1991 LEXUS SC400 parking brake

PARKING BRAKE
BR03H±04
When the parking brake lever is pulled up, the parking brake shoe lever is p\
ulled via the parking brake wire.
This causes the shoe strut to push the front shoe, which expands and is pres\
sed against the disc. If the
parking brake lever continues to be pulled up, the contact point of the parking\
brake shoe lever and shoe
strut then becomes the fulcrum so that the parking brake shoe lever causes th\
e rear shoe to expand. This
results in the disc being locked by the front shoe and rear shoe.
±
BRAKE SYSTEM OPERATIONBR±3
WhereEverybodyKnowsYourName

4. CHECK THAT PEDAL RESERVE DISTANCE IS CORRECT,
AS SHOWN
Release the parking brake.
With the engine running, depress the pedal and measure the
pedal reserve distance, as shown.
Pedal reserve distance at 490 N (50 kgf, 110.2 lbf):
More than 89 mm (3.50 in.)
If the reserve distance is incorrect, troubleshoot the brake
system.
BRAKE BOOSTER OPERATIONAL TEST
BR03P±0B
1. OPERATING CHECK
(a) Depress the bake pedal several times with the engine off and
check that there is no change in the pedal reserve distance.
(b) Depress the brake pedal and start the engine. If the pedal goes down slightly, operation is normal.
2. AIR TIGHTNESS CHECK
(a) Start the engine and stop it after 1 or 2 minutes. Depress the brake pedal several times slowly. If the pedal goes down the
farthest the 1st time, but gradually rises after the 2nd or 3rd
time, the booster is air tight.
(b) Depress the brake pedal while the engine is running, and stop the engine with the pedal depressed. If there is no
change in the pedal reserve travel after holding the pedal for
30 seconds, the booster is air tight.
BRAKE SYSTEM BLEEDING
BR0ED±04
HINT: If any work is done on the brake system or if air in the
brake lines is suspected, bleed the system of air.
NOTICE: Do not let brake fluid remain on painted sur-
faces. Wash it off immediately.
1. REMOVE RESERVOIR CAP Turn the reservoir cap to the ªopenº side and remove it.
2. FILL RESERVOIR WITH BRAKE FLUID
Fluid: SAE J1703 or FMVSS NO.116DOT3
BR±8±
BRAKE SYSTEM CHECK AND ADJUSTMENT
WhereEverybodyKnowsYourName

PARKING BRAKE CHECK AND
ADJUSTMENT
BR03R±04
1. CHECK THAT PARKING BRAKE LEVER TRAVEL IS
CORRECT
Pull the parking brake lever all the way up, and count the
number of clicks.
Parking brake lever travel at 196 N (20 kgf, 44.1 lbf):
5±8 clicks
If incorrect, adjust the parking brake.
2. IF NECESSARY, ADJUST PARKING BRAKE HINT: Before adjusting the parking brake, make sure that the
rear brake shoe clearance has been adjusted.
For shoe clearance adjustment, see page BR±49.
(a) Remove the cup holder.
(b) Using a socket driver and spanner wrench, remove the adjusting lock nut.
HINT: Tape the socket driver before use.
(c) Turn the adjusting nut until the lever travel is correct.
(d) Install the adjusting lock nut.
(e) Using a socket driver and s panner wrench, tighten the
adjusting lock nut.
Torque: 5.4 N Vm (55 kgf Vcm, 48 in. Vlbf)
(f) Install the cup holder.
±
BRAKE SYSTEM CHECK AND ADJUSTMENTBR±11
WhereEverybodyKnowsYourName

REAR BRAKE
(Parking Brake)
COMPONENTS
BR04E±06
PARKING BRAKE DISASSEMBLY
BR04F±09
1. REMOVE REAR WHEEL
2. REMOVE REAR DISC BRAKE ASSEMBLY
(a) Remove the 2 mounting bolts and remove the disc brakeassembly.
(b) Suspend the disc brake so the hose is not stretched.
3. REMOVE DISC
(a) Place matchmarks on the disc and rear axle hub.
(b) Remove the disc. HINT: If the disc can not be removed easily, return the shoe
adjuster until the wheel turns freely.
BR±44
±
BRAKE SYSTEM REAR BRAKE (Parking Brake)
WhereEverybodyKnowsYourName

4. REMOVE SHOE RETURN SPRINGSUsing needle±nose pliers, remove the 2 shoe return springs.
5. REMOVE SHOE STRUT WITH SPRING
6. REMOVE FRONT SHOE ADJUSTER AND TENSION SPRING
(a) Slide out the front shoe and remove the shoe adjuster.
(b) Disconnect the tension spring and remove the front shoe.
7. REMOVE REAR SHOE
(a) Slide out the rear shoe.
(b) Remove the tension spring from the rear shoe.
(c) Disconnect the parking brake cable from the parking brake
shoe lever.
(d) Remove the shoe hold±down spring cups, springs and pins.
±
BRAKE SYSTEM REAR BRAKE (Parking Brake)BR±45
WhereEverybodyKnowsYourName

PARKING BRAKE COMPONENTS
INSPECTION AND REPAIR
BR04G±0B
1. INSPECT DISASSEMBLED PARTSInspect the disassembled parts for wear, rust or damage.
2. MEASURE BRAKE SHOE LINING THICKNESS Using a scale, measure the thickness of the shoe lining.
Standard thickness:
2.5 mm (0.098 in.)
Minimum thickness: 1.0 mm (0.039 in.)
If the lining thickness is at the minimum thickness or less, or
if there is extremely uneven wear, replace the brake shoe.
3. MEASURE BRAKE DISC INSIDE DIAMETER Using a vernier caliper, measure the inside diameter of the
disc.
Standard inside diameter:
190 mm (7.48 in.)
Maximum inside diameter: 191 mm (7.52 in.)
Replace the disc if the inside di ameter is at the maximum val-
ue or more. Replace the disc or grind it with a lathe if the disc
is scored or is worn unevenly.
4. INSPECT P ARKING BRAKE LINING AND DISC FOR
PROPER CONTACT
Apply chalk to the inside surface of the disc, then grind down
the brake shoe lining to fit. If the contact between the disc and
the brake shoe lining is improper, repair it using a brake shoe
grinder or replace the brake shoe assembly.
5. MEASURE CLEARANCE BETWEEN PARKING BRAKE SHOE AND LEVER
Using a feeler gauge, measure the clearance.
Standard clearance:
Less than 0.35 mm (0.0138 in.)
If the clearance is not within the specification, replace the
shim with one of the correct size.
BR±46
±
BRAKE SYSTEM REAR BRAKE (Parking Brake)
WhereEverybodyKnowsYourName

 
Thickness mm(in.) Thickness mm(in.)
 0.3 (0.012) 0.9 (0.035)
 

0.6 

(0.024) 


 


6. IF NECESSARY, REPLACE SHIM
(a) Remove the parking brake shoe lever, and install the correct
size shim.
(b) Install the parking brake shoe lever with a new Cwasher.
(c) Remeasure the clearance.
PARKING BRAKE ASSEMBLY
BR0ES±04
HINT: Assemble the parts in the correct direction, as shown.
1. APPLY HIGH TEMPERATURE GREASE ON BACK± ING PLATE
±
BRAKE SYSTEM REAR BRAKE (Parking Brake)BR±47
WhereEverybodyKnowsYourName

2. APPLY HIGH TEMPERATURE GREASE TO ADJUSTER
3. CONNECT PARKING BRAKE CABLE TO PARKINGBRAKE LEVER
(a) Install the shoe hold±down springs, cups and pins.
(b) Connect the parking brake cable to the parking brake shoe
lever of the rear shoe.
4. INSTALL REAR SHOE Slide in the rear shoe between the shoe hold±down spring
cup and the backing plate.
NOTICE: Do not allow oil or grease to get on the rubbing face.
5. INSTALL TENSION SPRING, FRONT SHOE ANDADJUSTER
(a) Install the tension spring on the rear shoe.
(b) Install the front shoe on the tension spring.
(c) Install the adjuster between the front and rear shoes.
(d) Slide in the front shoe between the shoe hold±down spring
cup and the backing plate.
BR±48
±
BRAKE SYSTEM REAR BRAKE (Parking Brake)
WhereEverybodyKnowsYourName