Mitsubishi 380. Manual — part 292
GENERAL DESCRIPTION
BASIC BRAKE SYSTEM
35A-2
GENERAL DESCRIPTION
M1351000100440
The brake system has been designed to give greater
reliability and durability and to provide excellent brak-
ing performance.
FEATURES
.
Improved braking performance
1. An 8+9 inch tandem brake booster provides suffi-
cient braking force in sudden braking range.
2. 296mm front ventilated disc brakes provide sta-
ble braking force and improved braking feel.
3. 303mm rear ventillated disc brakes are used.
.
Improved stability
1. A 4-wheel anti-lock braking system (4ABS) pre-
vents slipping caused by the vehicle wheels lock-
ing up, in order to maintain a stable vehicle
posture and steering performance.
2. An electronic brake-force distribution (EBD)
makes it possible to maintain the maximum
amount of braking force even when the vehicle's
load is unevenly distributed.
3. Front- and rear-wheel X-type brake line layout
are used.
4. Ventilated discs brakes improve anti-fading per-
formance.
.
Improved serviceability
1. A diagnosis function for the ABS system makes
inspection easier.
2. An outer disc separated hub and rotor make
removal and installation easier.
3. The master cylinder reservoir is utilised for both
brake and clutch fluid on manual transmission
vehicles.
4. The master cylinder filter is coloured black for
improved viewing.
5. The ABS-ECU and hydraulic unit are integrated
to make them more compact and light weight.
CONSTRUCTION DIAGRAM
BRAKE BOOSTER
HYDRAULIC UNIT
(INTEGRATED WITH
THE ABS-ECU)
MASTER CYLINDER
FRONT DISC BRAKE
REAR DISC BRAKE
<VEHICLE WITH ABS>
BASIC BRAKE SYSTEM DIAGNOSIS
BASIC BRAKE SYSTEM
35A-3
BASIC BRAKE SYSTEM DIAGNOSIS
INTRODUCTION TO BASIC BRAKE SYSTEM DIAGNOSIS
M1351009700319
Hydraulic brakes are composed of the brake pedal,
master cylinder, brake booster and disc brakes. Mal-
functions such as insufficient braking power or the
generation of noise may occur due to wear, damage
or incorrect adjustment of these components.
BASIC BRAKE SYSTEM DIAGNOSTIC TROUBLESHOOTING STRATEGY
M1351009800316
Use these steps to plan your diagnostic strategy. If
you follow them carefully, you will be sure that you
have exhausted most of the possible ways to find a
basic brake system fault.
1. Gather information from the customer.
2. Verify that the condition described by the
customer exists.
3. Find the malfunction by following the symptom
chart.
4. Verify malfunction is eliminated.
SYMPTOM CHART
M1351009900324
SYMPTOM PROCEDURES
INSPECTION PROCEDURE 1: Vehicle Pulls to One Side when Brakes are Applied
.
DIAGNOSIS
STEP 1. Check for oil, water, etc., on the pad
contact surface of all brakes.
Q: Is oil, water, etc., on the pad contact surface?
YES :
Replace the part and determine the
source/cause of foreign material. Then go to
Step 5.
NO :
Go to Step 2.
SYMPTOM
INSPECTION
PROCEDURE
REFERENCE
PAGE
Vehicle pulls to one side when brakes are applied
1
Insufficient braking power
2
Increased pedal stroke (Reduced pedal-to-floor board clearance)
3
Brake drag
4
Scraping or grinding noise when brake are applied
5
Squealing, groaning or chattering noise when brake are applied
6
Squealing noise when brakes are not applied
7
Groaning, clicking or rattling noise when brakes are not applied
8
BASIC BRAKE SYSTEM DIAGNOSIS
BASIC BRAKE SYSTEM
35A-4
STEP 2. Check disc brake pistons for smooth
operation.
(1) With engine not running, depress the brake pedal
rapidly several times to deplete booster vacuum
reserves.
(2) Test each disc brake assembly one at a time.
a. Remove the lower caliper bolt, then remove
caliper from mount.
b. Have an assistant slowly depress the brake
pedal. Confirm piston(s) extend slowly and
smoothly with no jumpiness. Repeat for each
disc brake assembly.
Q: Do (does) the piston(s) move correctly?
YES :
Go to Step 3.
NO :
Disassemble and inspect the brake
assembly (Front: refer to
, Rear:
). Then go to Step 5.
STEP 3. Check brake disc(s) for runout.
Refer to
Q: Is runout outside of specifications?
YES :
Repair or replace the brake disc(s) as
necessary. Then go to Step 5.
NO :
Go to Step 4.
STEP 4. Check brake discs for correct thickness.
Refer to
Q: Is the thickness outside of specifications?
YES :
Repair or replace the brake disc(s) as
necessary. Then go to Step 5.
NO :
Perform the brake line bleeding. Then go to
Step 5.
STEP 5. Retest the system.
Q: Is the symptom eliminated?
YES :
The procedure is complete.
NO :
Start over at Step 1. If a new symptom
appears, refer to the appropriate symptom
chart.
INSPECTION PROCEDURE 2: Insufficient Braking Power
.
DIAGNOSIS
STEP 1. Check that the specified brake fluid is
used, its level is correct, and no contamination is
found.
Q: Is there a fault?
YES :
Refill or replace with the specified brake
fluid DOT 3 or DOT 4. Bleed the brakes if
necessary (Refer to
). Then go to
Step 7.
NO :
Go to Step 2.
STEP 2. Check for spongy (not firm) brakes.
(1) With engine not running, depress the brake pedal
rapidly several times to deplete the booster
vacuum reserve.
(2) With the brake pedal fully released, depress the
brake pedal slowly until it stops.
(3) With a measuring device (ruler, etc.) next to the
brake pedal, depress the pedal firmly and
measure the distance the pedal traveled.
Q: Is the distance greater than 20 mm (0.8 inch)?
YES :
Bleed the brakes to remove air in the fluid
). Then go to Step 7.
NO :
Go to Step 3.
STEP 3. Check the brake booster function.
Refer to
Q: Is there a fault?
YES :
Replace the brake booster. Then go to Step
NO :
Go to Step 4.
BASIC BRAKE SYSTEM DIAGNOSIS
BASIC BRAKE SYSTEM
35A-5
STEP 4. Check for pinched or restricted brake
tube or hose.
Q: Is there a pinched or restricted brake tube or hose?
YES :
Replace that complete section of brake tube
or brake hose. Then go to Step 7.
NO :
Go to Step 5.
STEP 5. Check for oil, water, etc., on the pad
contact surfaces of all brakes.
Q: Is oil, water, etc., on the pad contact surface?
YES :
Replace the part and determine the
source/cause of foreign material. Recheck
symptom. Then go to Step 7.
NO :
The procedure is complete. If condition
persists for vehicles without ABS, go to Step
6.
STEP 7. Recheck symptom.
Q: Is the symptom eliminated?
YES :
The procedure is complete.
NO :
Start over at step 1. If a new symptom
surfaces, refer to the appropriate symptom
chart.
INSPECTION PROCEDURE 3: Increased Pedal Stroke (Reduced Pedal-to-Floor Board Clearance)
.
DIAGNOSIS
STEP 1. Check for spongy (not firm) brakes.
(1) With engine not running, depress the brake pedal
rapidly several times to deplete booster vacuum
reserve.
(2) With the brake pedal fully released, depress the
brake pedal slowly until it stops.
(3) With a measuring device (ruler, etc.) next to the
brake pedal, depress the pedal firmly and
measure the distance the pedal traveled.
Q: Is the distance greater than 20 mm (0.8 inch)?
YES :
Bleed the brakes to remove air in the fluid
NO :
Go to Step 2.
STEP 2. Check the pad for wear.
Refer to
Q: Is the pad thickness outside of specifications?
YES :
Replace the part. Then go to Step 7.
NO :
Go to Step 3.
STEP 3. Check the vacuum hose and check valve
for damage.
Refer to
Q: Is there a damage?
YES :
Replace the part. Then go to Step 7.
NO :
Go to Step 4.
STEP 4. Check the master cylinder function.
Refer to
Q: Is there a fault?
YES :
Repair it. Then go to Step 7.
NO :
Go to Step 5.
STEP 5. Check for brake fluid leaks.
Q: Is there a leak?
YES :
Check the connection for looseness,
corrosion, etc. Clean and repair as
necessary. If leaking in any tube or hose
section, replace the complete tube or hose.
Then go to Step 7 .
NO :
Go to Step 6.
STEP 6. Check for excessive clearance between
the push rod and primary piston.
Refer to
Q: Is the clearance outside of specifications?
YES :
Adjust the clearance. Then go to Step 7.
NO :
Go to Step 7.
STEP 7. Recheck symptom.
Q: Is the symptom eliminated?
YES :
The procedure is complete.
NO :
Start over at step 1. If a new symptom
surfaces, refer to the symptom chart.
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