in silicone oil), silicone oilescapes from between the plates. As a result, the plates
couple directly, causing abrupt torque transmission. When the
viscous coupling is directly coupled in this way, a rotating
speed difference does not exist, and then silicone oil tempera-
ture drops and normal function is restored.
Hump mode2210115