TRW STEERING COLUMN MODELS CA (TILT/TELESCOPIC) AND CT (TILT ONLY) CAM REPLACEMENT KIT

Transcription

1 SERVICE BULLETIN (Not applicable to Mack Trucks Australia) NUMBER: SB DATE: 6/28/02 MODEL: CX, CV, CH, CL TRW STEERING COLUMN MODELS CA (TILT/TELESCOPIC) AND CT (TILT ONLY) CAM REPLACEMENT KIT On steering columns (both tilt/telescopic and tilt only) used in CX, CV, CH and CL model chassis, the actuating cam may break and result in the inability to adjust steering wheel position. Should this condition be experienced, a cam replacement kit (part No X1) is available through the MACK Parts System. This kit covers both the TRW tilt/ telescopic model CA and tilt only model CT steering columns. Cam replacement procedures are as follows: The cam replacement kit is only to be used for steering column repairs that are out of warranty. For warrantable repairs, the steering column assembly must be replaced. Steering Column Removal 1. Drive the vehicle into the service bay and keep the front wheels pointing straight ahead. 2. Shut the engine off and apply the parking brakes. 3. Disconnect the batteries by disconnecting the negative cable first, and then the positive cable. 4. Using a small, flat-bladed screwdriver, pry the horn button from the center of the steering wheel. 5. Disconnect the wire from the spade terminal on the back of the horn button. 6. Remove the nut from the center of the steering wheel, and then use a suitable wheel puller to remove the steering wheel. 7. Remove the cover from the steering column actuator lever. 8. Remove the three Torx fasteners (two on the right-hand side and one on the left-hand side) to remove the plastic lower cover from the steering column. SB Page 1 of 8 SERVICE PUBLICATIONS, ALLENTOWN, PA MACK TRUCKS, INC. 2002

2 9. Separate the plastic trim panel from the lower steering column cover by removing the two button-head fasteners located on each side of the cover. 1 Figure 1 Removing Lever Boot, Button-Head Fasteners and Torx Fasteners 1. Button-head fasteners 2. Torx fasteners 3. Actuator handle cover 10. Trace the turn signal, ignition switch and horn wire harnesses to locate the connectors underneath the dashboard, then disconnect the connectors from the main cab harness. Cut any tie wraps and remove any clamps that secure the harnesses to the cab. 11. Remove the pinch-bolt from the steering shaft U-joint. 12. Remove the six bolts (two at the front of the column and two on each side of the column) that secure the column to the mounting brackets. SB Page 2 of 8

3 2 Figure 2 Removing Steering Column Mounting Bolts 13. Rotate the bottom of the column rearward and disconnect the steering shaft U-joint from the splined steering column shaft. 14. Remove the steering column from the cab. 15. Remove the four screws from the top plate cover, and then separate the top plate cover from the upper cover. After the top plate cover has been removed, remove the lower cover. 3 Figure 3 Separating Top Plate Cover from Upper Cover 1. Upper cover 2. Top plate cover 3. Screws SB Page 3 of 8

4 Cam Replacement 4 Figure 4 Steering Column Model CT (Tilt Only) 1. Top cover mounting screws 2. Top cover 3. Column mounting bracket 4. Lower cover 5. Lower cover screws 6. Capscrew 7. Washer 8. Actuator handle cover 9. Actuator handle 10. Retaining ring 11. Cam 12. Actuator pivot pin NOTE: Above illustration used by permission of TRW Commercial Steering Systems. SB Page 4 of 8

5 5 Figure 5 Steering Column Model CA (Tilt/Telescopic) 1. Top cover mounting screws 2. Top cover 3. Column mounting bracket 4. Wireform 5. Lower cover 6. Lower cover screws 7. Capscrew 8. Washer 9. Actuator handle 10. Actuator handle cover 11. Retaining ring 12. Cam 13. Torsion spring 14. Actuator pivot pin NOTE: Above illustration used by permission of TRW Commercial Steering Systems. 1. Place the steering column in a vise, clamping on the mounting bracket flange. 2. With the column securely clamped in the vise, tilt the column toward the mounting bracket. On tilt/telescopic columns, also telescope the column fully up. 3. Remove the capscrew, washer and actuator handle. The capscrew has a nylon patch lock. To remove, use a 5/32 Allen wrench socket, keeping pressure on the screw to avoid rounding the hex. SB Page 5 of 8

6 4. On tilt/telescopic columns only, useavisegriptoreleasethelowerendofthetorsion spring from its position over the wireform. Guide the spring end until the spring rests in a non-tension position. After relieving the tension, remove the torsion spring. Wear eye protection. The torsion spring in the tilt/telescopic steering column may be under tension, and could snap or fly off when removed. 5. Remove the retaining ring. 6. Remove the actuator cam. 7. On tilt/telescopic columns only, remove all grease from the bracket around the actuator pivot pin, then apply clean grease to the area, and also on the back of the new actuator cam. 8. Place the new actuator cam on the actuator pivot pin with the tail of the cam behind the bracket. 9. Place the new retaining ring into the groove on the actuator pivot pin. Make sure that the retaining ring is seated properly in the groove. 10. On tilt/telescopic columns only, hook the top end of the new torsion spring included with the kit in the same location from which the original spring was removed. Use a vise grip to pull the lower end of the spring into place over the wireform. Wear eye protection when installing the torsion spring. The spring may be under tension, and could snap or fly off during installation. 11. Place the actuator handle onto the actuator pivot pin. 12. Install the new washer and capscrew. Tighten the capscrew to lb-in (8 10 N m). 13. Install the upper cover and the top plate cover. Tighten the four screws to lb-in ( N m). 14. Remove the steering column from the vise. SB Page 6 of 8

7 Steering Column Installation 1. Install the steering column into the cab by inserting the column pivot into the slots located in the steering column mounting bracket. 6 Figure 6 Installing Steering Column 1. Steering column pivot 2. Mounting bracket pivot slots 2. Rotate the steering column forward, toward the front of the vehicle while installing the steering shaft U-joint onto the splined shaft. 3. Once the steering shaft U-joint is installed, align the mounting bolt holes in the sides of the steering column with the holes in the mounting bracket. Once aligned, install the mounting bolts (two in each side of the steering column). Hand-tighten the bolts at this time. 4. Install the remaining two mounting bolts in the front of the steering column. 7 Figure 7 Installing Steering Column Mounting Bolts SB Page 7 of 8

8 5. Install a NEW PINCH BOLT (part No. 3AX1876) and nut (part No. 21AX789) in the steering shaft U-joint. Tighten the pinch bolt to lb-ft ( N m). 6. Tighten the steering column mounting bolts to lb-ft (24 29 N m). 7. Reconnect the turn signal switch, ignition switch and horn wire harness connectors to the main cab wire harness connectors. Use tie wraps and harness clamps to secure the harnesses as they had been originally. Ensure that the horn button is positioned in the top plate cover. 8. Install the steering column lower plastic trim cover and tighten the Torx fasteners to lb-in ( N m). 9. Install the top plastic trim panel and secure to the lower cover using two button-head fasteners. 8 Figure 8 Installing Plastic Trim Covers 1. Button-head fasteners 2. Torx fasteners 3. Actuator handle cover 10. Reinstall the cover onto the steering column actuator lever. 11. Reinstall the steering wheel, making sure that the wheel is properly centered (steering wheel spokes should be parallel with the dashboard). 12. Install the steering wheel nut and tighten to lb-ft (46 55 N m). 13. Connect the horn button wire to the spade terminal located on the back of the horn button, then press the horn button into place in the center of the steering wheel. 14. Reconnect the batteries by connecting the positive cable first, and then the negative cable. SB Page 8 of 8