SD-23-7550 ® AIR DISC BRAKE (SB-6™ and SB-7™) SUPPLY PORT ACTUATOR ROD RETURN SPRINGS OUTER BRAKE PAD ROTOR LEVER ACTUATING BEAM ECCENTRIC BEARING INNER BRAKE PAD AXIAL RADIAL FIGURE 1 - BENDIX AIR DISC BRAKE 1
Index Page 1 1.1 1.2 1.2.1 1.3 1.4 1.4.1 1.5 Exploded view of brake Axial Disc Brake Components Axial Disc Brake Repair Kits Axial Disc Brake Wear Indicator Kits Radial Disc Brake Components Radial Disc Brake Repair Kits Radial Disc Brake Wear Indicator Kits Brake Disc Rotor 4 5 5 6 7 7 8 2 2.1 2.2 2.3 2.4 General information (for “Axial- and Radial Disc Brake”) Service Tools Diagnostic Equipment Lubrication Torque requirements 9 9 9 9 3 3.1 3.2 3.2.1 3.2.2 3.2.3 3.3 3.4 3.4.1 3.4.2 3.4.
9 9.1 9.2 10 10.1 10.2 10.2.1 10.2.2 Guide Pin Bushing replacement (for “Axial- and Radial Disc Brake”) Brass Bushing replacement Rubber Bushing replacement 28 28 28 Caliper replacement (for “Axial- and Radial Disc Brake”) Caliper removal Caliper fitting Caliper with Rubber Boot (10) Caliper with Steel Cap (10a) 29 30 30 31 11 Carrier replacement (for “Axial- and Radial Disc Brake”) 32 12 12.1 12.2 12.3 12.
1 Exploded views 1.1 Axial Disc Brake Components (for Wear Indicatators Kits see 1.2.
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1.3 Radial Disc Brake Components (for Wear Indicator Kits see 1.4.
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1.5 Brake Rotors (for “Axial- and Radial Disc Brake”) When replacing the Rotors, please also refer to the instructions provided by the Vehicle Manufacturer. They should also referred to when spec'ing Bendix Rotors. When replacing Rotors, please adhere to the recommended bolt tightening torques. The use of non-approved Brake Rotors will reduce levels of safety and invalidate warranty. Brake Rotors can be ordered through any authorized Bendix parts outlet. More information can be found on the internet at www.
2 General Information (for “Axial- and Radial Disc Brake”) 2.1 Service Tools Part Number Description ll 19252 Press-In Tool for Tappet and Boot (13) ll 19253 Pull-In Tool for Inner Boot (9) ll 19254 II 32202 Pull-In/Out Tool for Brass Bushing (7) Wedged Fork for removal of Tappet and Boot (13) II 36797 Grooving Tool for Brass Bushing (7) Z001105 Press in Tool for Steel Cap (10a) Service tool kit ZB 9032 II 37951/004EX contains the tools listed as well as this Service manual.
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3.2 Description of operation (Floating Caliper principle) 3.2.1 Brake actuation During actuation, the Push Rod of the Actuator (18/1 or 18/2) moves the Lever (19). The input forces are transferred via the Eccentric Bearing (20) to the Bridge (17). The force is then distributed by the Bridge (17) and the two Threaded Tubes (16) to the Tappets (13) and finally to the inboard Pad (12).
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3.4 Description of operation (Floating Caliper principle) 4 Safety Instructions for service work 3.4.1. Please refer to the relevant safety instructions for repair work on commercial vehicles, especially for jacking up and securing the vehicle. Brake Actuation During actuation, the Push Rod of the Actuator (18/1 or 18/2) moves the Lever (19). The input forces are transferred via the Eccentric Bearing (20) to the Bridge (17).
5 Brake Testing (for Axial- and Radial Disc Brake) 5.1 Fault finding procedure Air Disc Brake Lift vehicle, turn wheel by hand Does wheel turn smoothly? NO Residual pressure within the braking cylinder? NO Running clearance ok? (see section 5.2) NO YES YES Running clearance ok? (see section 5.2) Yes NO Check and if necessary, change or service preceding braking device Check adjuster (see section 5.
5.2 Adjuster check WARNING! Before starting repair work, block the wheels to ensure that the vehicle cannot roll away, before releasing the park brake. See Page 36 for full Safety Guidelines. 23 37 Remove wheel. The caliper assemply should be pushed inboard on its guide pins. Using a suitable tool, press the inboard pad (12) away from the Tappets and check Tappet and inboard pad backplate - it should be between 0.02in. (0.5mm) & 0.04in. (1.0mm).
5.3 Wear Limits of Pads and Rotors CAUTION! Stay within the Rotor and Pad Wear Limits Pads The thickness of the Pads must be checked regularly dependent on the usage of the vehicle. The Pads should be checked to adhere to any applicable legal requirements that may apply. If no Wear Indicator has been connected, check for wear at least every 3 months. If friction material is less than 0.08in. (2mm) (see E), the Pads must be replaced. C A B Rotors Measure thickness at the thinnest point.
A1 a At each change of Pads check the Rotors for grooves and cracks. The diagram at the right shows possible conditions of the surface. A1 = Small cracks spread over the surface are allowed B1 max. 0.75 x a max. 1.5 mm B1 = Cracks less than 0.06in. (1.5mm) deep or wide, running in a Radial direction, are allowed C1 = Grooves (circumferencial) less than 0.06in. (1.5mm) wide are allowed D1 C1 D1 = Cracks in the vanes are not allowed and the Rotor MUST BE REPLACED.
5.3.1 Brake Wear Check using Guide Pin (For all Axial and Radial Disc Brakes except those listed in Section 5.3.2 - These Callipers do not have the rib in position B (see also Section 5.3.2) 1 4 1 4 6 6 C B D M+P-KN-005 Pad conditions can be visually inspected without removing the road wheel by noting the positon of the Floating Pin (4) in the Caliper (1). If dimension ‘C’ is less than 0.04in. (1mm), a more accurate check of the Pads and Disc must be completed.
5.3.2 Brake Wear Check using Guide Pin (Only for Axial Disc Brakes SB 7541, SB 7551 to SB 7629, SB 7639 and Radial Disc Brakes SB 7102, SB 7112, SB 7103, SB 7113, SB 7104, SB 7114, SB 7105, SB 7115, SB 7108, SB7118, SB 7109, SB 7119, SB 7120, SB 7130 - These Callipers do have the rib in position B (see also Section 5.3.1) 1 1 4 6 4 6 B C D Pad conditions can be visually inspected without removing the road wheel by noting the positon of the Floating Pin (4) in the Caliper (1).
5.3.3 Wear Indicators There are two types of Pad Wear Indicators available to accommodate the differences in vehicle types and manufacturers, including: a) b) In - Pad Normally Closed Indicator - Circuit is broken when Pad Wear reaches the limit. In - Pad Normally Open Indicator - Circuit is made when Pad Wear reaches the limit. See Figure to the right. M+P-KN-007 c) Wear Indicator using built in Potentiometer.
5.4 Bendix Diagnostic Equipment The Bendix Diagnostic Unit ZB 9031 is a hand held device suitable for vehicles that are fitted with Bendix Air Disc Brakes using a continuous signal type of Wear Potentiometer. The wear condition of each brake can be measured by connecting the device to a suitable 13 pin socket (DIN 72570) where fitted. This socket must have been connected to each sensor by the vehicle manufacturer. The Diagnostic unit permits: Quick and simple wear check.
6 Pad replacement (for “Axial- and Radial Disc Brake”) WARNING! Before starting repair work, block the wheels to ensure that the vehicle cannot roll away, before releasing the park brake. See Page 36 for full Safety Guidelines. 6.1 Pad removal Take the wheel off (refer to Vehicle Manufacturer’s recommendations). Remove Clip (26) and Washer (45), push down the Pad Retainer (11) and remove Pin (44). If the Pad Retainer (11) is corroded, it should be replaced.
6.1.2 Caliper guidance check 31a*) Following Pad removal (Section 6.1) Using hand pressure only (no tools), the Caliper (1) must slide freely over the whole length of the Guide Pin arrangement > 1.2in. (30mm). During this operation the Sleeve (5) is sealed by the Boot (9) and Cap (10) or Steel Cap (10a) and O-Ring (31a). These must show no signs of damage. Check that these are correctly seated. 10a*) 9 5 7 10 The Caliper may have to be re-sealed by using a suitable Kit (see page 5 or page 7). 6.
The hub should turn easily by hand after having applied and released the brake. The Cap (37) must then be replaced after it has been lightly greased it with Renolit HLT2 (available as part number II14525). After setting the Pad Retainer (11) into the groove of the Caliper (1), it must be pushed in to allow the insertion of the Pad Retainer Pin (44). 44 Fit washer (45) and Spring Clip (26) to the Pad Retainer Pin (44) (use only new parts).
The Tappets (13) can be removed from the Threaded Tubes by using Wedge Fork A. (Order No. II32202). Remove the old Tappet Bush (116). A Check Inner Seal (arrow) and if damaged, replace the Caliper. 13 A 13 7.1.1 Adjuster thread inspection Place an new thickness Pad (12) into the outboard gap to avoid overrunning of the Threaded Tubes. 161 VF 00127/4 IMPORTANT! 12 Threaded Tubes should not be extended beyond thread engagement of the Bridge.
Using Tool B in reverse direction, the Tappet can be pressed on. B 13 With Caliper not installed on axle Grease threads with RENOLIT HLT2 (Order No. II14525). M+P-KN-022 Screw back Threaded Tubes (16), by turning the Adjuster (23) counter-clockwise. Sealing seat in the caliper for Tappet with Boot (13) must be clean and free of grease. B 13 Place new Tappet Bushing (161) onto the head of the Tube (16). Place Tappet with Boot (13) onto the head of the Tube.
8 Caliper Suspension sealing (Replacement of inner Boot (9) ) (for the Axial and Radial Disc Brake) Remove Caliper (see Section 10.1) Remove Ring (58) Pull out Sleeve (5) 5 Push out Boot (9) with screw driver. 9 Inspect and clean contact area of Boot (9) Put new Boot (9) into the Cup (arrow) of the Tool C (Order No II19253). 58 M+P-KN-025 9 9 C Position Sleeve with Boot (9) into the Caliper bore and pull in.
9 Guide Pin Bushing replacement (for “Axial- and Radial Disc Brake”) 7 D Remove Caliper (see Section 10.1) Remove Sleeve (5) and inner Boot (9) (see Section 8). 9.1 Brass Bushing (7) replacement Remove old Sleeve (5). Pull out Bushing (7) with Tool (D) (Order No. II19254). VF 00127/16 If Caliper has no groove (see arrow) (Note: Groove is always located on the inboard side) D Pull in new Brass Bush (7) with Tool (D). If Caliper has a groove: Pull in new Brass Bush (7) with Tool (D).
Deform new Rubber Bushing (6) and push from the inner side of the Caliper into the bore. Push Rubber Bushing (6) so that the outer positioning ring locates in the groove (see arrows). 6 IMPORTANT! Never use the white Grease (containing mineral oil) for lubricating the Bushing or Sleeve. Use only synthetic based green Grease (Part Number II32793). Improper Grease may cause the rubber Bushing to swell and prevent proper floatation.
WARNING! Hold the Caliper only on the exterior. Never insert your fingers between the Caliper and Carrier! Remove Caliper from Carrier. IMPORTANT! Opening or dismantling the Caliper is not permitted. Use only Genuine Bendix service Exchange Calipers. Disassembly of the Caliper will void any Warranty Claim. FD00114 10.2 Caliper fitting Check the Part No. on the label (arrow, Figure above right) to ensure that you have selected the proper replacement Caliper.
Tighten Rubber Boot Clip (31) Fit the Pads (see Section 6.2) Attach the Brake Chamber or Spring Brake (see Section 12.2 or 12.4) 39 31 31 M+P-KN-042 10.2.2 Caliper with Steelcap (10a) 10 IMPORTANT! Replace the Rubber Boot (10) by the Steel Cap (10a) when replacing the Sleeve (5), the O-Ring (31a) and the Screw (40) at the same time. Replace only on the recommendation of the Axle or Vehicle manufacturer. On SB 6... (19.5“) only permissible after manufacturing date A0026. (see type plate).
Assemply on the Caliper and Carrier removed from the axle: IMPORTANT! Replace the Rubber Boot (10) by the Steel Cap (10a) when replacing the Sleeve (5), the O-Ring (31a) and the Screw (40) at the same time. Replace only on the recommendation of the Axle or Vehicle manufacturer. On SB 6... (19.5“) only permissible after manufacturing date A0026. (see type plate). Put the Caliper on the Carrier.
12 Actuation cylinder replacement (for “Axial- and Radial Disc Brake”) 12.1 Brake Chamber removal Disconnect the air line from the Brake Chamber (18/2) Unscrew the Brake Chamber Mounting Nuts (do not re-use them). 18/2 Remove the Brake Chamber VF 00127/10 12.2 Brake Chamber fitting IMPORTANT: New Brake Chambers (18/2) have drain plugs installed. Remove the bottom plug (see arrows). All other drain holes should be plugged.
12.3 Spring Brake removal WARNING! Before starting repair work, block the wheels to ensure that the vehicle cannot roll away, before releasing the park brake. 18/1 See Page 36 for full Safety Guidelines. Release the parking brake, move the Hand Control Valve to the ‘run’ position. Screw-out Release Bolt (arrow) with a maximum torque of 26 ft. lbs. (35Nm). VF 00127/11 Release air from brake, move Hand Control Valve to ‘park’ position.
Attach the Actuator with new Nuts (self-locking EN ISO 7042) and torque tighten to +30 +22 133 ft.lbs. (180 Nm). Connect air hose, ensuring that hoses are correctly connected. Make sure that hoses are not twisted and that chafing is not possible. Push park control valve in to release parking brake, and check for leakage. Screw in Spring Brake Release bolt to maximum 52 ft.lbs. (70 Nm). IMPORTANT! Road test vehicle before returning to service.
13.4 General Safety Guidelines. WARNING! Please READ and follow these instructions to avoid personal injury or death: When working on or around a vehicle, the following general precautions should be observed at all times. 1. Park the vehicle on a level surface, apply the parking brakes, and always block the wheels. Always wear safety glasses. 2. Stop the engine and remove ignition key when working under or around the vehicle.
