front axle & suspension Overview Front Suspensions The Blue Bird All American is equipped with one of two front suspension systems: Hendrickson™ SofTek.™ The Softek front suspension is a three parabolic leaf spring configuration, and is standard equipment on the Forward Engine All American. Hendrickson™ AirTek.™ The Airtek front suspension is an air spring suspension used on the Forward Engine All Americans equipped with air suspension option. Two leveling valves maintain ride height at varying axle loads.
SERVICE MANUAL 36 A C B B D Right Side Shown Left Side Symetrical unless otherwise noted.
Front axle & suspension Torque Requirements description A Front Hanger Pivot B Shackle Bracket Pivot C Upper Shock D Lower Shock E Linkage Rod Assy Locknut F Leveling Valve Lockout G Axle Clamp Group Nuts H Air Spring Mounting Stud Locknuts (All) J Shackle Bracket Locknuts key torque +- 5% 300 ft.lbs. 300 ft.lbs. 125 ft.lbs. 125 ft.lbs. 11 ft.lbs. 8 ft.lbs. 295 ft.lbs. 25 ft.lbs. 120 ft.lbs. 37 Front Axle Alignment Specs Caster: Camber: Cross Caster: Toe In: 4.5° ± 1.
SERVICE MANUAL F 38 H H A J J E B B C SHOCK LENGTH @ RIDE HT: FE=17.25±.
Front axle & suspension Torque Requirements description A Front Hanger Pivot B Shackle Bracket Pivot C Upper Shock D Lower Shock E Linkage Rod Assy Locknut F Leveling Valve Lockout G Axle Clamp Group Nuts H Air Spring Mounting Stud Locknuts (All) J Shackle Bracket Locknuts key torque +- 5% 300 ft.lbs. 300 ft.lbs. 125 ft.lbs. 125 ft.lbs. 11 ft.lbs. 8 ft.lbs. 295 ft.lbs. 25 ft.lbs. 120 ft.lbs. 39 Front Axle Alignment Specs Caster: Camber: Cross Caster: Toe In: 4.5° ± 1.
Front Axle & Suspension Interval: Months/Miles • • • • • • • • Torque shock mounting bolts Air Suspension Inspect visually Check axle to suspension fasteners Lubricate steering grease fittings Inspect pin lock bolts Inspect shackle bracket pivot bolt Torque shock mounting bolts Inspect air spring cushions Check air spring fasteners Inspect shocks Check suspension height Check ride height control valve bolts L 12 / 12,000 operation Spring Suspension Inspect visually Check U-bolt torque Lubricate steer
Front axle & suspension SUBJECT: AIRTEK® & SOFTEK Service Instructions for Blue Bird Buses LIT NO: 17730-248 DATE: February January 2008 DATE: 2007 REVISION: REVISION:DC ® 41 h This publication is also available at www.hendrickson-intl.
SERVICE MANUAL 42 L 1 APPENDIX
Front axle & suspension 43 TABLE OF CONTENTS Section 1 Introduction . . . . . . . . . . . . . . . . . . . . . . 2 Section 2 Product Description . . . . . . . . . . . . . . . . 3 Section 3 Important Safety Notice . . . . . . . . . . . . . 6 Section 4 Special Tools . . . . . . . . . . . . . . . . . . . . 11 Section 5 AIRTEK® • SOFTEK® for Blue Bird Buses January 2008 Rev. D Section 9 Parts Lists For Vision Buses AIRTEK – 10K Capacity . . . . . . . . . . . . . . 12 SOFTEK – 8K/10K Capacity . . . .
SERVICE MANUAL AIRTEK®• SOFTEK® for Blue Bird Buses SECTION 1 Introduction This publication is intended to acquaint and assist maintenance personnel in the preventive maintenance, service, repair and rebuild of the following Hendrickson equipment as installed on applicable Blue Bird Buses: 44 NOTE ■ AIRTEK® — An integrated front air suspension with the STEERTEK axle. ■ SOFTEK® — An integrated steel spring mechanical suspension with the STEERTEK axle.
Front axle & suspension AIRTEK®• SOFTEK® for Blue Bird Buses SECTION 2 Product Description BLUE BIRD VISION BUSES FIGURE 2-1 AIRTEK® Air Suspension System Capacity: 10,000 pounds FIGURE 2-2 SOFTEK® Mechanical Suspension System 45 Capacity: 8,000/10,000 pounds BLUE BIRD ALL AMERICAN BUSES FIGURE 2-3 AIRTEK® Air Suspension System Capacity: 14,600 pounds FIGURE 2-4 SOFTEK® Mechanical Suspension System Capacity: 13,200/14,600 pounds RIGHT HAND DRIVE AXLE FIGURE 2-5 17730-248 3 Product Description
SERVICE MANUAL AIRTEK®• SOFTEK® for Blue Bird Buses STEERTEK — The box-shaped design provides a stiffer axle and resists torsional, longitudinal and vertical loads more effectively than traditional axle beams. Together with the front limbs of the leaf springs, the robotically welded axle beam forms a torsion system, enhancing roll stability characteristics and improving handling. 46 Axle clamp group — The patented clamp group provides four-sided clamping pressure.
Front axle & suspension AIRTEK®• SOFTEK® for Blue Bird Buses TECHNICAL NOTES 1. AIRTEK and SOFTEK are approved for 100% on-highway use; other applications must be preapproved by Hendrickson Sales Engineering. System capacity rating for the suspension represents maximum loads on tires at ground level. 2 The STEERTEK axle for the Vision is available with 69" kingpin intersection (KPI). The STEERTEK axle for the All American is available with 71" kingpin intersection (KPI). 3.
SERVICE MANUAL AIRTEK®• SOFTEK® for Blue Bird Buses SECTION 3 Important Safety Notice Proper maintenance, service and repair are important to the reliable operation of the suspension. The procedures recommended by Hendrickson and described in this technical publication are methods of performing such maintenance, service and repair. The warnings and cautions should be read carefully to help prevent personal injury and to assure that proper methods are used.
Front axle & suspension AIRTEK®• SOFTEK® for Blue Bird Buses SAFETY PRECAUTIONS FASTENERS LOOSE OR OVER TORQUED FASTENERS CAN CAUSE COMPONENT DAMAGE, LOSS OF VEHICLE CONTROL, PROPERTY DAMAGE, OR SEVERE PERSONAL INJURY. MAINTAIN CORRECT TORQUE VALUE AT ALL TIMES. CHECK TORQUE VALUES ON A REGULAR BASIS AS SPECIFIED. 49 AIR SPRINGS AIR SPRING ASSEMBLIES MUST BE DEFLATED PRIOR TO LOOSENING ANY CLAMP GROUP HARDWARE. UNRESTRICTED AIR SPRING ASSEMBLIES CAN VIOLENTLY SHIFT.
SERVICE MANUAL AIRTEK®• SOFTEK® for Blue Bird Buses TORCH/WELDING DO NOT USE A CUTTING TORCH TO REMOVE ANY ATTACHING FASTENERS. THE USE OF HEAT ON SUSPENSION COMPONENTS WILL ADVERSELY AFFECT THE STRENGTH OF THESE PARTS. A COMPONENT DAMAGED IN THIS MANNER CAN RESULT IN THE LOSS OF VEHICLE CONTROL AND POSSIBLE PERSONAL INJURY OR PROPERTY DAMAGE. 50 EXERCISE EXTREME CARE WHEN HANDLING OR PERFORMING MAINTENANCE IN THE AREA OF THE SPRING ASSEMBLY AND AXLE.
Front axle & suspension AIRTEK®• SOFTEK® for Blue Bird Buses SUPPORT THE VEHICLE PRIOR TO SERVICING PLACE THE VEHICLE ON A LEVEL FLOOR AND CHOCK THE WHEELS TO HELP PREVENT THE VEHICLE FROM MOVING. NEVER WORK UNDER A RAISED VEHICLE SUPPORTED BY ONLY A FLOOR JACK. ALWAYS SUPPORT A RAISED VEHICLE WITH SAFETY STANDS. BLOCK THE WHEELS AND MAKE SURE THE UNIT WILL NOT ROLL BEFORE RELEASING BRAKES. A JACK CAN SLIP OR FALL OVER. SERIOUS PERSONAL INJURY CAN RESULT. 51 AXLE AXLE CAMBER IS NOT ADJUSTABLE.
SERVICE MANUAL AIRTEK®• SOFTEK® for Blue Bird Buses PARTS CLEANING SOLVENT CLEANERS CAN BE FLAMMABLE, POISONOUS AND CAUSE BURNS. TO HELP AVOID SERIOUS PERSONAL INJURY, CAREFULLY FOLLOW THE MANUFACTURER’S PRODUCT INSTRUCTIONS AND GUIDELINES AND THE FOLLOWING PROCEDURE: 52 1. WEAR PROPER EYE PROTECTION 2. WEAR CLOTHING THAT PROTECTS YOUR SKIN 3. WORK IN A WELL VENTILATED AREA 4. DO NOT USE GASOLINE, OR SOLVENTS THAT CONTAIN GASOLINE. GASOLINE CAN EXPLODE 5.
Front axle & suspension AIRTEK®• SOFTEK® for Blue Bird Buses SECTION 4 Special Tools These shop made tools are designed to install and remove kingpin bushings. Bushing tools are made from cold rolled steel or equivalent. Drawings are for reference only. Hendrickson does not supply these tools.
SERVICE MANUAL SECTION 5 Parts List Blue Bird Vision Buses - 10K Capacity 54 Parts Lists L 1 APPENDIX 12 17730-248
Front axle & suspension AIRTEK® for Blue Bird Vision Buses - 10K Capacity KEY NO. PART NO.
SERVICE MANUAL Blue Bird Vision Buses - 8K/10K Capacity 9 10 11 12 45 11 56 9 49 13a 12 8a 45 10 2 4 11 1 7 11 48 4 49 17 16 4 7 50 17 14 18 4 1 17 13a 16 8a 14 4 4 3 3 5 17 18 14 43 16 17 43 4 17 14 41 6 16 18 17 41 17 5 5 4 6 48 2 5 30 29 25 24 23 26 21 32 31 34 25 30 24 19 29 28 30 26 22 44 20 31 32 34 39 40 26 37 38 42 46 46 47 35 24 44 27 30 47 37 38 39 40 26 24 42 25 46 46 36 47 47 33 25 51 45 For vehicles built prio
Front axle & suspension SOFTEK® for Blue Bird Vision Buses - 8K/10K Capacity KEY NO. PART NO.
SERVICE MANUAL Blue Bird All American Buses 14.
Front axle & suspension AIRTEK® for Blue Bird All American Buses - 14.6K Capacity KEY NO. PART NO.
SERVICE MANUAL Blue Bird All American Buses 13.2K/14.
Front axle & suspension SOFTEK® for Blue Bird All American Buses - 13.2K/14.6K Capacity KEY NO. PART NO.
SERVICE MANUAL Right Hand Drive for Blue Bird All American Buses 13.2K/14.6K Capacity 62 KEY NO. PART NO. 67905-402 67905-404 67905-405 67905-407 1 58900-035 58900-033 58900-031 58900-055 58900-053 58900-051 2 3 4 58900-036 58900-034 58900-032 58900-056 58900-054 58900-052 60904-001 70903-001 60961-040 60961-009 60961-039 5 6 7 59156-000 58937-000 58909-000 60961-043 60961-041 DESCRIPTION NO.REQ. STEERTEK Axle Assembly (Includes Key Nos. 1-25) SOFTEK Standard Drop - 13.2K AIRTEK Deep Drop - 13.
Front axle & suspension AIRTEK®• SOFTEK® for Blue Bird Buses SECTION 6 On Highway and On Roadway Recommended Towing Procedure Hendrickson recommends that a vehicle equipped with a STEERTEK axle be towed by the following methods (listed in order of preference) for ON HIGHWAY or ON ROADWAY applications. 63 1. Wheel lift method, the ideal towing procedure 2. Towing the vehicle from the rear method 3.
SERVICE MANUAL AIRTEK®• SOFTEK® for Blue Bird Buses AXLE FORK LIFT METHOD This is an alternative method for towing the vehicle, but requires standard 5" forks, (see Figures 6-2 and 6-3) and designated lift points inside the axle clamp groups. The following procedure must be used: 64 ■ Place a spacer on the boom, to provide adequate clearance between the oil pan and the boom if necessary. Lift the vehicle in order to place spacer under tires.
Front axle & suspension AIRTEK®• SOFTEK® for Blue Bird Buses OFF ROADWAY TOWING METHOD WHEN A VEHICLE IS DISABLED AND EQUIPPED WITH A STEERTEK AXLE, CARE MUST BE TAKEN TO ENSURE THERE IS NO DAMAGE TO THE SUSPENSION OR AXLE WHEN TOWING THE VEHICLE. THE USE OF A TOW STRAP IS NECESSARY TO TOW A DISABLED VEHICLE INTO A REPAIR FACILITY PARKING LOT INTO THE SHOP BAY. THE TOW STRAPS SHOULD BE CONNECTED TO THE TOW HOOKS PROVIDED BY THE VEHICLE MANUFACTURER AT THE FRONT OF THE BUMPER.
SERVICE MANUAL AIRTEK®• SOFTEK® for Blue Bird Buses SECTION 7 Preventive Maintenance Following appropriate inspection procedure is important to help ensure the proper maintenance and operation of the AIRTEK®/SOFTEK® suspension system and component parts function to their highest efficiency.
Front axle & suspension AIRTEK®• SOFTEK® for Blue Bird Buses LUBRICATION INTERVALS For vehicles equipped with the STEERTEK axle, regular lubrication intervals should be followed to help prevent premature wear to the kingpin bushings and tie rod ends, see lubrication chart below. NOTE The recommended service lubrication interval is a guideline, the vehicle may require increased lubrication interval depending on severity of operation.
SERVICE MANUAL AIRTEK®• SOFTEK® for Blue Bird Buses TIE ROD END LUBRICATION LUBRICATION PROCEDURE 1. Turn the vehicle wheels straight ahead. 2. Wipe the zerk fitting and grease gun tip with clean shop towels. 3. Wipe the seal/boot clean with shop towels. 4. Attach a grease gun to the zerk fitting. Either a hand or pneumatic grease gun is acceptable. If air operated grease gun is used, system air pressure should not exceed 150 psi (1035 kPa).
Front axle & suspension AIRTEK®• SOFTEK® for Blue Bird Buses TIE ROD END INSPECTION INSPECTION PROCEDURE Before beginning this inspection procedure, the entire system must be unloaded (i.e., the front end of the vehicle must be raised and supported with safety stands). DO NOT GREASE THE TIE ROD ASSEMBLY BEFORE PERFORMING THE INSPECTION. DOING SO CAN INHIBIT EFFORTS TO DETERMINE ACTUAL WEAR.
SERVICE MANUAL AIRTEK®• SOFTEK® for Blue Bird Buses 8. By hand or using a pipe wrench, with jaw protectors to avoid gouging the cross tube, rotate the cross tube toward the front of the vehicle and then toward the rear. After rotating, center the cross tube. If the cross tube will not rotate in either direction, replace both tie rod ends, see Figure 7-5. FIGURE 7-5 70 FIGURE 7-6 9. Position yourself directly below the tie rod end.
Front axle & suspension AIRTEK®• SOFTEK® for Blue Bird Buses CLAMP GROUP RE-TORQUE INTERVAL 1. Clamp group locknuts must be torque to specification at preparation for delivery. 2. Clamp group locknuts must be re-torqued at 1,000 miles. 3. Thereafter follow the 6 month/ 25,000 mile inspection and annual re-torque interval. 4. Ensure that the clamp group is properly aligned and the hex bolts/U-bolts are seated in the top pad, and the bottom axle wrap is centered on the top axle wrap, see Figure 7-8.
SERVICE MANUAL AIRTEK®• SOFTEK® for Blue Bird Buses The most common conditions of concern are: 72 ■ Overall Fast Wear (Miles per 32nd) ■ Feather Wear ■ Cupping ■ Diagonal Wear ■ Rapid Shoulder Wear (One Shoulder Only) ■ One-Sided Wear FIGURE 7-10 Overall Fast Wear — Fast wear can be described as exhibiting a good, but accelerated wear pattern.
Front axle & suspension AIRTEK®• SOFTEK® for Blue Bird Buses FIGURE 7-13 Diagonal Wear — Can be described as localized flat spots worn diagonally across the tread at approximately 25-35° angles, often repeating around the tread circumference. For more information, see TMC RP 219A publication, page 20. 73 Diagonal wear is usually caused by bad wheel bearings, toe out, mismounting of tire and wheel assembly to axle, and mismatched duals for size and/or inflation pressures. It may start as brake skid.
SERVICE MANUAL AIRTEK®• SOFTEK® for Blue Bird Buses AXLE WRAP LINER INSPECTION FIGURE 7-16 INSPECTION PROCEDURE ■ Axle wrap liners are installed on the STEERTEK axle to help prevent any type of abrasion on the axle at the clamp group area. Any time an axle wrap is removed it is mandatory that the axle wrap liner be replaced. ■ Liner Crack Criteria: It is possible for the axle wrap liner to crack during service.
Front axle & suspension AIRTEK®• SOFTEK® for Blue Bird Buses VISUAL INSPECTION Look for these potential problems when doing a visual inspection. Inspect the shock absorbers fully extended. Replace as necessary. FIGURE 7-18 75 LEAKING VS. MISTING SHOCK VISUAL INSPECTION The inspection must not be conducted after driving in wet weather or a vehicle wash; shocks need to be free from water. Many shocks are often mis-diagnosed as failures.
SERVICE MANUAL AIRTEK®• SOFTEK® for Blue Bird Buses KINGPIN BUSHING INSPECTION INSPECTION PROCEDURE (STEERING KNUCKLE LATERAL MOVEMENT) 1. Chock the wheels to help prevent the vehicle from moving. Set the parking brake. 2. Use a jack to raise the vehicle until the wheels are off the ground. Support the vehicle with safety stands. 76 FIGURE 7-20 FIGURE 7-21 3. CHECKING THE UPPER KINGPIN BUSHING.
Front axle & suspension AIRTEK®• SOFTEK® for Blue Bird Buses STEERING KNUCKLE INSPECTION CHECKING VERTICAL END PLAY (UP AND DOWN MOVEMENT) The operating spec for vertical clearance on the steering knuckle is 0.008" to 0.030". 1. Chock the rear tires to help prevent the vehicle from moving. 2. Set the parking brakes. 3. Use a jack to raise the vehicle until both tires are 1" off the ground. 77 FIGURE 7-23 4. Place a dial indicator on each side of the axle as follows: a.
SERVICE MANUAL AIRTEK®• SOFTEK® for Blue Bird Buses SHACKLE THRUST WASHER INSPECTION (If Equipped) NOTE SOFTEK Vision 8K capacity vehicles built after 02/2007, and all other vehicles built after 11/2006 are not equipped with shackle thrust washers. In normal use these components will function satisfactorily, even though the components may show some wear. 78 FIGURE 7-24 Shackle Bracket M20 Locknut Tightening Torque 290-310* ft. lbs.
Front axle & suspension AIRTEK®• SOFTEK® for Blue Bird Buses FRONT HANGER/REAR SHACKLE BRACKET SURFACE PAINT WEAR The Hendrickson front suspension systems AIRTEK and SOFTEK equipped on Blue Bird buses, utilize rubber bushings in the leaf springs. These rubber bushings allow the leaf spring to deflect and contact the front hanger and shackle plates when the bus encounters high lateral acceleration (ex. a highway clover leaf).
SERVICE MANUAL AIRTEK®• SOFTEK® for Blue Bird Buses SECTION 8 Alignment & Adjustments 80 ALIGNMENT DEFINITIONS FIGURE 8-1 Ackermann Steering Geometry — The geometry of the four bar linkage ACKERMANN GEOMETRY consisting of the front axle beam pivot points, tie rod arms, and cross tube and attempts to provide free rolling of front tires in a turn. Ackermann geometry is dependent upon the steering axle track-width and wheelbase of the vehicle.
Front axle & suspension AIRTEK®• SOFTEK® for Blue Bird Buses FIGURE 8-4 KINGPIN INCLINATION IN DEGREES Kingpin Inclination (KPI) — The inward tilt of the kingpin from the vertical. This front suspension parameter has a pronounced effect on steering effort and returnability. As the front wheels are turned around an inclined kingpin, the front of the truck is lifted.
SERVICE MANUAL AIRTEK®• SOFTEK® for Blue Bird Buses FIGURE 8-8 Toe-Out on Turns — (See Ackermann Geometry). Excessive turning angles such as those encountered in pickup and delivery operations may contribute to premature tire wear. Be advised that the greater the turning angles, the more that toe and camber change. If you have any doubt regarding the optimum turning angles for your operation, contact the vehicle’s manufacturer, axle OEM, tire OEM and alignment equipment manufacturer for advice.
Front axle & suspension AIRTEK®• SOFTEK® for Blue Bird Buses REAR AXLE AND REAR SUSPENSION Rear axle misalignment can cause front tire wear. If the outer edge of one front tire is worn and the inner edge of the other front tire is worn, check the following: ■ Make sure the rear axle (especially a tandem axle) is correctly aligned. Refer to the procedure from the manufacturer of the vehicle or the suspension.
SERVICE MANUAL AIRTEK®• SOFTEK® for Blue Bird Buses Major wheel alignment is accomplished in the following sequence of operation: 1. Inspect all the systems that influence the wheel alignment. Refer to the “Inspection Prior to Alignment” in this section. 2. Check and adjust the maximum turn angle, (see “Steering Stop Procedure” in this section), see Figures 8-9 and 8-10. 84 3. If the vehicle has power steering, check and adjust, if necessary, the pressure relief in the power steering system.
Front axle & suspension AIRTEK®• SOFTEK® for Blue Bird Buses AIRTEK RIDE HEIGHT ADJUSTMENT 1. Drive the vehicle onto a level surface. 2. Free and center all suspension joints by slowly moving vehicle back and forth several times without using the brakes. It is important when coming to a complete stop to verify that the brakes are released. 3. Chock front wheels.
SERVICE MANUAL AIRTEK®• SOFTEK® for Blue Bird Buses 9. The different referenced ride height measurements are as specified in the following chart. If the reference measurement is not within ± ¼" of the specification, the ride height MUST be adjusted.
Front axle & suspension AIRTEK®• SOFTEK® for Blue Bird Buses AIRTEK HEIGHT CONTROL VALVE TEST The height control valve test can be done with Barksdale Test Kit (Model 55521). KIT CONTENTS QTY. DESCRIPTION QTY. DESCRIPTION QTY. DESCRIPTION 1 1 Gauge (F3) Fitting 1 1 Valve (T1) Tubing ¼" 2 1 Plug Fitting 1 Flush Plug 1 Tool 1 O-Ring 87 HEIGHT CONTROL VALVE TEST INSTRUCTIONS 1. Disconnect linkage from valve handle. 2.
SERVICE MANUAL AIRTEK®• SOFTEK® for Blue Bird Buses STEERING STOP ADJUSTMENT PROCEDURE When the axle or lower steering knuckle is replaced, the steering stop adjustment must be checked. The steering stop adjustment procedure is as follows: 1. Drive truck onto turntables and chock the rear wheels. 2. Measure the wheel cut. The wheel cut is determined by steering the tires.
Front axle & suspension AIRTEK®• SOFTEK® for Blue Bird Buses 8. Install the trammel bar and measure the distance between the scribe marks at the front of the steer axle tires. Record the measurement, see Figure 8-19. NOTE When setting up the trammel bar the pointers should be level with the spindles at the front and rear of the steer axle tires. 9.
SERVICE MANUAL AIRTEK®• SOFTEK® for Blue Bird Buses SPRING EYE RE-TORQUE This procedure to re-torque is necessary when replacing ■ Front Hanger 90 ■ Shackle Assembly ■ Steel Leaf Spring Assembly AIRTEK RE-TORQUE PROCEDURE FIGURE 8-21 1. Chock the rear wheels of the vehicle to prevent movement. 2. Verify ride height. Adjust if necessary, see AIRTEK Ride Height adjustment procedure in this section. 3. Loosen all six (6) front and rear spring eye bolts, see Figure 8-21.
Front axle & suspension AIRTEK®• SOFTEK® for Blue Bird Buses SOFTEK RE-TORQUE PROCEDURE FIGURE 8-23 91 1. Chock the wheels. 2. Loosen all six (6) front and rear spring eye bolts, see Figure 8-23. NOTE Do not remove the spring eye bolts. 3. Let the suspension settle. 4. Tighten the front M20 spring eye bolt locknuts to vehicle manufacturer's specifications. 5. Tighten the rear M20 spring eye bolt and shackle bolt locknuts to vehicle manufacturer's specifications. 6.
SERVICE MANUAL AIRTEK®• SOFTEK® for Blue Bird Buses SECTION 9 Component Replacement FASTENERS 92 Hendrickson recommends that when servicing the vehicle to replace the removed fasteners with new equivalent fasteners. Maintain correct torque values at all times. Check torque values as specified. See Hendrickson’s Torque Specifications in the Appendix of this publication. If non-Hendrickson fasteners are used follow torque specifications listed in the vehicle manufacturer’s service manual.
Front axle & suspension AIRTEK®• SOFTEK® for Blue Bird Buses ASSEMBLY 1. Attach the height control valve on the vehicle frame as shown in Figure 9-1. FIGURE 9-2 10K 2. Attach the ¼" washers and the locknuts. Do not tighten the locknuts to specified torque until after the proper ride height is attained. Mount the height control valve parallel to flange of the frame, see Figure 9-2.
SERVICE MANUAL AIRTEK®• SOFTEK® for Blue Bird Buses FIGURE 9-4 14.6K ¼" Nylon Air Line 4. Remove the air lines from the height control valve, see Figure 9-4. The air lines are push-to-connect. Push in on the air line to release tension, push down on the collar and pull out the air line. 94 5. Remove the two ¼" mounting nuts and washers. 6. Remove the height control valve. Air Spring Bracket Leveling Valve Arm Air Spring ASSEMBLY 1. Re-install the air fittings into the height control valve.
Front axle & suspension AIRTEK®• SOFTEK® for Blue Bird Buses AIRTEK AIR SPRING – 10K DISASSEMBLY 1. Place the vehicle on level floor. 2. Chock the wheels. 3. Raise the frame. 4. Support the vehicle with frame stands. 95 WHEN SERVICING THE VEHICLE OR ATTACHING AN AIR SPRING AND THE VEHICLE IS ON THE GROUND, PRIOR TO AIRING THE SUSPENSION SYSTEM MAKE CERTAIN THE AIR SPRING LOCATOR IS INDEXED INTO THE UPPER AIR SPRING BRACKET PROPERLY, AND THE AIR SPRING IS FULLY SEATED ON THE SPRING TOP PAD.
SERVICE MANUAL AIRTEK®• SOFTEK® for Blue Bird Buses ASSEMBLY 1. Insert the air spring into the top pad. Make sure the lock tabs click in place. 2. Compress the air spring and slide into vertical position. There is a locating nodule on the air spring to index the position in the upper air spring bracket. 3. Pull the air spring up into the upper air spring bracket until the air spring snaps into place in the upper air spring bracket. Verify all four lock-tabs are engaged, see Figure 9-8.
Front axle & suspension AIRTEK®• SOFTEK® for Blue Bird Buses AIRTEK AIR SPRING – 14.6K DISASSEMBLY 1. Place the vehicle on level floor. 2. Chock the wheels. 3. Raise the frame. 4. Support the vehicle with frame stands. 97 WHEN SERVICING THE VEHICLE OR ATTACHING AN AIR SPRING AND THE VEHICLE IS ON THE GROUND, PRIOR TO AIRING THE SUSPENSION SYSTEM MAKE CERTAIN THE AIR SPRING LOCATOR IS INDEXED INTO THE UPPER AIR SPRING BRACKET PROPERLY, AND THE AIR SPRING IS FULLY SEATED ON THE SPRING TOP PAD.
SERVICE MANUAL AIRTEK®• SOFTEK® for Blue Bird Buses 10. Remove the ¾" upper air spring locknut from the air spring bracket. 11. Remove the air spring. ASSEMBLY 1. Compress the air spring and slide into vertical position. 2. There is a locating ½" stud and ¾" threading stud on top of the air spring. 3. There are two studs on the bottom of the air spring. Guide studs through the air spring bracket and properly seat the lower air spring piston into the top axle pad.
Front axle & suspension AIRTEK®• SOFTEK® for Blue Bird Buses AIRTEK FRONT LEAF SPRING FRAME HANGER DISASSEMBLY 1. Place the vehicle on level floor. 2. Chock the wheels. 3. Raise the frame. 4. Support the vehicle with frame stands. 5. Suspend the front axle from the shock absorbers.
SERVICE MANUAL AIRTEK®• SOFTEK® for Blue Bird Buses PRIOR TO AND DURING DEFLATION AND INFLATION OF THE FRONT AIR SUSPENSION SYSTEM, ENSURE THAT ALL PERSONNEL AND EQUIPMENT ARE CLEAR FROM UNDER THE VEHICLE AND AROUND THE SERVICE AREA, FAILURE TO DO SO CAN CAUSE SERIOUS PERSONAL INJURY, DEATH, OR PROPERTY DAMAGE. 100 5. See additional Air Spring Cautions and Warnings in the Important Safety Notice Section of this publication prior to inflating or deflating the suspension system. 6.
Front axle & suspension AIRTEK®• SOFTEK® for Blue Bird Buses 4. Remove the frame stands and lower frame. 5. Tighten M20 shackle locknut to vehicle manufacturer's specifications. 6. Remove the wheel chocks. AIRTEK REAR SHACKLE FRAME BRACKET 101 DISASSEMBLY 1. Place the vehicle on level floor. 2. Chock the wheels. 3. Raise the frame. 4. Support the vehicle with frame stands. 5. Suspend the front axle from the shocks.
SERVICE MANUAL AIRTEK®• SOFTEK® for Blue Bird Buses FIGURE 9-14 102 ASSEMBLY 1. Install the shackle bracket on the frame. 2. Install new frame fasteners. Follow manufacturer's guidelines. 3. Install the thrust washers (if equipped) and shackle plates with the M20 bolts, washers and locknuts. Snug the shackle bolts. DO NOT tighten. 4. Remove the frame stands and lower frame.
Front axle & suspension AIRTEK®• SOFTEK® for Blue Bird Buses 9. Inspect the shackle assembly and both thrust washers (if equipped) for excessive wear or damage. See Thrust Washer Inspection in the Preventive Maintenance Section of this publication. Hendrickson recommends the thrust washers be replaced when this assembly is serviced. 10. If damaged or worn excessively, replace with Genuine Hendrickson Parts as detailed in the Component Replacement Section of this publication.
SERVICE MANUAL AIRTEK®• SOFTEK® for Blue Bird Buses SOFTEK RUBBER AXLE STOP FIGURE 9-17 8K/10K 13.2K/14.6K Rubber Stop REMOVAL 1. Insert a small pry bar Top Pad between the rubber stop and the inside of the top pad. 2. Apply downward force on the pry bar and pull the rubber stop out of the top pad, see Figure 9-17. 3. Inspect the top pad and frame rail flange for any contact damage. 4. Clean any debris from inside the top pad. 104 Rubber Stop Top Pad INSTALLATION 1.
Front axle & suspension AIRTEK®• SOFTEK® for Blue Bird Buses PRIOR TO AND DURING DEFLATION AND INFLATION OF THE FRONT AIR SUSPENSION SYSTEM, ENSURE THAT ALL PERSONNEL AND EQUIPMENT ARE CLEAR FROM UNDER THE VEHICLE AND AROUND THE SERVICE AREA, FAILURE TO DO SO CAN CAUSE SERIOUS PERSONAL INJURY, DEATH, OR PROPERTY DAMAGE. 3. See additional Air Spring Cautions and Warnings in the Important Safety Notice Section of this publication prior to inflating or deflating the suspension system. 105 4.
SERVICE MANUAL AIRTEK®• SOFTEK® for Blue Bird Buses THE PUSH-TO-CONNECT FITTINGS ARE NON-SERVICEABLE. IT IS NECESSARY TO CLEAN THE DIRT AND DEBRIS AWAY FROM THE PUSH-TO-CONNECT FITTINGS AND THE AIR LINES TO HELP PREVENT ANY FOREIGN MATERIAL FROM ENTERING THE AIR SPRING, AIR SYSTEM OR DAMAGING THE PUSH-TO-CONNECT FITTINGS. CLEAN PUSH-TO-CONNECT FITTINGS USING SOAPY WATER AND A SOFT BRISTLED BRUSH AND DRY WITH COMPRESSED AIR. 106 7. Disconnect the air lines at the air springs. 8.
Front axle & suspension AIRTEK®• SOFTEK® for Blue Bird Buses 11. Remove the ¾" clamp group locknuts and discard. DO NOT USE A CUTTING TORCH TO REMOVE CLAMP GROUP BOLTS OR ATTACHING FASTENERS. THE USE OF SUCH HEAT ON SUSPENSION COMPONENTS CAN ADVERSELY AFFECT THE STRENGTH OF THESE PARTS. A COMPONENT DAMAGED IN THIS MANNER CAN RESULT IN THE LOSS OF VEHICLE CONTROL AND POSSIBLE PERSONAL INJURY OR PROPERTY DAMAGE.
SERVICE MANUAL AIRTEK®• SOFTEK® for Blue Bird Buses PRIOR TO AND DURING DEFLATION AND INFLATION OF THE FRONT AIR SUSPENSION SYSTEM, ENSURE THAT ALL PERSONNEL AND EQUIPMENT ARE CLEAR FROM UNDER THE VEHICLE AND AROUND THE SERVICE AREA, FAILURE TO DO SO CAN CAUSE SERIOUS PERSONAL INJURY, DEATH, OR PROPERTY DAMAGE. 108 11. See additional Air Spring Cautions and Warnings in the Important Safety Notice Section of this publication prior to inflating or deflating the suspension system. 12. Install air spring.
Front axle & suspension AIRTEK®• SOFTEK® for Blue Bird Buses FIGURE 9-21 Front Hanger M20 Bolt 109 Rear Hanger Shock Absorber M20 Locknut Tightening Torque *290-310 ft. lbs. ¾" Lower Shock Bolt M20 Bolt M20 Washer Leaf Spring ¾" Lower Shock Locknut Tightening Torque *125-135 ft. lbs. Rear Shackle Plate M20 Locknut Tightening Torque *290-310 ft. lbs. Dowel Pin Axle Spacer Axle & Kingpin Assembly Top Wrap Bottom Axle Wrap Liner Bottom Axle Wrap ¾" Clamp Group Locknut Tightening Torque 285-305 ft.
SERVICE MANUAL AIRTEK®• SOFTEK® for Blue Bird Buses FIGURE 9-23 10. Tighten the clamp group locknuts evenly in 50 foot pounds increments to 285-305 foot pounds torque in the proper pattern to achieve uniform bolt tension, see Figure 9-23. 11. Remove the frame supports and load the front axle with the vehicle weight. 110 12. Tighten the M20 spring eye bolt locknuts to vehicle manufacturer's specifications.
Front axle & suspension AIRTEK®• SOFTEK® for Blue Bird Buses 3. Apply a thin coating of anti-seize compound to the shock absorber lower mounting bolt shank, to the mating face of the axle wrap and spacer, and to the inside bore of the aluminum axle wrap. This is necessary to help prevent seizing of the bolt to the aluminum axle wrap. 4. Install the lower ¾" bolt from the inboard side to the outboard side of the top axle wrap and attach the spacer, washer, and locknut, see Figure 9-24. 111 5.
SERVICE MANUAL AIRTEK®• SOFTEK® for Blue Bird Buses AIRTEK BOTTOM AXLE WRAP DISASSEMBLY 1. Place the vehicle on level floor. 2. Chock the wheels. 3. Raise the frame. 4. Support the vehicle with frame stands. 112 PRIOR TO AND DURING DEFLATION AND INFLATION OF THE FRONT AIR SUSPENSION SYSTEM, ENSURE THAT ALL PERSONNEL AND EQUIPMENT ARE CLEAR FROM UNDER THE VEHICLE AND AROUND THE SERVICE AREA, FAILURE TO DO SO CAN CAUSE SERIOUS PERSONAL INJURY, DEATH, OR PROPERTY DAMAGE. 5.
Front axle & suspension AIRTEK®• SOFTEK® for Blue Bird Buses 3. Install new ¾" clamp group bolts, washers and locknuts. Ensure that the clamp group is properly aligned and the hex bolts are seated in the top pad, and the bottom axle wrap is centered on the top axle wrap, see Figure 9-27. FIGURE 9-28 4. Tighten locknuts evenly to 285-305 foot pounds torque, see Figure 9-28 for proper torque sequence. 113 5. Install Air spring. See Air Spring assembly in this section. 6. Remove the wheel chocks.
SERVICE MANUAL AIRTEK®• SOFTEK® for Blue Bird Buses AIRTEK TOP AXLE WRAP (In Chassis) DISASSEMBLY 1. Place the vehicle on level floor. 2. Chock the wheels. 3. Raise the frame. 4. Support the vehicle with frame stands. 5. Suspend the front axle to remove the load from the spring and wrap leaf assembly.
Front axle & suspension AIRTEK®• SOFTEK® for Blue Bird Buses FIGURE 9-30 115 ASSEMBLY 1. Install the new axle wrap liner on the axle. 2. Spray the axle wrap liner and the axle wrap with a silicon lubricant. 3. Position the axle wrap on the axle, see Figure 9-31. DO NOT STRIKE THE TOP AXLE WRAP WITH A HAMMER. HENDRICKSON RECOMMENDS USING A PLASTIC DEAD BLOW MALLET WITH CARE WHEN INSTALLING THE AXLE WRAP. FIGURE 9-31 4.
SERVICE MANUAL AIRTEK®• SOFTEK® for Blue Bird Buses FIGURE 9-32 116 FIGURE 9-33 16. Tighten the ¾" clamp group locknuts evenly to 285-305 foot pounds torque in the proper sequence, see Figure 9-33. 17. Remove the jack from the axle. 18. Remove the frame stands.
Front axle & suspension AIRTEK®• SOFTEK® for Blue Bird Buses SOFTEK TOP AXLE WRAP (In Chassis) DISASSEMBLY 1. Place the vehicle on level floor. 2. Chock the wheels. 3. Raise the frame. 4. Support the vehicle with frame stands. 5. Suspend the front axle to remove the load from the spring and wrap leaf assembly. 6. Remove the front and rear M20 spring eye bolts, washers and locknuts. Loosen the M20 shackle pivot bolt.
SERVICE MANUAL AIRTEK®• SOFTEK® for Blue Bird Buses FIGURE 9-36 3. Position the axle wrap on the axle, see Figure 9-36. DO NOT STRIKE THE TOP AXLE WRAP WITH A HAMMER. HENDRICKSON RECOMMENDS USING A PLASTIC DEAD BLOW MALLET WITH CARE WHEN INSTALLING THE AXLE WRAP. 118 4. Protect the top surface of the axle wrap with a block of wood, cardboard, or shop towels. 13.2K/14.6K Top Axle Wrap Top Axle Wrap Liner 8K/10K Top Axle Wrap Axle Wrap Guide Pin Axle 5.
Front axle & suspension AIRTEK®• SOFTEK® for Blue Bird Buses AIRTEK FRONT AXLE ASSEMBLY STEERTEK AXLE CLAMP GROUP CONSIST OF THE FOLLOWING COMPONENTS: ■ Top axle wrap ■ Bottom axle wrap ■ Top axle wrap liner ■ Bottom axle wrap liner ■ Top pad ■ ¾" Bolts, washers and nylon locknuts 119 FIGURE 9-39 SHOWN AIRTEK 10K Height Control Valve Linkage Spring Eye Bolt Leaf Spring Air Spring RH Upper Steering Knuckle Top Pad Lower Shock Locknut Rear Shackle Assembly ¾" Bolts LH Upper Steering Knuckle Spacer
SERVICE MANUAL AIRTEK®• SOFTEK® for Blue Bird Buses SOFTEK FRONT AXLE ASSEMBLY STEERTEK AXLE CLAMP GROUP CONSIST OF THE FOLLOWING COMPONENTS: ■ Top axle wrap ■ Bottom axle wrap ■ Top axle wrap liner ■ Bottom axle wrap liner ■ Top pad ■ ¾" Bolts, washers and nylon locknuts 120 FIGURE 9-40 Component Replacement L 1 APPENDIX 78 17730-248
Front axle & suspension AIRTEK®• SOFTEK® for Blue Bird Buses STEERTEK AXLE REMOVAL Refer to Figures 9-39 and 9-40 when replacing the components of the STEERTEK axle. DO NOT USE A TORCH ON CLAMP GROUP BOLTS OR ANY OTHER PART OF THE AIRTEK SUSPENSION. IF THE CLAMP GROUP BOLTS WILL NOT COME LOOSE WITH AN IMPACT WRENCH, USE A CUT OFF WHEEL AND CUT THE SHANK OF THE BOLT.
SERVICE MANUAL AIRTEK®• SOFTEK® for Blue Bird Buses STEERTEK AXLE (Removed from Chassis) AXLE DISASSEMBLY 1. Remove the bottom axle wrap and liner from the axle. 2. Strike the top axle wrap with a dead blow mallet at the front and rear on the underside of the axle wrap to dislodge it from the axle, see Figure 9-41. 122 FIGURE 9-41 3. After removal of the top axle wrap from the axle inspect for cracks or fretting. 4. Remove the tie rod assembly. See Tie Rod disassembly in this section.
Front axle & suspension AIRTEK®• SOFTEK® for Blue Bird Buses AXLE INSTALLATION 1. Place the new axle on the floor jack and position the axle under the vehicle. 2. Install the axle spacer (if equipped) on the top axle wrap prior to raising the axle into position. 3. Raise the axle into position, see Figures 9-43 and 9-44. Care must be taken at this point to ensure that the front leaf spring assemblies' center bolt is aligned correctly in the top axle wrap. FIGURE 9-43 AIRTEK 10K 123 AIRTEK 14.
SERVICE MANUAL AIRTEK®• SOFTEK® for Blue Bird Buses FIGURE 9-45 124 8. Install the new ¾" clamp group bolts, washers and locknuts. Snug the bolts , DO NOT tighten to the specified torque at this time. FIGURE 9-46 9. Ensure that the clamp groups are properly aligned and the bolts are seated in the top pad, and the bottom axle wraps are centered on the top axle wraps, see Figure 9-46. 10. SOFTEK equipped vehicles — proceed to step 13.
Front axle & suspension AIRTEK®• SOFTEK® for Blue Bird Buses 17. Install the tie rod end cotter pins. 18. Connect the drag link. Install the castle nut. Tighten the castle nut to 185 foot pounds, then rotate until the first castle slot lines up with the cotter pin bore in the drag link. Do not back off the nut for cotter pin installation. 19. Install the drag link cotter pin. 125 20. Install the brake backing plate assemblies. 21. Install the brakes, hubs, and wheels as per manufacturer’s guidelines. 22.
SERVICE MANUAL AIRTEK®• SOFTEK® for Blue Bird Buses REMOVAL OF THE CAP SCREWS WILL ALLOW THE STEERING KNUCKLE TO SEPARATE FROM THE AXLE. THE STEERING KNUCKLE MUST BE SUPPORTED BEFORE REMOVAL OF THESE TWO (2) CAP SCREWS. FAILURE TO DO SO CAN CAUSE COMPONENT DAMAGE OR PERSONAL INJURY. FIGURE 9-49 126 9. Remove the 2 socket head cap screws that connect upper kingpin connection to the steering knuckle, see Figure 9-49. 10. Remove the lower steering knuckle from the kingpin by sliding it down the kingpin. 11.
Front axle & suspension AIRTEK®• SOFTEK® for Blue Bird Buses DO NOT USE HOT SOLUTION TANKS OR WATER AND ALKALINE SOLUTIONS TO CLEAN GROUND OR POLISHED PARTS. DAMAGE TO THE PARTS WILL RESULT. THE STEERTEK HAS A UNIQUE AXLE. THE KINGPIN IS CRYOGENICALLY INSTALLED IN THE AXLE. THE KINGPIN IS A NON-REPLACEABLE COMPONENT OF THE AXLE ASSEMBLY. DO NOT TRY TO REMOVE THE KINGPIN. DOING SO WILL DAMAGE THE AXLE AND MAY CAUSE LOSS OF VEHICLE CONTROL, PERSONAL INJURY OR PROPERTY DAMAGE.
SERVICE MANUAL AIRTEK®• SOFTEK® for Blue Bird Buses FIGURE 9-56 FIGURE 9-57 128 KINGPIN BUSHING REMOVAL 1. Remove the retaining ring for the grease cap. 2. A hydraulic shop press with a minimum forcing capacity of 2.5 tons (or use an arbor press) will be required. BEFORE APPLYING HYDRAULIC PRESSURE TO ANY TOOLING SET-UP, ALWAYS CHECK TO BE SURE THE PRESS PLATE, ADAPTERS, AND COMPONENTS BEING WORKED ON ARE POSITIONED PROPERLY, I.E. “IN LINE” WITH THE RAM.
Front axle & suspension AIRTEK®• SOFTEK® for Blue Bird Buses FIGURE 9-60 FIGURE 9-61 129 STEERING KNUCKLE BORE MEASUREMENT Complete the following steering knuckle bore inspection and the measurement instructions prior to installing the kingpin bushing. 1. Measure the upper knuckle bore inside diameter at two locations. Always use an inside micrometer or a telescoping gauge when taking a knuckle bore measurement. Some out-of-roundness at the top and bottom of the bore edges is acceptable.
SERVICE MANUAL AIRTEK®• SOFTEK® for Blue Bird Buses FIGURE 9-65 FIGURE 9-66 FIGURE 9-67 130 KINGPIN BUSHING REAMING REAM THE KINGPIN BUSHINGS WITH AN ADJUSTABLE STRAIGHT FLUTE REAMER. (SEE SPECIAL TOOLS SECTION OF THIS PUBLICATION) DO NOT HONE OR BURNISH THE KINGPIN BUSHINGS. HONING OR BURNISHING WILL DAMAGE THE BUSHINGS AND VOID WARRANTY. WHEN INSTALLING STEERING KNUCKLE COMPONENTS IN A VISE IT IS NECESSARY TO PROTECT THE MACHINED SURFACES FROM GOUGES OR MARRING BY USING BRASS JAWS.
Front axle & suspension AIRTEK®• SOFTEK® for Blue Bird Buses 4. Slide the reamer out of the bottom of the steering knuckle assembly. If it is necessary to remove the reamer from the top, rotate the reamer opposite of cutting rotation. 5. Clean and remove all kingpin bushing material from the steering knuckle assembly. Take special attention to remove material from the grease channels and dimples. 6.
SERVICE MANUAL AIRTEK®• SOFTEK® for Blue Bird Buses FIGURES 9-72 AND 9-73 132 STEERING KNUCKLE ASSEMBLY ASSEMBLY After replacement of the kingpin bushings it is necessary to re-assemble the steering knuckle assemblies. The STEERTEK axle is equipped with two different thrust bearings installed. The composite thrust bearing is installed on the left side of the axle.
Front axle & suspension AIRTEK®• SOFTEK® for Blue Bird Buses SERVICE HINT The easiest way to achieve this is with the grease caps not installed in the knuckle assemblies. This eliminates back pressure. The assembly can then freely slide up and down on the kingpin. If the grease caps are still installed, remove the grease zerks to avoid creating back pressure. Grease zerks will be re-installed at the end of the procedure. 6.
SERVICE MANUAL AIRTEK®• SOFTEK® for Blue Bird Buses 20. Apply loctite to the three brake spider bolts prior to installation into the brake spider. Tighten bolts to 175-200 foot pounds torque. DO NOT GREASE KNUCKLES WITHOUT THE BRAKE SPIDER INSTALLED AND TIGHTENED TO PROPER TORQUE. FAILURE TO DO SO CAN CAUSE COMPONENT DAMAGE RESULTING IN FAILURE AND LOSS OF VEHICLE CONTROL, POSSIBLY CAUSING PERSONAL INJURY OR PROPERTY DAMAGE. 134 21. Install the tie rod end into the lower steering knuckle arm. 22.
Front axle & suspension AIRTEK®• SOFTEK® for Blue Bird Buses 12. Inspect the cross tube for dents, cracks, or thread damage. Replace the cross tube if needed. ASSEMBLY 1. Lubricate the new tie rod end threads with Anti-Seize. NOTE When installing the cross tube the thread direction of the tie rod ends are as follows: ■ A right hand threaded tie rod end will be installed into the right side Ackermann arm. ■ A left hand threaded tie rod end will be installed into the left side Ackermann arm. 135 2.
SERVICE MANUAL AIRTEK®• SOFTEK® for Blue Bird Buses SECTION 10 Plumbing Diagrams AIRTEK SINGLE HEIGHT CONTROL VALVE – 10K 136 When replacing or installing nylon air line tubing into quick-connect fittings it is critical that the end of the air line is cut square. Improper cut of the end of the air line tubing can cause the air line to seat improperly in the quick connect fitting causing air leakage.
Front axle & suspension AIRTEK®• SOFTEK® for Blue Bird Buses AIRTEK DUAL HEIGHT CONTROL VALVES – 14.6K When replacing or installing nylon air line tubing into quick-connect fittings it is critical that the end of the air line is cut square. Improper cut of the end of the air line tubing can cause the air line to seat improperly in the quick connect fitting causing air leakage. 137 ¼" Nylon Air Line S.A.E., D.O.T.
SERVICE MANUAL AIRTEK®• SOFTEK® for Blue Bird Buses 138 96 L 1 APPENDIX 17730-248
Front axle & suspension Appendix Reference Material This technical publication covers Hendrickson Truck Suspension’s recommended procedures for our parts/products. Other components play a major role in overall performance and Hendrickson recommends you follow the specific vehicle manufacturer’s recommendation for care and maintenance. Some recommended procedures have been developed by The Technology & Maintenance Council (TMC) and Hendrickson supports these recommendations.
SERVICE MANUAL Appendix AIRTEK/SOFTEK TROUBLESHOOTING GUIDE CONDITION 140 Worn or damaged kingpins and kingpin bushings Vibration or shimmy of front axle during operation POSSIBLE CAUSE CORRECTION Dirt in system– contaminated lubricant Polish and inspect kingpin, replace bushing and seals, then follow specified lubrication procedures Incorrect lubricant Lubricate axle with specified lubricant Axle not lubricated at scheduled frequency Lubricant axle at scheduled frequency Incorrect lubrication
Appendix Front axle & suspension AIRTEK/SOFTEK TROUBLESHOOTING GUIDE (CONTINUED) POSSIBLE CAUSE CORRECTION Tie rod ends need lubrication Lubricate tie rod end. Make sure lubrication schedule is followed.
SERVICE MANUAL Appendix AIRTEK for Blue Bird Vision Buses - 10K Capacity Hendrickson Recommended Torque Values Provided in Foot Pounds 142 17730–248 A-100 L 1 APPENDIX
Front axle & suspension Appendix AIRTEK for Blue Bird Vision Buses – 10K HENDRICKSON RECOMMENDED TORQUE SPECIFICATIONS NO. COMPONENT QTY.
SERVICE MANUAL Appendix SOFTEK for Blue Bird Vision Buses - 8K/10K Capacity Hendrickson Recommended Torque Values Provided in Foot Pounds 1. *290-310 144 1. *290-310 12. Press Fit 12. Press Fit 11. *125-135 11. *125-135 11. *125-135 2. *290-310 2. & 3. *290-310 3. *290-310 5. Snap Fit 5. Snap Fit 11. *125-135 7. 175-200 8. 40-60 10. **185 5. Snap Fit 7. 175-200 10. **185 8. 40-60 6. 285-305 6. 285-305 9. 60-75 9.
Front axle & suspension Appendix SOFTEK for Blue Bird Vision Buses – 8K/10K HENDRICKSON RECOMMENDED TORQUE SPECIFICATIONS NO. COMPONENT QTY.
SERVICE MANUAL Appendix AIRTEK for Blue Bird All American Buses - 14.
Front axle & suspension Appendix AIRTEK for Blue Bird All American Buses – 14.6K HENDRICKSON RECOMMENDED TORQUE SPECIFICATIONS NO. COMPONENT QTY.
SERVICE MANUAL Appendix SOFTEK for Blue Bird All American Buses - 13.2K/14.
Front axle & suspension Appendix SOFTEK for Blue Bird All American Buses – 13.2K/14.6K HENDRICKSON RECOMMENDED TORQUE SPECIFICATIONS NO. COMPONENT QTY.
SERVICE MANUAL Appendix AIRTEK for Blue Bird Buses FRONT AIR MODULE SUSPENSION ALIGNMENT SPECIFICATION CAMBER1 150 RANGE DESIGN SPECIFICATION MINIMUM MAXIMUM 0.00º ± 1.0º -1.0º +1.0º RIGHT - 0.25º ± 1.0º -1.25º +0.75º CROSS Max 2.0º — — LEFT CAMBER NOTES: 1 The camber angle is not adjustable. Do not bend axle or otherwise try to adjust camber. If found out of specification, notify Hendrickson Tech Services for further information.
Front axle & suspension Appendix SOFTEK for Blue Bird Buses FRONT AIR MODULE SUSPENSION ALIGNMENT SPECIFICATION CAMBER1 RANGE DESIGN SPECIFICATION 0.00º ± 1.0º MINIMUM -1.0º MAXIMUM +1.0º RIGHT - 0.25º ± 1.0º -1.25º +0.75º CROSS Max 2.0º — — LEFT 151 CAMBER NOTES: 1 The camber angle is not adjustable. Do not bend axle or otherwise try to adjust camber. If found out of specification, notify Hendrickson Tech Services for further information.
SERVICE MANUAL Technical Procedure Quiz Technical Procedure Publication Quiz 1) What three items have the greatest influence on tire wear? a) Toe b) Air Pressure 152 c) Camber d) Thrust Angle 2) Caster may be increased or decreased using shims or wedges. True or False 3) Cross caster may be changed using shims or wedges. True or False 4) You may bend a STEERTEK axle to correct for improper camber settings.
Front axle & suspension Technical Procedure Quiz 13) To remove the STEERTEK knuckle you must. a) Drive the kingpin out of the axle bore b) Remove the locking pins before driving the kingpin out c) Remove the two 5/8" socket head cap screws and separate the knuckle assembly d) None of the above 14) What is the maximum allowable specification for lateral movement of the steering knuckle? 153 a) 0.001" b) 0.075" c) 0.030" d) 0.
SERVICE MANUAL Technical Procedure Quiz 25) Prior to performing a total vehicle alignment the following components must be inspected. a) Front and rear spring mounts b) Steer axle tires c) Ride height d) All of the above 26) When the clamp group is disassembled the use of a cutting torch is acceptable to help remove seized bolts and nuts. 154 True or False 27) Prior to steering knuckle re-assembly it is critical that residual Loctite be removed and reapplied from the upper kingpin connection.
