03-13-2022, 07:44 AM
I’ve collected the following information using the ZF Data Plates on our 2005. The coach was built in 2004 as unit #744. I have no idea how long Newell used the ZF RL-85 suspension and drive train. The Drive Axle has a different designation (A-132/S-91/PP 476774).
Steer Axle Data Plates were located on the left and right steering hubs.
Steer Tag Axle Data Plate was located on the aft side of the horizontal beam, left of centerline.
Drive Axle Data Plate was located on the left driveshaft tube facing aft. The differential has its own data plate mounted on the housing.
Data plates may be difficult to see due road grime, they may have been covered by tape when the undercarriage was painted black. I used simple green HD to clean off the areas where the data plates are mounted. Note: Simple Green HD should not corroded metal parts.
I worked with ZF technical customer service to identify the part numbers listed below. They provided me with diagrams and parts list which I’m also posting. ZF is a enormous German company that manufactures and supplies several lines of motor vehicle equipment. Maneuvering within their system is at first overwhelming and frustrating. I have requested from ZF availability and prices for the parts listed below. I will update information as it becomes available.
Steer RL-85/E
Drive Axle A-132/S-91/PP
Steer Tag Axle RL-85/A
Steer Tag Axle Function, Maintenance, Inspection, Troubleshooting
Steering Gearbox 8098
The following document covers several different types of ZF Servocom systems including the RAS, REAR AXLE STEERING. I urge every ZF owner to study the system so you have a solid understanding how your Active Steerable Tag system functions. It requires ANNUAL inspections and maintenance. There is a pressure accumulator that should be served annually and replaced after 10 years of service.
Pressure accumulators in the ZF RAS look like a small metal soccer ball mounted in the frame between the drive and tag axle. The accumulator is pressurized with nitrogen and works in conjunction with the RAS closed loop hydraulic system pressurized to 250 psi.
The nitrogen side of the accumulator can experience micro leaking of the valves used for testing and servicing. If the pressure in your tag system is not correct you may experience anomalies during operation. There is a pressure sensor installed in the system that is activated at or below 230 psi and turns a light on at the drivers position warning of low pressure situation.
Low pressure in a tag system will manifest while backing up and the tag tires my not move in the correct direction. If the tag pressure is low enough the tires will turn in the wrong direction and backing up is impossible. Don’t force it!
Steering Systems and Accessories for Commercial Vehicles
These are life limited parts steer axle and tag axle steer system. There may be additional parts such as steer axle hub bearings for the control arms.
Steering Axle Tie rod Part # 0501.007.768 (one required)
Steering Axle Tie rod Part # 0501.007.769 (one required)
Steering Axle Tie rod Part # 0501.007.611 (sway bar link-two required)
Control arm bushing Part # 0501.314.963 (eight require)
Sway Bar Link Assembly - LEMFÖRDER 3079901
Steering Tag Axle Tie rod Part # 0501.005.797 (one required)
I have not identified tie rod ends for the steer gearbox hydraulic assist system.
I have not identified tie rod ends for the steer tag axle hydraulic actuator.
These documents provide a wealth of information about the ZF suspension.
Lubrication and Maintenance
Operating Manual
Repair Manual
Time in service is a limiting factor in these steering parts. Keep in mind the coach may have low mileage but time is an enemy to any of these parts. They live in a hostile environment far below the driver’s seat. The tie rod ends have rubber boots designed to protect the inner workings of these parts. If the boot is damaged in any way, the world of road grime and nature’s elements have an open door to enter and degrade the performance of these critical steering parts.
Steer Axle Data Plates were located on the left and right steering hubs.
Steer Tag Axle Data Plate was located on the aft side of the horizontal beam, left of centerline.
Drive Axle Data Plate was located on the left driveshaft tube facing aft. The differential has its own data plate mounted on the housing.
Data plates may be difficult to see due road grime, they may have been covered by tape when the undercarriage was painted black. I used simple green HD to clean off the areas where the data plates are mounted. Note: Simple Green HD should not corroded metal parts.
I worked with ZF technical customer service to identify the part numbers listed below. They provided me with diagrams and parts list which I’m also posting. ZF is a enormous German company that manufactures and supplies several lines of motor vehicle equipment. Maneuvering within their system is at first overwhelming and frustrating. I have requested from ZF availability and prices for the parts listed below. I will update information as it becomes available.
Steer RL-85/E
Drive Axle A-132/S-91/PP
Steer Tag Axle RL-85/A
Steer Tag Axle Function, Maintenance, Inspection, Troubleshooting
Steering Gearbox 8098
The following document covers several different types of ZF Servocom systems including the RAS, REAR AXLE STEERING. I urge every ZF owner to study the system so you have a solid understanding how your Active Steerable Tag system functions. It requires ANNUAL inspections and maintenance. There is a pressure accumulator that should be served annually and replaced after 10 years of service.
Pressure accumulators in the ZF RAS look like a small metal soccer ball mounted in the frame between the drive and tag axle. The accumulator is pressurized with nitrogen and works in conjunction with the RAS closed loop hydraulic system pressurized to 250 psi.
The nitrogen side of the accumulator can experience micro leaking of the valves used for testing and servicing. If the pressure in your tag system is not correct you may experience anomalies during operation. There is a pressure sensor installed in the system that is activated at or below 230 psi and turns a light on at the drivers position warning of low pressure situation.
Low pressure in a tag system will manifest while backing up and the tag tires my not move in the correct direction. If the tag pressure is low enough the tires will turn in the wrong direction and backing up is impossible. Don’t force it!
Steering Systems and Accessories for Commercial Vehicles
These are life limited parts steer axle and tag axle steer system. There may be additional parts such as steer axle hub bearings for the control arms.
Steering Axle Tie rod Part # 0501.007.768 (one required)
Steering Axle Tie rod Part # 0501.007.769 (one required)
Steering Axle Tie rod Part # 0501.007.611 (sway bar link-two required)
Control arm bushing Part # 0501.314.963 (eight require)
Sway Bar Link Assembly - LEMFÖRDER 3079901
Steering Tag Axle Tie rod Part # 0501.005.797 (one required)
I have not identified tie rod ends for the steer gearbox hydraulic assist system.
I have not identified tie rod ends for the steer tag axle hydraulic actuator.
These documents provide a wealth of information about the ZF suspension.
Lubrication and Maintenance
Operating Manual
Repair Manual
Time in service is a limiting factor in these steering parts. Keep in mind the coach may have low mileage but time is an enemy to any of these parts. They live in a hostile environment far below the driver’s seat. The tie rod ends have rubber boots designed to protect the inner workings of these parts. If the boot is damaged in any way, the world of road grime and nature’s elements have an open door to enter and degrade the performance of these critical steering parts.
Kristi & Jeff King
Bentonville, Arkansas
#744 2005 45’ Newell Coach
ZF Suspension/Active Steering Tag Axle
CAT-13 ACERT KCB Engine 525HP 1642 ftlbs Torque Cat Compound Turbocharger 43.5 psi
Allison HD4000MH Transmission with PTO drive.