LEXUS SC400 1991 Service Repair Manual

ALTERNATIVE REFRIGERANTSPage 1 of 1
Beginning with the Montreal Protocol signed in April 1988, auto manufacturers wor\
ld±wide
committed to phase±out the use of ozone damaging Refrigerant R±12,\
also known as Freon.
All automobile manufacturers are re±designing new production vehicles\
to use non-ozone depleting
R±134a which is the only
universally approved replacement refrigerant for R±12.
All 1994 and newer Lexus use R±134a.
Several independent companies have begun marketing alternative refrigerants whi\
ch they claim can
replace R±12 when servicing vehicles in the dealership. These R±12 repla\
cements commonly
referred to as blends or hydrocarbon based refrigerants, have the potent\
ial to cause damage to
Lexus AC systems and in some cases can cause personal injury to the serv\
ice technician or the
end±user. Lexus strongly discourages the use of these refrigerants in Lexus vehicl\
es.
Furthermore, dealer technicians should be cautious of vehicles that may be labeled o\
r otherwise
identified to contain such refrigerants. Servicing these vehicles can contaminate your AC
refrigerant recovery equipment causing refrigerant stored in the recovery machine to be rendered
unusable. Also, if the contaminated refrigerant equipment is then used on subseq\
uent repairs, the
dealer may unknowingly contaminate other owner's vehicles.
For all Lexus models and years that are designed to operate on R±12, \
continue to service with
R±12 as long as it is available which is expected to be two or more years. When research is
complete and R±12 becomes difficult to acquire, Lexus will provide parts and procedures to properly
retrofit an R±12 vehicle to non±ozone depleting R±134a.
HEATING & AIR
CONDITIONING
AC94±001
MARCH 25, 1994
ALL MODELS
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DATE:NOVEMBER 29, 1996
TitleALTERNATE REFRIGERANTS AND A/C RETROFITPage 1 of 2
Effective January 1, 1996, the E.P.A. has officially banned the manufacture of Refrigerant 12 (Freon).
As a result, surplus supplies of R±12 will begin to dwindle over the ne\
xt several years until, eventually,
R±12 will no longer be available.
This uncertainty about the availability of R±12 has caused significant concerns for Lexus dealers when
servicing HVAC systems not using R±134a refrigerant. Similarly, the reduced availability of R±12 has
prompted demands for R±134a retrofit kits and/or alternate refrigerants. Thi\
s TSB will clarify Lexus's
current recommendations for servicing and retrofitting HVAC systems on Lexus vehicles using R±12
refrigerant.
ALTERNATE REFRIGERANTS:
Previously, the E.P.A. has endorsed other alternative refrigerants. These endorsements, combin\
ed with
the uncertain future availability of R±12, have lead to a limited accept\
ance of using alternative refrigerants
when servicing or retrofitting R±12 HVAC systems. Use of these refrigerants can lead to several service
related problems, including:
Poor system performance and leak detection capabilities.
Contamination of R±12 and R±134a during refrigerant recovery and r\
ecycling.
Recently the E.P.A. released a statement clarifying that approval of alternative refrige\
rants relates only
to the toxicology, flammability, ozone depletion and global warming characteristics. The approval does
not imply acceptability of alternative refrigerants use with respect to serviceability or performance.
TOYOTA MOTOR SALES, U.S.A. ENDORSES THE USE OF R±134a AS THE ONLY ACCEPTABLE ALTERNATIVE REFRIGERANT FOR VEHICLES USING R±12.
R±12 AVAILABILITY:
It is estimated that existing R±12 supplies will meet market demand i\
n 1996. Beyond that, Lexus will
supply R±12 to it's dealers from a strategic reserve. These strategic reserves are alloca\
ted specifically
for distribution to Lexus dealers for repair of their customers' R±12 H\
VAC systems. TMS projects these
reserves may meet dealer demand through early 1998. After that, we believe R±12 will no longer be re\
adi-
ly available and dealers will begin to retrofit customer vehicles with R\
±134a.
REF: HEATING & AIR CONDITIONING
NO:AC007±96
MODEL:ALL MODELS
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ALTERNATE REFRIGERANTS AND A/C RETROFITPage 2 of 2
RETROFIT ISSUES:
Lexus has completed development of retrofit parts for all later model Le\
xus vehicles using R±12 refrigerant.
These parts will be produced in harmony with market demand, based on R±12 \
availability.
The parts necessary for a typical retrofit will generally include:Receiver Dryer
O±Rings
Fittings
Labels
Oil
A TSIB outlining retrofit procedures will be released when the retrofit \
kits become available.
For additional information, contact the Environmental Assistance Network\
Hotline at 1±800±542±3914.
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COIL SPRING COMPRESSOR SST # 09727-30020-02Page 1 of 1
Please observe the following procedures each time this tool is used:
SPECIAL SERVICE TOOLS
SS93±001
MARCH 12, 1993
ALL MODELS
Carefully inspect your spring compressor for cracks or other deformation prior to
each use.

Use only on Lexus vehicles. Use on other applications may exceed the tool design
limits.
 Be sure spring is free from its seat (unstuck) prior to compressing.
 Do not compress the coil spring further than needed to facilitate the repair.
When using suspension coil spring compressor be sure to follow the instructi\
ons outlined in
the repair manual as well as the caution label placed on the tool (see illustration below).
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QTY
PART NUMBER
PART NAME
CHANGE IN SUPPLY PARTS FOR INNER REAR VIEW MIRROR Page 1 of 3
Supply parts for the inner rear view mirror have been changed from an assembly to the com-
ponents listed below.
PART NUMBER INFORMATION:
BODY
BO92±008
DECEMBER 4, 1992
SC 300/400
87825±24010 1Spring, Inner Rear View Mirror Body Setting
DESCRIPTION
87808±24010 2Holder Subassembly,
Inner Rear View Mirror
87817±24010 1Spacer, Inner Rear View Mirror
N/A N/A Not available as a
separate supply part
This part is attached to windshield. Use original part or replace windshield\
and mirror base
as an assembly, if necessary.
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CHANGE IN SUPPLY PARTS FOR INNER REAR VIEW MIRROR (CONT'D)Page 2 of 3
1) Remove Center Visor
a) Remove the visor arm set clip (Figure 1).
b) Remove the two attachment screws.
Figure 1
Figure 2
Figure 3
Figure 4 2) Remove Inner Rear View Mirror
a) Remove mirror set screw (Figure 2).
b) Disconnect the mirror wire harness.
INNER REAR VIEW MIRROR REMOVAL:
Note: To prevent damage to plastic parts,
tape the screwdriver tip before use.
COMPONENT DISASSEMBLY:
a) Using snap ring pliers, remove the spring.
b) Remove the two holders and the spacer (Figure 3).
NOTE: Do not remove the mirror base from the windshield.
COMPONENT ASSEMBLY:
a) Reinstall components by installing the spacer, two holders and spring.
b) Install the spring using snap ring pliers (Figure 4).
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CHANGE IN SUPPLY PARTS FOR INNER REAR VIEW MIRROR (CONT'D)Page 3 of 3
a) Install inner rear view mirror by re±installing
attachment set screw (Figure 5).
INNER REAR VIEW MIRROR & CENTER
VISOR INSTALLATION:
PARTS LOCATION:
Note: Use thread locking compound on
set screw to ensure screw reten-
tion.
b) Re±connect wire harness.
Note: Check review mirror dimming operation before re±installation of
center visor.
c) Install center visor by re±installing two attachment screws.
d) Re±install visor arm set clip.
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REAR SUSPENSION NOISEPage 1 of 2
PREVIOUS PART
NUMBER
48341-24040
48341-24070
Center Support Nut
Projection
New
Rear Spring Bumper
Previous
Rear Spring Bumper
SUSPENSION
SU95±005
OCTOBER 20, 1995
SC 300/400
The rear spring bumper has been changed in production on 1995 SC 300/400 in\
an effort to reduce
clunking/rattling noises.
SERVICE HINT: A similar clunking/rattling type noise can be generated by an
improperly torqued center support nut (27 N m, 280 kgf.cm,
20 ft.lbs).
PRODUCTION EFFECTIVE
:
Starting VINs: JT8UZ30C*S0047966 JT8JZ31C*S0030524
PART NUMBER INFORMATION
: NEW PART NUMBER PART NAME QTY
48341-24071 Bumper, Rear Spring 2
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REAR SUSPENSION NOISEPage 2 of 2
WARRANTY INFORMATION:
OPCODE DESCRIPTION TIME OPN T1 T2
R&R Rear Shock AbsorberAssembly
(both sides including 48341-24040 or
replacement of spring 48341-24070
bumpers and all necessary
adjustments)
Replacement of the rear spring bumper under warranty is limited to correction of a prob\
lem based upon a
customer 's complaint.
482201A 1.8 91 41
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SERVICE HINTS FOR REFRIGERANT LEAK DETECTIONPage 1 of 3
Use of electronic leak detectors for checking A/C systems refrigerant leaka\
ge is the only
method approved by TMS. This type of leak detector is sensitive not onl\
y to refrigerant, but
also sensitive to numerous petrochemical substances (motor oil, gasolin\
e, solvents, etc.)
commonly found in a repair shop environment. Because this sensitivity c\
ould diminish the leak
detector 's capacity for accurate leak detection, some service hints have been pro\
vided to help
increase the accuracy of your diagnosis.
SERVICE HINTS:
1. Visual Inspection: Do a quick visual inspection under the hood for signs of refrigerant
leakage. Check for areas of heavy oil leakage at block and piping joint\
s. Many times
these areas have accumulated road dust and dirt.
2. Inspection with leak detector: NOTE: Make sure the system is fully charged. Operate
the system to increase refrigerant pressure. Shut the system off before inspecting with
leak detector.
A. Checking for leakage at a joint:
Wipe the oil/dirt accumulation off the joint with a
clean rag. Do not use solvents to clean the joint. Refrigerant is heavi\
er than air so
start checking for leaks with the detector wand about 1/4 in. below the \
joint. Move the
wand slowly across and around each joint (see illustration below).
Piping Joint Move detector wand slowly across
and around each joint.
Block Joint
HEATING &
AIR CONDITIONING
AC95±001
MARCH 03, 1995
ALL MODELS
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