Basic Brake System - Lancer: Diagnosis Mitsubishi Lancer X

BASIC BRAKE SYSTEM DIAGNOSTIC TROUBLESHOOTING STRATEGY

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

SYMPTOM CHART

DIAGNOSIS

1. 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 .
2. STEP 2. Check disc brake pistons for smooth operation . With engine not running, depress the brake pedal rapidly several times to deplete booster vacuum reserves. Test each disc brake assembly one at a time. Remove the lower caliper bolt, then remove caliper from mount. 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 «DISASSEMBLY AND ASSEMBLY < VEHICLES WITH 16-INCH WHEEL>»(ref-291270-S17418214012008072500000) < Vehicles with 16-inch wheel> or «DISASSEMBLY AND ASSEMBLY < VEHICLES WITH 18-INCH WHEEL>»(ref-291270-S14392520522008072500000) < Vehicles with 18-inch wheel>, Rear: refer to «DISASSEMBLY AND ASSEMBLY < VEHICLES WITH 16-INCH WHEEL>»(ref-291270-S05159414092008072500000) < Vehicles with 16-inch wheel> or «DISASSEMBLY AND ASSEMBLY < VEHICLES WITH 18-INCH WHEEL>»(ref-291270-S32508465562008072500000) < Vehicles with 18-inch wheel>). Then go to Step 5 .
3. STEP 3. Check brake disc(s) for runout . Refer to «DISC BRAKE ROTOR CHECK»(ref-291270-S32577232362008072500000) . 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 .
4. STEP 4. Check brake discs for correct thickness . Refer to «DISC BRAKE ROTOR CHECK»(ref-291270-S32577232362008072500000) . 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 .
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.

Scheme 50

1. STEP 1. Check whether the brake fluid is low, is the correct fluid (A/T fluid, engine oil, etc.) or is contaminated (debris, sand, etc) . Q: Is there fault? YES : Refill or replace with the specified brake fluid DOT 3 or DOT 4. Bleed the brakes if necessary (Refer to «BLEEDING»(ref-291270-S38620719812008072500000) ). Then go to Step 9 . NO : Go to Step 2 .
2. STEP 2. Check for spongy (not firm brakes) . With engine not running, depress the brake pedal rapidly several times to deplete booster vacuum reserve. With the brake pedal fully released, depress the brake pedal slowly until it stops. With a measuring stick (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 (Refer to «BLEEDING»(ref-291270-S38620719812008072500000) ). Then go to Step 9 . NO : Go to Step 3 .
3. STEP 3. Check the lining and brake drum contact. < Vehicles equipped with rear drum brake> If equipped with rear disc brake, go to Step 5 . Put chalk on the inner surface of the brake drum. Rub the lining against the drum inner surface. NOTE: Clean off chalk after check. Q: Does the lining wipe off or smudge the chalk across the full width of the lining? YES : Go to Step 5 . NO : Replace the shoe and lining assemblies on both sides. Go to Step 9 .
4. STEP 4. Check the auto adjuster function. < Vehicles equipped with rear drum brake> Refer to «AUTO ADJUSTER FUNCTION CHECK < VEHICLES WITH REAR DRUM BRAKE>»(ref-291270-S22965221142008072500000) . Q: Is there fault? YES : Repair it. Then go to Step 9 . NO : Go to Step 5 .
5. STEP 5. Check the brake booster function . Refer to «BRAKE BOOSTER OPERATION CHECK»(ref-291270-S16025242002008072500000) . Q: Is there fault? YES : Replace the part. Then go to Step 9 . NO : Go to Step 6 .
6. STEP 6. Check for pinched or restricted brake tube or hose . Q: Is there pinched or restricted brake tube or hose? YES : Replace that complete section of brake tube or brake hose. Then go to Step 9 . NO : Go to Step 7 .
7. STEP 7. Check for oil, water, etc., on the pad or lining contact surfaces of all brakes . Q: Is oil, water, etc., on the pad or lining contact surface? YES : Replace the part and determine and repair source/cause of foreign material. Recheck symptom. Then go to Step 9 . NO : The procedure is complete. If condition persists, go to Step 8 .
8. STEP 8. Check the proportioning valve operation . Refer to «CHECK VALVE OPERATION CHECK»(ref-291270-S29435149292008072500000) . Q: Is there fault? YES : Replace the part. Then go to Step 9 . NO : Go to Step 9 .
9. STEP 9. 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»(ref-291270-S21981257522008072500000) .

1. STEP 1. Check for spongy (not firm) brakes . With engine not running, depress the brake pedal rapidly several times to deplete booster vacuum reserve. With the brake pedal fully released, depress the brake pedal slowly until it stops. 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 (Refer to «BLEEDING»(ref-291270-S38620719812008072500000) ). Then go to Step 6 . NO : Go to Step 2 .
2. STEP 2. Check the pad for wear . Refer to «BRAKE FLUID LEVEL SWITCH CHECK»(ref-291270-S04371319722008072500000) . Q: Is the pad thickness outside of specifications? YES : Replace the part. Then go to Step 6 . NO : Go to Step 3 .
3. STEP 3. Check the vacuum hose and check valve for damage . Refer to «CHECK VALVE OPERATION CHECK»(ref-291270-S29435149292008072500000) . Q: Is there a damage? YES : Replace the part. Then go to Step 6 . NO : Go to Step 4 .
4. STEP 4. «CHECK THE MASTER CYLINDER FUNCTION»(ref-291270-S16442778362008072500000) . Refer to «BRAKE PEDAL»(ref-291270-S17112925442008072500000) Q: Is there a fault? YES : Repair it. Then go to Step 6 . NO : Go to Step 5 .
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 6 . NO : Go to Step 6 .
6. STEP 6. 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»(ref-291270-S21981257522008072500000) .

Scheme 51

1. STEP 1. Check the parking brake lever return . Q: Is the operation faulty? YES : Repair it. Then go to Step 7 . NO : Go to Step 2 .
2. STEP 2. Check the brake shoe springs for breakage . Q: Are the brake shoe springs broken? YES : Replace the spring. Then go to Step 7 . NO : Go to Step 3 .
3. STEP 3. Check the amount of grease at each sliding section . Refer to «REAR DRUM BRAKE < VEHICLES WITH REAR DRUM BRAKE>»(ref-291270-S15857758692008072500000) or «PARKING BRAKE LINING AND DRUM»(ref-291290-S24115685622008072500000) . Q: Is the grease amount low? YES : Apply grease. Then go to Step 7 . NO : Go to Step 4 .
4. STEP 4. Check the parking brake pull amount . Refer to «PARKING BRAKE LEVER STROKE CHECK AND ADJUSTMENT»(ref-291290-S09357202112008072500000) . Q: Is there a fault? YES : Adjust it. Then go to Step 7 . NO : Go to Step 5 .
5. STEP 5. Check port for clogging . Q: Is the port clogged? YES : Repair it. Then go to Step 7 . NO : Go to Step 6 .
6. STEP 6. Check disc brake pistons for sticking . Depress the brake pedal, then release. Confirm each wheel spins freely. Q: Does any wheel stick? YES : Inspect that brake assembly. Then go to Step 7 . NO : Go to Step 7 .
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»(ref-291270-S21981257522008072500000) .

Scheme 52

1. STEP 1. Check the front brakes, then rear brakes, for metal-to-metal condition . Q: Is any metal-to-metal contact evident? YES : Repair or replace the components. Then go to Step 6 . NO : Go to Step 2 .
2. STEP 2. Check for interference between the caliper and wheel . Q: Is there any interference? YES : Repair or replace the part. Then go to Step 6 . NO : Go to Step 3 .
3. STEP 3. Check for interference between the dust cover and brake disc . Q: Is there any interference? YES : Repair or replace the part. Then go to Step 6 . NO : Go to Step 4 .
4. STEP 4. Check the brake drums or discs for cracks . Q: Are there cracks? YES : Repair or replace the part. Then go to Step 6 . NO : Go to Step 5 .
5. STEP 5. Check for bent backing plate(s) . Q: Is (Are) the backing plate(s) bent? YES : Repair or replace the part. Then go to Step 6 . NO : Go to Step 6 .
6. STEP 6. 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»(ref-291270-S21981257522008072500000) .

1. STEP 1. Check the brake disc and pads for wear or cutting . Q: Is there wear or cutting? YES : Repair or replace the part. Then go to Step 4 . NO : Go to Step 2 .
2. STEP 2. Check the calipers for rust . Q: Is there any rust? YES : Remove the rust. Then go to Step 4 . NO : Go to Step 3 .
3. STEP 3. Adjust the brake pedal . Refer to «BRAKE PEDAL CHECK AND ADJUSTMENT»(ref-291270-S02903833612008072500000) . Q: Is the brake pedal adjusted correctly? YES : Go to Step 4 . NO : Adjust the brake pedal. Then go to Step 4 .
4. STEP 4. 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»(ref-291270-S21981257522008072500000) .

Scheme 53

Scheme 54

Scheme 55

1. STEP 1. Check whether the backing plate is bent or loose and interfering with the drum . Q: Is there a fault? YES : Replace the part. Then go to Step 8 . NO : Go to Step 2 .
2. STEP 2. Check whether the drum is damaged due to interference with the backing plate or shoe . Q: Is there any damage? YES : Replace the part. Then go to Step 8 . NO : Go to Step 3 .
3. STEP 3. Check the brake drum for wear and the shoe spring for damage . Q: Is there any wear or damage? YES : Replace the part. Then go to Step 8 . NO : Go to Step 4 .
4. STEP 4. Check the brake discs for rust . Q: Are the brake discs rusted? YES : Remove the rust by using sand paper. If still rusted, turn the rotors with an on-the-car brake lathe. Then go to Step 8 . NO : Go to Step 5 .
5. STEP 5. Check the brake pads for correct installation . Q: Are the pads installed incorrectly? YES : Install the pads correctly. Then go to Step 8 . NO : Go to Step 6 .
6. STEP 6. Check the calipers for correct installation . Q: Are the calipers installed incorrectly? YES : Install the calipers correctly. Then go to Step 8 . NO : Go to Step 7 .
7. STEP 7. Check the wheel bearings for end play . (1)Remove the brake discs or drums. Place a dial gauge as shown, and measure the end play while moving the hub in the axial direction. Limit: 0.05 mm (0.002 inch) Q: Does the measured end play exceed the limit? YES : Replace the faulty hub assembly. Then go to Step 8 . NO : Go to Step 8 .
8. STEP 8. 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»(ref-291270-S21981257522008072500000) .

Scheme 56

Scheme 57

1. STEP 1. Check whether foreign material has entered the wheel covers . Q: Is there any foreign material? YES : Remove it. Then go to Step 5 . NO : Go to Step 2 .
2. STEP 2. Check for looseness of the wheel nuts . Q: Are the wheel nuts loose? YES : Tighten to 98 ± 10 N.m (73 ± 7 ft-lb). Then go to Step 5 . NO : Go to Step 3 .
3. STEP 3. Check for looseness of the caliper installation bolt . Q: Is the caliper installation bolt loose? YES : Tighten to 100 ± 10 N.m (74 ± 7 ft-lb) for the front caliper. Tighten to 55 ± 5 N.m (41 ± 3 ft-lb) for the rear caliper. Then go to Step 5 . NO : Go to Step 4 .
4. STEP 4. Check the wheel bearings for end play . (1)Remove the brake discs or drums. Place a dial gauge as shown, and measure the end play while moving the hub in the axial direction. Limit: 0.05 mm (0.002 inch) Q: Does the measured end play exceed the limit? YES : Replace the faulty hub assembly. Then go to Step 5 . NO : Go to Step 5 .
5. STEP 5. 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»(ref-291270-S21981257522008072500000) .

PROPORTIONING VALVE FUNCTION TEST < Vehicles without ABS

Scheme 58

Scheme 59

1. Connect two pressure gauges to the output port of the master cylinder and output port of the proportioning valve.
2. Bleed the brake line and the pressure gauges (Refer to «BLEEDING OF BRAKE PIPELINE»(ref-291270-S32170456972008072500000) ).
3. Depress the brake pedal gradually. Then check that the split point, where the output fluid pressure begins to drop in proportion to the output fluid pressure, is at the standard value. Standard value: 2.21 - 2.70 (320 - 391) < Vehicles with rear drum brake> 1.81 - 2.21 (262 - 320) < Vehicles with rear disc brake>
4. Depress the brake pedal more strongly than at the above step. Then check that the output fluid pressure is at the standard value when the input fluid pressure is 6.86 MPa (996 psi). Standard value: 3.29 - 3.82 (477 - 554) < Vehicles with rear drum brake> 2.33 - 3.46 (338 - 501) < Vehicles with rear disc brake>
5. Measure each output fluid pressure at both valves, and check that the difference between the two is at the limit value or less. Limit: 0.5 MPa (73 psi)
6. If the measured pressure exceeds the limit, replace the proportioning valve.

PAD WEAR INSPECTION

Measure the pad thickness at the most worn area. If the pad thickness is less than the limit value, replace the pad.

Standard value: 10.0 mm (0.39 inch)

Minimum limit: 2.0 mm (0.08 inch)

Scheme 60

Measure the pad thickness at the most worn area. If the pad thickness is less than the limit value, replace the pad assembly.

Standard value: 10.0 mm (0.39 inch)

Minimum limit: 2.0 mm (0.08 inch)

Scheme 61