e r v i c e Maintenance Troubleshooting Oil Change Filter Change Disassembly Assembly ZF Rack and Pinion Power teering Gears ZF Recirculating Ball Power teering Gears (Passenger Cars) 7830/8051 W 07/01 e ZF Lenksysteme GmbH D-73522 chwäbisch Gmünd Telephone (07171) 31-0 Telefax (07171) 31-4396
Important general information This Manual is intended to assist the user in the proper execution the necessary maintenance and repair work on the ZFL product. Read the Manual before starting any inspection or repair work. On completion of the maintenance and repair work, the specialist personnel are responsible for making certain that the product is operating properly before returning it to operation. Please note that the ZFL product must be repaired only in workshops that. employ personnel trained by ZFL. have the prescribed equipment, including a test rig, crack detector and special tools. use ZFL approved spare parts. This Manual is only for technicians who have undergone practical and theoretical training in our Customer ervice chool. Together with service information bulletins, it is intended to supplement their knowledge. As a matter of principle, only the procedures described in the Manual must be carried out. Any additional modification or other work (as, for example, welding etc.) is not allowed and may cause a safety-relevant failure. If, as an exception, a different procedure is required, we will communicate a separate information, valid only for the specific application (e.g. ervice Information). All work carried out on ZFL products must be executed with extreme care and diligence. This applies in particular to products and transmission components from vehicles damaged in accidents. Before dismantling the ZFL-unit, the operating liquid contained in it (e.g. lubricant) must be drained without leaving any residue, if possible, and must be disposed within the internal disposing system of your company and in accordance with applicable regulations. All metals that cannot be reused must be recycled according to the individual materials. All other parts (e.g. sealing parts) must be disposed properly on the basis of the applicable regulations. ZFL does not, of course, accept any liability for damage and its consequences arising from incor rectly or inexpertly executed repairs. This Manual draws attention to notes on safety as follows: Note: Where incorrect and careless work can cause damage to the product. Attention: Where incorrect and careless work can lead to personal injury or endanger life. This Manual is not part of the updating service. The contents of the additional service information bulletins must also be observed. Copyright: The copying, distribution and utilization of this document as well as the communication of its contents to others without expressed authorization is prohibited. Offenders will be held liable for the payment of damages. All rights reserved in the event of the grant of a patent or utility model registration.
Table of Contents Page I. Maintenance... 2 1 Maintenance Intervals... 2 2 Maintenance Work... 2 3 Checking for External Leakproofness... 4 4 Visual Inspection... 4 II. Troubleshooting... 5 1 Fitting the ZF ervotest Tester... 5 2 Checking the Oil Level... 5 3 Bleeding the teering ystem... 6 4 Checking the Hydraulic Functioning of the teering ystem... 8 III. Oil Change... 10 1 Draining the Oil... 10 2 Oil Fill... 10 IV. Filter Change... 10 V. Disassembly of the teering Box... 11 VI. Assembly of the teering Box... 12 1 Assembly... 12 2 Filling the teering ystem with Oil and Bleeding... 13 3 Checking the Front Axle Geometry... 13 VII. pecial Tools... 14 VIII. Inspection Report... 15 Attention: The descriptions below are generally binding and apply to work to be carried out on ZF units. In addition, the vehicle manufacturers instructions must be complied with. Maintenance, Troubleshooting, Oil-/Filter Change, Disassembly, Assembly 1
Maintenance I. Maintenance 1 Maintenance Intervals To increase road safety, we recommend to proceed to a maintenance of the steering system every 50,000 kms. 2 Maintenance Work 2.1 Checking the Fit of the Mounting Bolts Check whether the bolts on the steering gear (steering box, transmission parts, steering column) are fitting closely. If required retighten the bolts in accordance with the vehicle manufacturer s instructions. 2.2 Checking the traight Ahead Position of the teering Gear and the Vehicle Place the front wheels on swivel plates. Determine the total number of steering wheel turns. From the lock stop, rotate the steering gear back by half the number of total steering wheel turns. Then continue to rotate until the marks on the steering input shaft/protecting cap coincide with the marks on the valve housing. Check whether the steered wheels are in the straight ahead driving position. A correction can be made by turning the ball joint at the tie rod further in or out. Attention: If a correction of the setting turns out to be necessary, it may well be that this necessity originates in a preceding accident-like event. Therefore: check whether the steering gear is installed in a twisted position check all further transmission parts for bending, cracks or torsion. Deformed parts may not be re-bent but must be replaced. 2 Maintenance, Troubleshooting, Oil-/Filter Change, Disassembly, Assembly
Maintenance 2.3 Checking the Play of the teering Column By moving (shaking) the steering wheel sideward to and fro, check whether there is any play. If so, check the steering column bearing arrangement or replace the bearing. 2.4 Checking the Universal Joint and the Universal Joint Disc between Upper teering Input haft and teering Box for Angular Play and tiff Operation If play or stiff operation are found, repair or replace the defective component. 2.5 Checking the High pot Adjustment (Increase in Frictional Torque) (Can be done for ZF Recirculating Ball Power teering Gears only) Rotate the steering gear to straight ahead. To be able to do so, determine the total number of steering wheel turns. From the lock stop, rotate the steering gear back by half the total number of steering wheel turns. Check whether the straight ahead driving marks coincide. Remove the drag link/tie rod from the drop arm. Fit the torque meter to the steering wheel - cf. Chapter VII.. Rotate the steering gear to one end position and, while doing so, measure the frictional torque required to rotate the steering gear outside the straight ahead driving range (approx. 1/2 turn before reaching the lock stop). The value determined corresponds to the basic frictional torque (without frictional torque increase). Then, from the straight ahead driving position, rotate the steering gear 1/2 turn to the left and to the right and measure the increase in frictional torque. pecified values for increase in frictional torque (ADP: Automatic High pot Re-Adjustment): without ADP with ADP Type 8051 10...60 Ncm - Type 8052 5...30 Ncm 10...55 Ncm Type 8053/54 5...30 Ncm 10...45 Ncm Type 8055/8076 5...40 Ncm - Type 8073-10...65 Ncm Type 8074/8075 5...30 Ncm 10...35 Ncm Type 8074 with ervotronic 5...30 Ncm 10...35 Ncm Type 8075 with ervotronic 5...30 Ncm 10...35 Ncm If the specified value is not reached, a new adjustment is required. Maintenance, Troubleshooting, Oil-/Filter Change, Disassembly, Assembly 3
Maintenance 2.6 New Adjustment of High pot (Increase in Frictional Torque) for Types 8051...8076 62 27 Rotate the steering gear to the straight ahead position. Loosen the sealing nut (27) and turn the adjusting screw (62) back until there is no more increase in frictional torque (high spot) to be found. Then measure the existing basic frictional torque by slowly rotating the steering gear around mid-position within the straight ahead driving range. Next, adjust the frictional torque increase (high spot) of the steering gear around mid-position. To do so, turn the adjusting screw (62) clockwise until an increase in frictional torque (see table below) as compared with the basic frictional torque is reached. pecified values for frictional torque increase: Type 8051 Type 8052 Type 8053/54 Type 8055/8076 Type 8073 Type 8074/8075 Type 8074 with ervotronic Type 8075 with ervotronic 60...80 Ncm 30...40 Ncm 40...50 Ncm 30...50 Ncm 20...40 Ncm 20...35 Ncm 20...35 Ncm 20...35 Ncm During this adjustment, permanently rotate the steering wheel 1/2 turn to the left and to the right from the straight ahead driving position. Tighten the sealing nut (27) and hold the adjusting screw (62) fast while doing so. Tightening torque: 30 Nm Check again the increase in frictional torque (high spot) thus adjusted. 3 Checking for External Leakproofness tart the engine. Check whether all screwed connections and lines of the steering system and the sealing elements on the steering gear and on the pump are leakproof. Repair leakages, if any. top the engine. 4 Visual Inspection Check all hoses and lines for possible chafe marks and check the bellows and collars for cracks, damages, twisting and firm fit. 4 Maintenance, Troubleshooting, Oil-/Filter Change, Disassembly, Assembly
Troubleshooting II. Troubleshooting 1 Fitting the ZF ervotest Tester Fit the ZF ervotest Tester to the pressure line between the ZF oil pump and the ZF steering gear (see illustration below) at a place enabling a perfect monitoring of the indicating instruments from the driver s seat. Note: The illustration shows a ZF Rack and Pinion Power teering Gear. However, the installation of the tester is analogous for the ZF Recirculating Ball Power teering Gear. For the fitment and operation of the ZF ervotest Tester, please refer to the ZF ervotest Operating Instructions. return line pressure line 2 Checking the Oil Level Note: Prior to removing the oil tank cover, thoroughly clean the oil tank and its immediate surroundings to prevent impurities from getting into the steering system. When the steering system is filled with hydraulic fluid, there is a risk of impurities getting into to steering system. Therefore, to avoid malfunctions caused by foreign bodies in the system, maximum cleanliness is an absolute must during initial fill and during all further topping-ups. Oil grade required: please refer to the lubricants list TE-ML 09 or to the vehicle manufacturer s oil specification. with the engine off: The oil in the oil tank should reach the max. mark. with the engine running: The oil level in the oil tank should be between the min. and max. marks. After the engine was turned off, the oil level may rise by 5 mm maximum. If it rises by more than 5 mm, bleed the steering system. Maintenance, Troubleshooting, Oil-/Filter Change, Disassembly, Assembly 5
Troubleshooting 3 Bleeding the teering ystem teering gear versions with bleeding screw (33)- ZF Recirculating Ball Power teering Gears only: 33 Fill the oil tank with the specified oil (see vehicle manufacturer s instructions or list of lubricants TE-ML 09) to the max. mark. Relieve the front axle by jacking it up. With the engine off, slowly rotate the steering gear twice from lock to lock. Topupwithoiltothe max. mark. Remove the closing cap at the bleeder screw (33) and start the engine. Make sure the oil tank is permanently filled with oil. Then open the bleeder screw by 1/2...1 turn to enable the air to escape. As soon as oil only is escaping from the bore of the bleeder screw (33), tighten the bleeder screw with a torque of 5 Nm. lowly rotate the steering gear several times from lock to lock, making sure not to build up too high a force at the lock stops to prevent the oil from foaming. Note: On vehicles with poor bleeding owing to unfavourable positions of the cylinder line ports, bleeding may take place prior to mounting the tie rods (to the wheel suspension system)/the drop arm. As a larger stroke is now possible, the bleeding operation can be sped up. Check the oil level. If required, top up with oil. Again open the bleeder screw (33) by 1/2...1 turn to enable any further air to escape. Put on the bleeder screw (33) closing cap. top the engine and check by how much the oil level rises in the oil tank. If it rises by more than approx. 5 mm, the bleeding operation described above has to be repeated. 6 Maintenance, Troubleshooting, Oil-/Filter Change, Disassembly, Assembly
Troubleshooting teering Versions with Automatic Bleeding: teering versions with automatic bleeding do not have any bleeder screws. Fill the oil tank with the specified oil (see vehicle manufacturer s instructions or list of lubricants TE-ML 09) to the max. mark. Relieve the front axle by jacking it up. With the engine off, slowly rotate the steering gear twice from lock to lock. Topupwithoiltothe max. mark. tart the engine. Make sure the oil tank is permanently filled with oil. lowly rotate the steering gear several times from lock to lock, making sure not to build up too high a force at the lock stops to prevent the oil from foaming. Note: On vehicles with poor bleeding owing to unfavourable positions of the cylinder line ports, bleeding may take place prior to mounting the tie rods (to the wheel suspension system)/the drop arm. As a larger stroke is now possible, the bleeding operation can be sped up. Check the oil level. If required, top up with oil. top the engine and check by how much the oil level rises in the oil tank. If it rises by more than approx. 5 mm, the bleeding operation described above has to be repeated. Maintenance, Troubleshooting, Oil-/Filter Change, Disassembly, Assembly 7
Troubleshooting 4 Checking the Hydraulic Functioning of the teering ystem 4.1 Checking the Tension of the Drive Belt Check the drive belt tension. Even at maximum pressure within the steering system, the drive belt must transmit the power without any slip. 4.2 Checking the Maximum Pressure/Pressure Relief of the ZF Pump For the maximum pressure indication, refer to the pump nameplate. tart the engine. At engine idling speed, close the shut-off valve of the ZF ervotest tester and read the maximum pressure. Attention: Allow the maximum pressure to act for a short time only, maximum 5 seconds, for otherwise the inner pump components would be heated excessively thus entailing a possible early wear. Turn the shut-off valve back to its initial position. pecified value: Nominal value indicated on the nameplate 10% If the specified value is not attained, repair or replace the pump. 4.3 Checking the Pump Flow Rate At engine idling speed, close the shut-off valve to an extent enabling the generation of the test pressure (see technical data sheet) required for the pump type in question. Read the flow rate (specified values see technical data sheet). If the specified value is not reached, repair or replace the pump. 4.4 Checking the Maximum Pressure and the Leakage Rate of the Power teering For versions without hydraulic steering limitation Build up the maximum pressure in the steering system. To do so, rotate the steering gear to the lock stop or lock it by means of a convenient device. For versions with hydraulic steering limitation Using an appropriate tool, lock the steering gear outside the range in which the hydraulic steering limitation operates (for instance, mid-position). 8 Maintenance, Troubleshooting, Oil-/Filter Change, Disassembly, Assembly
Troubleshooting For versions with/without hydraulic steering limitation Actuate the steering valve to maximum extent and, thereby, build up maximum pressure. Have the engine run at idling speed. Read the maximum pressure at the ZF ervotest tester. Carry our the same measurement as above, but steer to the left. If the pump maximum pressure previously measured is not attained, repair or replace the power steering gear. Read the flow rate (corresponding to the leakage oil rate) at the ZF ervotest tester. pecified value: max.1 dm 3 /min 4.5 Measuring the teering Wheel Play Note: This check can only be carried out for a ZF Recirculating Ball Power teering Gear. Jack the steered axle up. By fitting a locking device, lock the drop arm in the straight ahead driving position of the steering gear. Fit a scale (cf. Chapter VII.) to the steering wheel and fasten the index hand at the dashboard or at the windscreen. tart the engine. Watch the pressure gauge and slowly rotate the steering wheel to the left. When a pressure rise of 1 bar as compared with idle pressure is reached, hold the steering wheel fast and mark the scale value on the scale. Then turn the steering wheel to the right until again a pressure rise of 1 bar is attained. Measure the total travel covered at the steering wheel circumference. pecified value: max. 25 mm If the travel is more than 25 mm, there is mechanical play in the steering box. The steering box must in this case be removed from the vehicle and repaired. top the engine, remove the ZF ervotest tester, top up the oil, put the drag link into place and fasten and secure it. Lower the steered axle down to the ground. Maintenance, Troubleshooting, Oil-/Filter Change, Disassembly, Assembly 9
Oil Change/Filter Change III. Oil Change Note: An oil change will only become necessary after replacing the power steering gear or the pump. 1 Draining the Oil Jack the steered axle up. crew off the pressure and return lines. Have the engine run for approx. 10 seconds and collect the oil that is draining off. Rotate the power steering gear from lock to lock. crew on the pressure and return lines again and close them in a way to make them oil-tight. 2 Oil Filling Required oil grade: see the list of lubricants TE-ML 09 Through the oil tank opening, fill in the oil until the oil level is approx. 1 cm above the max. mark. Next, start the engine and top up with oil to the max. mark. Bleeding: refer to Chapter II. IV. Filter Change A filter change is only required if the oil was changed the power steering gear was replaced the pump was replaced. Remove the filter cartridge from the oil tank and replace it or replace the complete plastic oil tank. Then fill the steering system with oil and bleed it as described in Chapter VI. 10 Maintenance, Troubleshooting, Oil-/Filter Change, Disassembly, Assembly
Disassembly of the teering Box V. Disassembly of the teering Box Attention: The descriptions given below are generally binding and apply to work to be carried out on ZF units. In addition, the vehicle manufacturers instructions must be complied with. Rotate the steering box to the straight ahead driving position. Thoroughly clean the steering gear and its immediate surroundings, in particular the line connections. Jack up the steered axle. crew off the pressure and return lines. Have the engine run for approx. 10 seconds and collect the oil that is draining off. Rotate the steering gear from lock to lock. Close all oil lines (risk of impurities). Loosen the universal joint or the elastic coupling arranged between the steering box and the steering column. Using a suitable tool, remove the tie rods from the wheel suspension system. crew out the mounting bolts and remove the steering gear. Maintenance, Troubleshooting, Oil-/Filter Change, Disassembly, Assembly 11
Assembly of the teering Box VI. Assembly of the teering Box 1 Assembly Attention: The descriptions given below are generally applicable and refer to work to be carried out on ZF units. In addition, the vehicle manufacturers instructions must be complied with. elf-locking nuts, screws, sealing elements and securing elements must be replaced. If the steering gears is replaced following a road accident, also the remaining parts of the steering system, such as tyres, wheel rims, axles, axle suspensions and mechanical connecting parts must be checked for damages (even if there is no visible damage). If required, repair or replace such parts. Interrupt the electric circuit (switch off the ignition and disconnect the negative pole of the battery). Turn the front axle of the vehicle to the straight ahead driving position (the wheels of the front and rear axles must now be in perfect alignment). Check whether the steering box, too, is in the straight ahead driving position (if so, the marks on the steering input shaft/protection cap (if there is any) will coincide with those on the valve housing. Rotate the steering wheel to the straight ahead driving position. Put the steering column on the input shaft of the power steering gear and fasten it (for tightening torques, refer to the vehicle manufacturer s instructions). Install the power steering gear in exactly the same position as in the initial installation and fasten it by means of bolts, nuts, washers etc... (for tightening torques, refer to the vehicle manufacturer s instructions). Fit the drop arm and the tie rods to the steering gear (for tightening torques, refer to the vehicle manufacturer s instructions). Attention:(for ZF Rack and Pinion Power teering Gears only) When tightening the tie rods, the rack must be supported at the spanner flat (do not use any pliers!) for otherwise the inner parts of the steering might be damaged. If there is no spanner flat, no supporting will be required. Connect the hydraulic lines (pressure and return lines). For the tightening torques, refer to the vehicle manufacturer s instructions. 12 Maintenance, Troubleshooting, Oil-/Filter Change, Disassembly, Assembly
Assembly of the teering Box For versions with ervotronic additionally: Insert the converter cable into the converter connection. 2 Filling the teering ystem and Bleeding Fill the oil tank with the specified oil (see vehicle manufacturer s instructions or list of lubricants TE- ML 09) to the max. mark. Relieve the front axle by jacking it up. With the engine stopped, slowly rotate the steering gear twice from lock to lock. Topupwithoiltothe max. mark. tart the engine and make sure the oil tank is permanently filled with oil to prevent a sucking in of air. lowly rotate the steering gear several times from lock to lock and take care not to build up high forces at the lock stop to prevent the oil from foaming. Note: On vehicles with poor bleeding owing to unfavourable positions of the cylinder line ports, bleeding may take place prior to fastening the tie rods (to the wheel suspension system)/the drop arm. As the stroke available is now larger, the bleeding operation can be sped up. Check the oil level, if required top up with oil. By visual inspection, check the steering system (steering gear, cylinder lines and connections, oil pump) for leakproofness. top the engine and check by how much the oil level rises in the oil tank. If it rises by more than approx. 5 mm, the bleeding operation described above has to be repeated. 3 Checking the Front Axle Geometry Check and adjust the front axle geometry in accordance with the vehicle manufacturer s instructions. Maintenance, Troubleshooting, Oil-/Filter Change, Disassembly, Assembly 13
pecial Tools VII. pecial Tools Ordering Reference ZF-ervotest 570 tester 7418 798 570 cale with index hand 7418 798 452 Additional tool for ZF Recirculating Ball Power teering Gear Types 8051...55 and 8073...8076 Torque meter 7418 798 706 Clamping range: 350...500 mm 14 Maintenance, Troubleshooting, Oil-/Filter Change, Disassembly, Assembly
Inspection Report ZF Rack and Pinion Power teering Gears and ZF Recirculating Ball Power teering Gears Order No.:... Date:... Version ref.:... Mfg. ref.:... Mfg. date:... Maintenance Work 1 Maintenance intervals: after 50,000 km, each 2 Checking the Mechanical Functioning of the Power teering Gear Fit of the mounting bolts checked: j yes traight ahead driving position checked: j yes Play of the steering column checked: j yes Angular play and stiff operation between upper input shaft and steering box checked: j yes High spot adjustment checked (ZF Recirculating Ball Power teering Gears only):j yes 3 Checked for External Leakage: j yes 4 Visual Inspection: j yes 5 Fitting the ZF ervotest Tester: 6 Oil Level Checked: j yes 7 teering ystem Bled: j yes 8 Checking the Hydraulic Functioning of the teering ystem Drive belt tension checked: j yes Maximum pressure/pressure relief of ZF pump:... bar Flow rate of ZF pump: peed... r.p.m. Pressure... bar Flow rate... dm 3 /min Original for duplicating Maximum pressure of power steering gear: Leakage rate of power steering gear: teering wheel play: Test drive carried out:... bar... dm 3 /min... mm j yes Examined by:... Date:... Maintenance, Troubleshooting, Oil-/Filter Change, Disassembly, Assembly 15
Notes 16 Maintenance, Troubleshooting, Oil-/Filter Change, Disassembly, Assembly