Brakes - Modifications to Improve Brake Feeling

91lexus01

BRAKES
006
JANUARY 18,1991
LS400


Title BRAKE FEELING

FIG. 1:

The following modifications have been made to improve brake feeling on LS400.

1. The master cylinder diameter has been changed from 1.0 in. (25.4 mm) to 1.1 in. (26.9 mm).
2. The booster jumping characteristics have been changed from 20kg to 28kg.
3. The front disc brake calipers have been changed from a single piston type to a double piston type (see fig.1).

FIG.2:

4. The front brake disc thickness has been changed from 0.98 in.(25 mm) to 1.10 in.(28 mm)(see fig. 2).
Note: The rotor diameter has not been changed.


NOTICE: When replacing the front brake disc's only on 1990 vehicles, verify the number of pistons in the front caliper and select the appropriate brake disc. 1990 model calipers with one (1) piston use brake disc part number 43512-50040. 1991 model calipers with two (2) pistons use part number 43512-50060.


PRODUCTION EFFECTIVE:

Vin # PRODUCTION DATE
JT8UF11E # M0046854 08/90


PART NUMBER INFORMATION:

1990 Model Part No. 1991 Model Part No. Part Name

(Without TRAC)
47201 - 50010 47201 - 50050 Cylinder Sub-Assy, Brake Master
44610 - 50010 44610 - 50050 Booster Assy, Brake
47730 - 50010 47730 - 50030 Cylinder Assy, R/F Disc Brake
47750 - 50010 47750 - 50030 Cylinder Assy, UF Disc Brake
43512 - 50040 43512 - 50060 Disc, Front Brake

(With TRAC)
47201 - 50020 47201 - 50060 Cylinder Sub-Assy, Brake Master
44610 - 50020 44610 - 50060 Booster Assy, Brake
47730 - 50010 47730 - 50030 Cylinder Assy, R/F Disc Brake
47750 - 50010 47750 - 50030 Cylinder Assy, L/F Disc Brake
43512 - 50040 43512 - 50060 Disc, Front Brake


Caution: 1991 Model parts should only be installed on 1990 Model vehicles as a complete set.

Note: 1991 Model parts should only be used on vehicles with the complaint of poor brake feeling. For routine service replacements on 1990 Models, use the 1990 production parts.