Disc - x3 BMW X3 E83

DESCRIPTION & OPERATION

Note. For information on Anti-Lock Brake Systems (ABS), see appropriate ANTI-LOCK/TRACTION CONTROL article.

The brake system is one of the most important safety systems on any motor vehicle. For this reason it is necessary to exercise particular caution when working on the brake system and to comply with all instructions.

Brake system is a hydraulic dual-circuit brake system with "front/rear split", vacuum boost power assist and Electronic Brake Force Distribution (EBV). There is one brake circuit each for front and rear axles. The parking brake actuating unit is located in the center console and is equipped with an Automatic Cable Adjuster (ASZE) and a compensating element.

Parking brake is cable actuated on rear brake and consists of internally mounted parking brake shoes. Basic adjustment of the parking brake is required whenever

1. Brake shoes are replaced.
2. Brake discs are replaced.
3. Bowden cable is replaced.
4. Bowden cable guide tube is replaced.
5. Adjusting unit is reset.
6. Actuating stroke is excessive.

BLEEDING PROCEDURES

Note. Check relevant operating instructions for each device. Charging pressure should not exceed 29 psi (2 bar).

1. Connect BMW Diagnosis and Information System (DIS).
2. Call up service function BLEEDING ABS/DSC3 HYDRAULICS.
3. Connect bleeding unit to expansion tank and switch on.
4. To flush system completely see «FLUSHING BRAKE SYSTEM COMPLETELY»(/bmw/x3/e83-2003-2006/remont/mechanical-hydraulic/#disc-x3__flushing-brake-system-completely) .
5. To only bleed front or rear system see «BLEEDING FRONT OR REAR-AXLE BRAKE CIRCUIT»(/bmw/x3/e83-2003-2006/remont/mechanical-hydraulic/#disc-x3__bleeding-front-or-rear-axle-brake-circuit) .
6. Switch off bleeder unit and disconnect from expansion tank.
7. Check brake fluid level.
8. Close expansion tank. Take care of rubber gasket in lid.

Flushing Brake System Completely

1. Connect bleeder hose with container to bleed valve on rear right brake caliper.
2. Open bleed valve and flush until clear, bubble-free brake fluid emerges.
3. Close bleeder valve.
4. Follow same procedure at rear left, front right, then front left calipers.

Bleeding Front Or Rear-Axle Brake Circuit

1. Connect bleeder hose with container to bleed valve on right brake caliper.
2. Open bleed valve.
3. Run bleeding routine with BMW Diagnosis and Information System (DIS) with bleeder valve open.
4. After running routine, press brake pedal 5 times to stop. Clear, bubble-free brake fluid must flow out.
5. Close bleeder valve.
6. Repeat procedure at left caliper.

PARKING BRAKE

Note. Accurate adjustment of parking brake is only possible if parking brake Bowden cables and all moving parts move easily and function correctly.

Note. Numbers in text refer to numbers in figures.

Basic parking brake adjustment is necessary

1. When replacing parking brake shoes.
2. When replacing brake discs.
3. When actuation stroke exceeds 10 teeth.
4. When replacing parking brake Bowden cables.

To adjust parking brake, perform the following

1. Using Special Tool (32 1 030), press stop (1) of adjusting spring back until retaining hook (2) engages in stop (1). (Scheme 1) This will lock adjuster unit (ASZE).
2. Remove one wheel lug bolt on each rear wheel. Turn wheel until adjustment screw is visible in lug bolt hole.
3. Turn adjusting screw with a screwdriver until it is no longer possible to turn wheel. (Scheme 2)
4. Unfasten adjusting screw 6 notches.
5. Lever restraint hook (2) outwards with a suitable screwdriver (1). (Scheme 3) Restraint hook (2) must disengage from stop of adjusting spring. This will unlock adjuster unit (ASZE).
6. Install and tighten wheel lug bolt to specification. See «TORQUE SPECIFICATIONS»(/bmw/x3/e83-2003-2006/remont/mechanical-hydraulic/#disc-x3__torque-specifications).

Scheme 1

Scheme 2

Scheme 3

TROUBLESHOOTING

Brake performance is mainly affected by 3 things: the level and condition of the brake fluid, the brake system's ability to create and maintain hydraulic pressure, and condition of the friction components. Tires and wheels are important parts of the braking system. Check tires for wear, flat spots, trueness and proper inflation. Visually check the hydraulic system starting at the master cylinder. Check all brake fluid lines and couplings for leaks, kinks, chafing and corrosion.

On vehicles with vacuum brake booster, check brake booster by pumping brake pedal approximately 12 times with the engine off. Then hold down brake pedal and start engine. Pedal should fall slightly. If not, check for any visible faults before suspecting a faulty brake booster. Check for strong vacuum at vacuum hose fitting on booster. Ensure vacuum check valve has one-way flow. For trouble shooting symptoms, see SYMPTOM INDEX table.

SYMPTOM INDEX

SYMPTOM A: BRAKES PULL TO ONE SIDE

SYMPTOM A: BRAKES PULL TO ONE SIDE

SYMPTOM B: BRAKES EXCESSIVELY HOT WHILE DRIVING

SYMPTOM B: BRAKES EXCESSIVELY HOT WHILE DRIVING

SYMPTOM C: POOR BRAKING EFFECT

SYMPTOM C: POOR BRAKING EFFECT

SYMPTOM D: BRAKE PEDAL MOTION TOO SOFT & SPONGY

SYMPTOM D: BRAKE PEDAL MOTION TOO SOFT & SPONGY

SYMPTOM E: BRAKE PEDAL TRAVEL EXCESSIVE

SYMPTOM E: BRAKE PEDAL TRAVEL EXCESSIVE

SYMPTOM F: UNEVEN PAD WEAR

SYMPTOM F: UNEVEN PAD WEAR

SYMPTOM G: BRAKE PADS WORN AT ANGLE

SYMPTOM G: BRAKE PADS WORN AT ANGLE

SYMPTOM H: SEIZED BRAKE PADS

SYMPTOM H: SEIZED BRAKE PADS

SYMPTOM I: BRAKES SQUEAL OR RATTLE

SYMPTOM I: BRAKES SQUEAL OR RATTLE

SYMPTOM J: BRAKE PEDAL DEAD TRAVEL EXCESSIVE

SYMPTOM J: BRAKE PEDAL DEAD TRAVEL EXCESSIVE

SYMPTOM K: JAMMED PISTON IN BRAKE CALIPER

SYMPTOM K: JAMMED PISTON IN BRAKE CALIPER

SYMPTOM L: PULSATING EFFECT ON BRAKE PEDAL

SYMPTOM L: PULSATING EFFECT ON BRAKE PEDAL

SYMPTOM M: PARKING BRAKE EFFECT INSUFFICIENT

SYMPTOM M: PARKING BRAKE EFFECT INSUFFICIENT

Low Pressure Test

1. Remove heater bulkhead. See «HEATER BULKHEAD»(/bmw/x3/e83-2003-2006/remont/mechanical-hydraulic/#disc-x3__heater-bulkhead).
2. Pull hose off connection. Install Vacuum Tester (34 3 100) between connection and vacuum hose on non-return valve. (Scheme 4)
3. Start engine and check buildup of partial vacuum. Stop engine.
4. Press brake pedal to set a partial vacuum of no more than 11.6 psi (.8 bar) and wait for value to stabilize.
5. When the brake pedal is not pressed, the partial vacuum is allowed to drop by maximum.8 psi (.06 bar) over a test period of one minute.

If specified values are not reached

1. Check line connections for vacuum seal.
2. Replace vacuum non-return valve.
3. Check seal between brake booster and brake master cylinder (sealing ring) for perfect condition and correct seating.
4. If the specified values are not achieved when the test is repeated, you must replace the brake booster.
5. After removing tester, reinstall heater bulkhead. See «HEATER BULKHEAD»(/bmw/x3/e83-2003-2006/remont/mechanical-hydraulic/#disc-x3__heater-bulkhead) .

Scheme 4

1. At the first tooth, no braking effect should be present.
2. At the 2nd tooth, braking action can begin and the indicator light may be lit.
3. At the 3rd, tooth, braking action must begin and the indicator light must be lit.
4. At the 4th tooth, braking action increases.
5. At the 5th tooth, wheel circumferential force must be at least 247 pound-force (1100 N) at one of the two rear wheels, and at least 225 pound-force (1000 N) at the other wheel. Wheel circumferential force differential (left to right) maximum 30 percent from highest value (shortly before wheel lockup). A readjustment must be carried out in event of larger deviations of wheel circumferential force. See «PARKING BRAKE»(/bmw/x3/e83-2003-2006/remont/mechanical-hydraulic/#disc-x3__parking-brake) under ADJUSTMENTS.
6. Braking with locked wheels must be possible with the parking brake.
7. The ABS/ASC warning lights, if on, will automatically switch off by switching off engine, waiting at least 30 seconds, restart engine and drive away. Warning lights will go out when speed exceeds 8 MPH. (Fault codes will be retained in memory.)
8. The parking brake must be readjusted whenever the actuation stroke is greater than 10 teeth.

SERVICE BRAKE

Note. High-pressure and low-pressure tests (leakage test) must be performed with the engine switched off.

High-Pressure Test

Note. Perform test on both brake circuits, front and rear.

1. Unscrew bleeder screw, connect pressure tester and bleed. (Scheme 5)
2. Load brake pedal with a force of approximately 112 lbs. (500 N), and block pedal with pedal support. Line pressure should be approximately 479 psi (33 bar).
3. After 2 minutes, pressure must not drop by more than 8 percent.
4. Perform low-pressure test.

Note. Perform test on both brake circuits, front and rear.

1. Reset pedal support until line pressure in brake system is equal to 30-72 psi (2-5 bar). Car and measuring equipment must remain perfectly still as vibrations will distort the result.
2. Pressure should remain constant during five minute test.
3. Check all rubber parts in case of excessive pressure drop.
4. Bleed brake calipers and wheel brake cylinders after finishing test. See «BLEEDING BRAKE SYSTEM»(/bmw/x3/e83-2003-2006/remont/mechanical-hydraulic/#disc-x3) .

Scheme 5

THICKNESS OF BRAKE LINING

Note. The thickness of the outer brake linings can be determined without removing the wheels.

1. If necessary, move car until opening for brake lining wear indicator (brake lining) can be seen through rim styling.
2. Insert Special Tool (34 1 260) through rim into opening for brake lining wear indicator.
3. Press special tool onto brake lining. Slide ring (1) in direction of arrow as far as it will go and read off measured value. (Scheme 6)
4. Minimum thickness for all models is stamped in brake disc shell. Wear warning from residual lining thickness is.12" (3 mm). Maximum machining limit per friction ring side is.03" (.8 mm). For minimum thickness see «BRAKE LINING MINIMUM THICKNESS»(/bmw/x3/e83-2003-2006/remont/mechanical-hydraulic/#disc-x3) table.

BRAKE LINING MINIMUM THICKNESS

Scheme 6

BRAKE BOOSTER

Note. Numbers in text refer to numbers in figures.

Removal

1. Remove master cylinder. See «MASTER CYLINDER»(/bmw/x3/e83-2003-2006/remont/mechanical-hydraulic/#disc-x3__master-brake-cylinder).
2. Remove screws (1) for pedal assembly trim. (Scheme 7) Unclip trim for pedal assembly (4) at retaining points (2). Remove rotary clip (3) and pull back trim for pedal assembly (4) in direction of arrow.
3. Disconnect plug connections and remove trim for pedal assembly.
4. Detach locking clip (1) from brake pedal. (Scheme 8) Disengage and pull out locking pin. Unscrew nuts (2).
5. Carefully pull brake booster out of bulkhead and tilt out. (Scheme 9)
6. Tilt microfilter housing cover (2) upwards and lift out brake booster (1) in direction of arrow. (Scheme 10)

Scheme 7

Scheme 8

Scheme 9

Scheme 10

Installation

1. To install, reverse removal procedure. Carefully insert brake booster unit into place.
2. Replace self-locking nuts and tighten to specification. See «TORQUE SPECIFICATIONS»(/bmw/x3/e83-2003-2006/remont/mechanical-hydraulic/#disc-x3__torque-specifications).
3. Locator tabs (1) of trim for pedal assembly (2) must not be damaged. (Scheme 11)

Scheme 11

BRAKE BOOSTER NON-RETURN VALVE

Note. If a rubber vacuum hose is fitted, it can be replaced individually. If a plastic vacuum line is fitted, it can only be replaced as a single unit together with non-return valve.

Note. Numbers in text refer to numbers in figures.

Removal & Installation

1. Press brake pedal several times to reduce vacuum in brake booster, making it easier to pull off vacuum hose.
2. Remove heater bulkhead. See «HEATER BULKHEAD»(/bmw/x3/e83-2003-2006/remont/mechanical-hydraulic/#disc-x3__heater-bulkhead).
3. Release clip (1) and detach vacuum hose (2) from non-return valve (3). (Scheme 12) Remove non-return valve (3) from brake booster.
4. To install, reverse removal procedure. Replace hose clip. Check sealing ring in brake booster and replace, if necessary.

Scheme 12

BRAKE BOOSTER VACUUM HOSE

Note. Numbers in text refer to numbers in figures.

1. Switch off ignition. Remove top section of intake filter. Remove screws. Remove intake filter housing (1). (Scheme 13)
2. Remove non-return valve. See «BRAKE BOOSTER NON-RETURN VALVE»(/bmw/x3/e83-2003-2006/remont/mechanical-hydraulic/#disc-x3__brake-booster-non-return-valve).
3. Disconnect wiring harness (1) from compartment partition wall (3) and set toward rear. (Scheme 14) Turn rotary catches (1) through 90 degrees and remove compartment partition wall (3).
4. Release hose clip (1) and remove vacuum hose (2). (Scheme 15)
5. To install, reverse removal procedure. Replace hose clips. Make sure trim panel is correctly seated in lower guides. Install guide rail (1) on intake filter housing on rubber mount (2). (Scheme 16)

Scheme 13

Scheme 14

Scheme 15

Scheme 16

BRAKE DISCS

1. Raise and support vehicle. Remove wheel(s).
2. If necessary, remove and clean disc pads. See «BRAKE DISC PADS»(/bmw/x3/e83-2003-2006/remont/mechanical-hydraulic/#disc-x3__brake-disc-pads).
3. Remove caliper mounting bolts and raise caliper off mounting assembly and suspend from vehicle with wire. Brake hose remains connected.
4. Unscrew bolts and take off brake disc. (Scheme 17)

Scheme 17

1. Thoroughly clean contact surface of brake disc at wheel hub. Remove traces of corrosion if necessary. Unevenness on contact surface may result in distortion of brake disc.
2. Install brake disc and tighten bolts to specification. See «TORQUE SPECIFICATIONS»(/bmw/x3/e83-2003-2006/remont/mechanical-hydraulic/#disc-x3__torque-specifications) .
3. If removed, install brake pads.
4. Check that brake hose has not been disconnected. If disconnected, make sure it is positively attached.
5. Replace caliper and tighten screws to specification. See «TORQUE SPECIFICATIONS»(/bmw/x3/e83-2003-2006/remont/mechanical-hydraulic/#disc-x3__torque-specifications) .
6. Install wheels. Tighten wheel lug bolts to specification. See «TORQUE SPECIFICATIONS»(/bmw/x3/e83-2003-2006/remont/mechanical-hydraulic/#disc-x3__torque-specifications) . Bleed brakes if brake hose was disconnected.
7. If work was on rear brakes, adjust parking brake. See «PARKING BRAKE»(/bmw/x3/e83-2003-2006/remont/mechanical-hydraulic/#disc-x3__parking-brake) under ADJUSTMENTS.

BRAKE DISC PADS

Note. Numbers in text refer to numbers in figures.

1. Raise and support vehicle. Remove wheel(s).
2. On front wheels, lift out retaining spring (1). (Scheme 18)
3. On left front side, disconnect plug connection for brake lining wear indicator. On right rear side, disconnect plug connection for brake pad sensor.
4. On all sides, remove plastic plugs (2). (Scheme 19)
5. Release guide screws (1). (Scheme 20) On rear wheel, lift out retaining spring. On all wheels, withdraw brake caliper backwards. Do NOT allow brake caliper to hang from brake hose.
6. Turn piston fully back with Special Tool (34 1 050). (Scheme 21)
7. Remove outer brake pad. Inner brake pad is located with its spring in the piston.
8. Mark any worn brake pads. In the event of one-sided brake lining wear, do not change brake pads around.

Scheme 18

Scheme 19

Scheme 20

Scheme 21

1. Check threads. Replace all guide screws which are not in perfect condition.
2. New brake linings may only be installed if brake disc thickness is greater than or equal to minimum thickness. See «BRAKES - TECHNICAL DATA»(/bmw/x3/e83-2003-2006/remont/mechanical-hydraulic/#brakes-technical-data).
3. Clean brake pads.
4. Do not apply grease to brake pad backplate.
5. Check dust sleeve (1) for damage and replace if necessary. Clean contact face (2) of brake piston and apply a thin coating of anti-squeak compound. (Scheme 22)
6. Clean contact faces (1,2) of brake pad hammer heads/brake caliper housing and coat with anti-squeak compound. (Scheme 23)
7. Grease contact surfaces on brake caliper at top and bottom.
8. Clean contact face (3) of brake caliper and apply a thin coating of anti-squeak compound. (Scheme 24)
9. Clean contact face of brake caliper mounting bracket and apply a thin coating of anti-squeak compound.
10. Piston side front brake pads are directional. Install brake pad with identification mark "L" on left and "R" on right side of vehicle.
11. Use only clean guide screws to install caliper. Do not grease. Tighten to specification. See «TORQUE SPECIFICATIONS»(/bmw/x3/e83-2003-2006/remont/mechanical-hydraulic/#disc-x3__torque-specifications).
12. Make sure brake hose is positively attached in mounting fixture.
13. Install plastic plugs.
14. Connect plug connection for brake pad wear indicator in front and pad sensor in rear.
15. Fully depress brake pedal several times so that brake pads contact brake discs.
16. Bring brake fluid level up to MAX marking.

Scheme 22

Scheme 23

Scheme 24

BRAKE EXPANSION TANK

Note. Numbers in text refer to numbers in figures.

1. Switch off ignition. Remove heater bulkhead. See «HEATER BULKHEAD»(/bmw/x3/e83-2003-2006/remont/mechanical-hydraulic/#disc-x3__heater-bulkhead).
2. Remove top section of intake filter. Unfasten screws. (Scheme 13) Remove intake filter housing (1).
3. Remove non-return valve from brake booster. See «BRAKE BOOSTER NON-RETURN VALVE»(/bmw/x3/e83-2003-2006/remont/mechanical-hydraulic/#disc-x3__brake-booster-non-return-valve).
4. Disconnect wiring harness (1) from units compartment partition wall (3) and place toward rear. (Scheme 14) Turn rotary catches (1) past 90 degrees and remove compartment partition wall (3).
5. Suck brake fluid out of expansion tank. Use a suction device used exclusively for drawing off brake fluid.
6. Unfasten plug connection (1) and disconnect. (Scheme 25) Pull off supply hose (2) of clutch hydraulic system, if necessary. Release retaining screw (3). Pull expansion tank (4) vertically out of brake master cylinder.
7. To install, reverse removal procedure. Check rubber plug in master brake cylinder. No damage may be present.
8. Push the expansion tank vertically onto the master brake cylinder.
9. Tighten release screw to specification. See «TORQUE SPECIFICATIONS»(/bmw/x3/e83-2003-2006/remont/mechanical-hydraulic/#disc-x3__torque-specifications).
10. Make sure trim panel is correctly seated in lower guides. Install guide rail (1) for intake filter housing on rubber mount (2). (Scheme 16)
11. Bleed brake system. See «BLEEDING BRAKE SYSTEM»(/bmw/x3/e83-2003-2006/remont/mechanical-hydraulic/#disc-x3).

Scheme 25

BRAKE HOSES

Note. Numbers in text refer to numbers in figures.

Removal & Installation (Front)

1. Remove wheel.
2. Apply pedal prop and depress brake pedal slightly. This prevents brake fluid from emerging from expansion tank when brake lines are opened.
3. Disconnect brake hose from brake line (1). (Scheme 26) Remove retaining clip (2) and pull brake hose out of holder. Detach brake hose (3) from brake caliper.
4. To install, reverse removal procedure. Move wheels into straight ahead position. Insert brake hose in bracket and screw onto brake pipe. Fit retaining clip. Tighten brake hose on brake caliper to specification. See «TORQUE SPECIFICATIONS»(/bmw/x3/e83-2003-2006/remont/mechanical-hydraulic/#disc-x3__torque-specifications).
5. Make sure retaining clip is correctly fitted. Tighten brake hose to brake line to specification. See «TORQUE SPECIFICATIONS»(/bmw/x3/e83-2003-2006/remont/mechanical-hydraulic/#disc-x3__torque-specifications).
6. Install wheel and tighten wheel lug bolts to specification. See «TORQUE SPECIFICATIONS»(/bmw/x3/e83-2003-2006/remont/mechanical-hydraulic/#disc-x3__torque-specifications).
7. Bleed brake system. See «BLEEDING BRAKE SYSTEM»(/bmw/x3/e83-2003-2006/remont/mechanical-hydraulic/#disc-x3).

Scheme 26

Removal & Installation (Rear)

1. Apply pedal prop and depress brake pedal slightly. This prevents brake fluid from emerging from expansion tank and air from entering system when brake lines are opened.
2. Disconnect brake hose (2) from brake line (1). (Scheme 27)
3. Detach retaining plate (1) from metal bracket and feed out brake hose (2). (Scheme 28) Disconnect brake hose (2) from brake caliper.
4. To install, reverse removal procedure. Tighten brake hose on brake caliper to specification. See «TORQUE SPECIFICATIONS»(/bmw/x3/e83-2003-2006/remont/mechanical-hydraulic/#disc-x3__torque-specifications). Insert brake hose in bracket and screw onto brake pipe. Fit retaining plate (1). (Scheme 28)
5. Grip brake hose at square (3) to prevent piece from turning in retaining bracket. (Scheme 27) Tighten brake hose (2) to brake line (1) to specification. See «TORQUE SPECIFICATIONS»(/bmw/x3/e83-2003-2006/remont/mechanical-hydraulic/#disc-x3__torque-specifications).
6. Bleed brake system. See «BLEEDING BRAKE SYSTEM»(/bmw/x3/e83-2003-2006/remont/mechanical-hydraulic/#disc-x3).

Scheme 27

Scheme 28

BRAKE LIGHT SWITCH

No information is available from manufacturer at time of publication.

BRAKE LINES

New Brake Line Precautions

1. Protective coating on brake lines must not be damaged while bending.
2. Brake lines must not be bent back and forth.
3. Watch distances to fixed and moveable vehicle parts. Brake lines must not contact or rub.
4. Tighten brake line couplings with torque wrench to specifications. See «TORQUE SPECIFICATIONS»(/bmw/x3/e83-2003-2006/remont/mechanical-hydraulic/#disc-x3__torque-specifications) .

1. Apply pedal prop and depress brake pedal slightly. This prevents brake fluid from flowing out of expansion tank and into brake system when brake lines are opened.
2. Disconnect brake hose from line.
3. Bend new pipe as required using Bending Tool (34 5 100). Removed pipe can be used as template.
4. If replacing front brake pipe, move wheels into straight-ahead position. Install new pipe and tighten to specification. See «TORQUE SPECIFICATIONS»(/bmw/x3/e83-2003-2006/remont/mechanical-hydraulic/#disc-x3__torque-specifications) .
5. Remove pedal prop and bleed brake system. See «BLEEDING BRAKE SYSTEM»(/bmw/x3/e83-2003-2006/remont/mechanical-hydraulic/#disc-x3) .

CALIPER ASSEMBLY

Note. Numbers in text refer to numbers in figures.

1. Raise and support vehicle. Remove wheel(s).
2. Apply pedal support and press brake pedal slightly. This prevents brake fluid from emerging from expansion tank and air from entering the brake system after the brake lines have been detached.
3. Disconnect brake pipe from connection with brake hose.
4. On left remove connector for wear indicator.
5. Remove bolts (1). (Scheme 29) Remove brake caliper.
6. To install, reverse removal procedure. Set steering to straight ahead position. Screw brake hose to brake line. Make sure brake hose is not twisted. Tighten to specification, See «TORQUE SPECIFICATIONS»(/bmw/x3/e83-2003-2006/remont/mechanical-hydraulic/#disc-x3__torque-specifications).
7. Tighten brake hose to brake caliper to specification, See «TORQUE SPECIFICATIONS»(/bmw/x3/e83-2003-2006/remont/mechanical-hydraulic/#disc-x3__torque-specifications).
8. Bleed brake system. See «BLEEDING BRAKE SYSTEM»(/bmw/x3/e83-2003-2006/remont/mechanical-hydraulic/#disc-x3).
9. Install and tighten wheel bolts to specification. See «TORQUE SPECIFICATIONS»(/bmw/x3/e83-2003-2006/remont/mechanical-hydraulic/#disc-x3__torque-specifications).

Scheme 29

1. Raise and support vehicle. Remove wheel(s).
2. Apply pedal support and press brake pedal slightly. This prevents brake fluid from emerging from expansion tank and air from entering the brake system after the brake lines have been detached.
3. Remove screws (1). (Scheme 30) Disconnect brake hose (2). Unfasten brake hose on connection to brake line.
4. On right side, disconnect plug connection for brake lining sensor. Pull off caliper towards rear of vehicle.
5. To install, reverse removal procedure. Check routing and securing of brake pad wear sensor cable. Check for correct securing with tab of dust cap. Rubbing of cable on rim must be prevented.
6. Tighten brake hose on brake cover. Tighten to specification. See «TORQUE SPECIFICATIONS»(/bmw/x3/e83-2003-2006/remont/mechanical-hydraulic/#disc-x3__torque-specifications). Tighten connection on brake line to specification. See «TORQUE SPECIFICATIONS»(/bmw/x3/e83-2003-2006/remont/mechanical-hydraulic/#disc-x3__torque-specifications).
7. Tighten caliper mounting screws to specification. See «TORQUE SPECIFICATIONS»(/bmw/x3/e83-2003-2006/remont/mechanical-hydraulic/#disc-x3__torque-specifications).
8. Bleed hydraulic system. See «BLEEDING BRAKE SYSTEM»(/bmw/x3/e83-2003-2006/remont/mechanical-hydraulic/#disc-x3).
9. Install and tighten wheel bolt. See «TORQUE SPECIFICATIONS»(/bmw/x3/e83-2003-2006/remont/mechanical-hydraulic/#disc-x3__torque-specifications).

Scheme 30

EXHAUST SYSTEM

Note. Removal of exhaust system must be carried out with the assistance of a second person.

Note. Numbers in text refer to numbers in figures.

1. Support exhaust system with jack and Special Tool (31 2 220) and secure against falling out. (Scheme 31)
2. Pull off vacuum hose (1). (Scheme 32) Remove nuts.
3. Remove bolts. (Scheme 33)
4. Remove bolts (1). (Scheme 34) Remove complete exhaust system.
5. To install, reverse removal procedure. Replace bolts.

Scheme 31

Scheme 32

Scheme 33

Scheme 34

FRONT AXLE WHEEL BEARINGS

See appropriate FRONT article in SUSPENSION.

HEATER BULKHEAD

Note. Numbers in text refer to numbers in figures.

1. Turn toggle (1) through 90 degrees and remove microfilter cover (2) towards front. (Scheme 35) Remove microfilter element.
2. Unclip retainers (1) and feed cable out of cable duct. (Scheme 36) Remove screws and remove microfilter housing towards front.
3. Detach rubber strip (1). (Scheme 37) Release locks (2) and pull side trim forwards a little.
4. Remove screws (1) and (2). (Scheme 38) Lift out heater bulkhead.
5. To install, reverse removal procedure. Seals on microfilter housing must not be damaged or missing.

Scheme 35

Scheme 36

Scheme 37

Scheme 38

MASTER BRAKE CYLINDER

Note. Numbers in text refer to numbers in figures.

1. Remove brake fluid expansion tank. See «BRAKE EXPANSION TANK»(/bmw/x3/e83-2003-2006/remont/mechanical-hydraulic/#disc-x3__brake-expansion-tank).
2. Disconnect brake lines (1) from master cylinder. (Scheme 39) Release nuts (2) and pull master cylinder (3) in direction of arrow straight out of brake booster.
3. To install, reverse removal procedure. Replace "O" ring (1). (Scheme 40) Replace self-locking nuts and tighten to specification. See «TORQUE SPECIFICATIONS»(/bmw/x3/e83-2003-2006/remont/mechanical-hydraulic/#disc-x3__torque-specifications).
4. Bleed brake system. See «BLEEDING BRAKE SYSTEM»(/bmw/x3/e83-2003-2006/remont/mechanical-hydraulic/#disc-x3).

Scheme 39

Scheme 40

PARKING BRAKE BOWDEN CABLES

Note. Numbers in text refer to numbers in figures.

1. Remove storage compartment. See «STORAGE COMPARTMENT»(/bmw/x3/e83-2003-2006/remont/mechanical-hydraulic/#disc-x3__storage-compartment).
2. Remove rear brake discs. See «BRAKE DISCS»(/bmw/x3/e83-2003-2006/remont/mechanical-hydraulic/#disc-x3__brake-discs).
3. Remove exhaust system. See «EXHAUST SYSTEM»(/bmw/x3/e83-2003-2006/remont/mechanical-hydraulic/#disc-x3__exhaust-system).
4. Remove heat shield.
5. Using Special Tool (32 1 030), press stop (1) of adjusting spring back until retaining hook (2) engages in stop (1). (Scheme 1) This will lock adjuster unit (ASZE).
6. Unclip mounting clip (1) upwards out of balance arm (2). (Scheme 41)
7. Guide parking brake Bowden cables (1) with a screwdriver inwards and pull out of balance bar (2). (Scheme 42)
8. Disconnect parking brake Bowden cables at expander locks. Release screw (1) and remove holder. (Scheme 43) Pull parking brake Bowden cables (2) out of wheel carrier.
9. Disconnect parking brake Bowden cables (1) from mountings (2). (Scheme 44) Pull parking brake Bowden cables (1) out of guide (3). Feed parking brake Bowden cables (1) out of guide of rear axle (4).
10. To install, reverse removal procedure.
11. Adjust parking brake. See «PARKING BRAKE»(/bmw/x3/e83-2003-2006/remont/mechanical-hydraulic/#disc-x3__parking-brake) under ADJUSTMENTS.

Scheme 41

Scheme 42

Scheme 43

Scheme 44

PARKING BRAKE LEVER

Note. Parking brake lever and adjustment unit (ASZE) are only replaced completely as a single unit.

Note. Numbers in text refer to numbers in figures.

1. Remove storage compartment. See «STORAGE COMPARTMENT»(/bmw/x3/e83-2003-2006/remont/mechanical-hydraulic/#disc-x3__storage-compartment).
2. Using Special Tool (32 1 030), unlock adjuster unit (ASZE) by pressing stop (1) of adjusting spring back so that retaining hook (2) engages in stop (1). (Scheme 1)
3. Release nuts (1) and remove carrier for center console (2). (Scheme 45)
4. Disconnect plug connection (1) for Dynamic Stability Control (DSC) sensor. (Scheme 46) Remove screws (2) and remove holder with DSC sensor.
5. Unclip mounting clip (1) upwards out of balance arm (2). (Scheme 41)
6. Guide handbrake Bowden cables (1) with a screwdriver inwards and pull out of balance bar (2). (Scheme 42)
7. Disconnect cable (1) from handbrake check switch. (Scheme 47) Remove screw (2) and remove parking brake lever (3).

Scheme 45

Scheme 46

Scheme 47

1. To install, reverse removal procedure. Tighten screw for parking brake lever to specification. See «TORQUE SPECIFICATIONS»(/bmw/x3/e83-2003-2006/remont/mechanical-hydraulic/#disc-x3__torque-specifications) .
2. Tighten screw for DSC sensor to specification. See «TORQUE SPECIFICATIONS»(/bmw/x3/e83-2003-2006/remont/mechanical-hydraulic/#disc-x3__torque-specifications) .
3. Adjust parking brake. See «PARKING BRAKE»(/bmw/x3/e83-2003-2006/remont/mechanical-hydraulic/#disc-x3__parking-brake) under ADJUSTMENTS.

PARKING BRAKE SHOES

Note. Some illustrations show right side. Left side is mirror image.

Note. Numbers in text refer to numbers in figures.

1. Raise and support vehicle. Remove rear wheel(s).
2. Remove rear brake disc. See «BRAKE DISCS»(/bmw/x3/e83-2003-2006/remont/mechanical-hydraulic/#disc-x3__brake-discs).
3. Using Special Tool (32 1 030), press stop (1) of adjusting spring back until retaining hook (2) engages in stop (1). (Scheme 1) This will lock adjuster unit (ASZE).
4. Disconnect return spring (1) with brake spring pliers. (Scheme 48)
5. Disconnect return spring (1) with brake spring pliers. (Scheme 49)
6. Twist clamping pins (1) with Special Tool (34 4 000) through 90 degrees and disconnect. (Scheme 50) Remove parking brake shoes.
7. To install, reverse removal procedure. Coat threads of adjusting screw (2) with grease. Notice installation position of adjusting screws. (Scheme 48)
8. Check return springs and replace if necessary.
9. Adjust parking brake and check operation. See «PARKING BRAKE»(/bmw/x3/e83-2003-2006/remont/mechanical-hydraulic/#disc-x3__parking-brake) under ADJUSTMENTS.

Scheme 48

Scheme 49

Scheme 50

REAR AXLE WHEEL BEARINGS

Note. Numbers in text refer to numbers in figures.

1. Remove axle shaft. See «AXLE SHAFTS (REAR)»(/bmw/x3/e83-2003-2006/remont/axle-shafts/#axle-shafts-repair__axle-shafts-rear) in AXLE SHAFTS article.
2. Remove brake disc. See «BRAKE DISCS»(/bmw/x3/e83-2003-2006/remont/mechanical-hydraulic/#disc-x3__brake-discs).
3. Remove lip for wheel speed sensor. Open plug housing (1). (Scheme 51) Pull plug connection for wheel speed sensor out of fixture and disconnect.
4. Remove cable holder along trailing. Remove hexagon socket screw (1). (Scheme 52) Withdraw wheel speed sensor (2) from bore hole.
5. Screw Special Tool (33 2 116) onto drive flange with 5 wheel studs. (Scheme 53) Drive out drive flange with Special Tools (33 4 201/202/203).
6. Remove inner wheel bearing race with the following procedure: Detach wheel bearing inner race with Special Tool (33 4 400) through groove in bearing inner race. According to outside diameter of bearing inner race, use Special Tool (33 4 401). (Scheme 54) To determine additional Special Tool, see «REMOVING INNER WHEEL BEARING RACE»(/bmw/x3/e83-2003-2006/remont/mechanical-hydraulic/#disc-x3). Tension Special Tool (33 4 401) with Wenches (33 4 403) and (33 4 404) until it can still just be turned in groove. (Scheme 55) Screw in Special Tool (33 4 402). Detach inner bearing race.
7. Press retaining ring (1) together using pliers and remove. (Scheme 56)
8. Remove wheel bearing with Special Tools (33 3 261/262/265). (Scheme 57)

REMOVING INNER WHEEL BEARING RACE

Scheme 51

Scheme 52

Scheme 53

Scheme 54

Scheme 55

Scheme 56

Scheme 57

1. To install, reverse removal procedure. Check installation position of wheel bearing. Correct, if necessary.
2. Install new wheel bearing (1) with Special Tools (33 3 261/264/265). (Scheme 58)
3. Check seating of retaining ring (1). (Scheme 56) Correct, if necessary. Install retaining ring.
4. Install drive flange using Special Tools (33 4 041/ 042/ 043/ 045/ 048). (Scheme 59)
5. Clean bore hole for wheel speed sensor and grease with lubricating grease (Staburags NBU 12/K or equivalent). Tighten hexagon socket screw to specification. See «TORQUE SPECIFICATIONS»(/bmw/x3/e83-2003-2006/remont/mechanical-hydraulic/#disc-x3__torque-specifications).
6. Install brake disc.
7. Install rear axle shaft. See «AXLE SHAFTS (REAR)»(/bmw/x3/e83-2003-2006/remont/axle-shafts/#axle-shafts-repair__axle-shafts-rear) in AXLE SHAFTS article.

Scheme 58

Scheme 59

STORAGE COMPARTMENT

Note. Numbers in text refer to numbers in figures.

1. Open cover for center armrest. Lift out storage compartment. If equipped with built-in telephone console, disconnect plug connection (1). (Scheme 60) Release protective sleeve (2) and disconnect plug connection underneath.
2. Remove screws (1). (Scheme 61) Remove cover (2) towards top.
3. If necessary, remove trim for gearshift lever. See «TRIM FOR GEARSHIFT LEVER»(/bmw/x3/e83-2003-2006/remont/mechanical-hydraulic/#disc-x3__trim-for-gearshift-lever).
4. Disconnect plug connection (1). (Scheme 62) Unclip catches (2) on housing for cigarette lighter (3). Remove housing (3) in direction of arrow.
5. Remove nuts (1) and screws (2) on rear storage compartment. (Scheme 63)
6. Lever out boot (1) with Special Tool (00 9 317). (Scheme 64)
7. Unclip trim (1) with Special Tool (00 9 317) in lower area only. (Scheme 65)
8. Remove screws (1) on trim (2). (Scheme 66)
9. Lever out metal tabs (1) in direction of arrow and remove. (Scheme 67)
10. Remove screws (1) and slightly pull off trim (2) in direction of arrow towards front. (Scheme 68)
11. Disconnect plug connection (1) and, if necessary, plug connection (2). (Scheme 69) Feed trim (3) out of boot.
12. Unclip catches (1) on boot (2) with Special Tool (00 9 317). (Scheme 70) Pull off boot (2) towards top.
13. Remove screws (1) and (2). (Scheme 71) Feed out storage compartment (3) past boot (4) and remove towards top rear.
14. To install, reverse removal procedure. Catches must not be damaged.

Scheme 60

Scheme 61

Scheme 62

Scheme 63

Scheme 64

Scheme 65

Scheme 66

Scheme 67

Scheme 68

Scheme 69

Scheme 70

Scheme 71

TRIM FOR GEARSHIFT LEVER

Note. Illustrations show removal of trim for automatic transmission. Procedure for standard transmission is virtually identical. Numbers in text refer to numbers in figures.

Note. To remove trim, it is not absolutely necessary to remove selector lever knob. However, removing knob does make it easier to remove gearshift lever trim.

1. Apply parking brake. Place transmission in neutral.
2. Pull off gearshift lever knob (1) with a forceful jerk. (Scheme 72) Do NOT twist knob when removing. There is a danger of shearing off turning lock. Press sides of lever cover (2) together and feed out towards top. Unclip trim (3) for gearshift lever towards top. Disconnect associated plug connections and remove trim for gearshift lever towards top.
3. To install, reverse removal procedure. Make sure retainers are correctly seated in appropriate mounts of trim for gearshift lever.

Scheme 72

BRAKE CALIPER

Note. Numbers in text refer to numbers in figures.

Disassembly

1. Remove caliper. See «CALIPER ASSEMBLY»(/bmw/x3/e83-2003-2006/remont/mechanical-hydraulic/#disc-x3__caliper-assembly) under REMOVAL & INSTALLATION.
2. Remove plastic caps (1). (Scheme 73) Unscrew guide bolts (2).
3. Dismantle brake caliper and remove brake linings.
4. Slowly apply air pressure to fluid inlet of caliper to force out piston. To protect piston, place a protective plate (hard wood or hard felt) in caliper recess. (Scheme 74) Do NOT grip piston with fingers as there is a risk of trapping.
5. Check guide sleeves (5). Fit new repair-kit guide sleeve if necessary. (Scheme 75)
6. Remove sealing ring carefully with a plastic needle. (Scheme 76)
7. Thoroughly inspect cylinder bore, piston and flange surfaces. Clean cylinder bores and parts with alcohol and dry with compressed air. Machining of cylinders and pistons is not permitted.

Scheme 73

Scheme 74

Scheme 75

Scheme 76

1. Coat cylinder bore, piston, and sealing sleeve with a light coat of brake cylinder paste. (Scheme 77)
2. Install dust sleeve in front annular groove and press into annular groove over entire diameter. (Scheme 78)
3. The area between dust cover and brake caliper housing must be kept dry so as to ensure correct seating for dust cover. Keep brake cylinder paste or brake fluid away from this area to ensure dust sleeve is perfectly seated.
4. Take up brake piston with a commercially available extension and socket and gently press onto dust sleeve. (Scheme 79) Blow up sleeve with compressed air to a maximum 44 psi (3 bar). Sleeve jumps over brake piston.
5. Press brake lining fully outwards and insert spring (4). (Scheme 80)
6. Only clean guide screws, do not grease. Check and replace if necessary. Tighten to specification. See «TORQUE SPECIFICATIONS»(/bmw/x3/e83-2003-2006/remont/mechanical-hydraulic/#disc-x3__torque-specifications).
7. Install caliper. See «CALIPER ASSEMBLY»(/bmw/x3/e83-2003-2006/remont/mechanical-hydraulic/#disc-x3__caliper-assembly).

Scheme 77

Scheme 78

Scheme 79

Scheme 80

TORQUE SPECIFICATIONS

TORQUE SPECIFICATIONS

BRAKE SPECIFICATIONS

For disc brake specifications, see BRAKES - TECHNICAL DATA .

Scheme 81

Scheme 82

Scheme 83

Scheme 84

Scheme 85

Scheme 86

Scheme 87

Scheme 88

Scheme 89

Scheme 90

Scheme 91

Scheme 92

Scheme 93

See also:
• BRAKES - TECHNICAL DATA
• AXLE SHAFTS (REAR)
• FLUSHING BRAKE SYSTEM COMPLETELY
• BLEEDING FRONT OR REAR-AXLE BRAKE CIRCUIT
• TORQUE SPECIFICATIONS
• SYMPTOM INDEX
• A
• B
• C
• D
• E
• F
• G
• H
• I
• J
• K
• L
• M
• HEATER BULKHEAD
• PARKING BRAKE
• MASTER CYLINDER
• BRAKE BOOSTER NON-RETURN VALVE
• BRAKE DISC PADS
• BRAKE EXPANSION TANK
• STORAGE COMPARTMENT
• BRAKE DISCS
• EXHAUST SYSTEM
• TRIM FOR GEARSHIFT LEVER
• CALIPER ASSEMBLY