ZF INDEPENDENT WHEEL SUSPENSION RL 55 EC 5871.201.922 en
Preface This documentation has been developed for specialized staff trained by ZF Friedrichshafen AG for repair and maintenance work to be done on ZF units. Due to the continuous technical upgrading of the product, however, the maintenance of the unit at your disposal may require both deviating work steps and differing setting and testing data. These operating instructions are based on the unit s state-of-the-art at the time of printing. They were prepared with utmost care in order to avoid errors. ZF Friedrichshafen AG, however, shall not be liable for any possible errors in figures or descriptions. ZF Friedrichshafen AG reserves the right to replace these operating instructions by a successive edition at any time without advance notice. Upon request ZF Friedrichshafen AG will advise which edition is the latest one. The owner and the user shall be responsible for complying with the safety instructions and for implementing any maintenance work according to the specified guidelines. ZF Friedrichshafen AG shall not be liable for any incorrect installation, improper handling, insufficient maintenance, improperly and incompetently performed work and any consequential damage resulting thereof. It is imperative to observe the relevant instructions and manuals of the vehicle manufacturer. Important information regarding technical reliability and operational safety are highlighted by the following symbols: INFO CAUTION DANGER This symbol serves as a reference to special working procedures, methods, information, use of auxiliaries etc... indicated in these operating instructions. This symbol identifies situations in which lacking care might lead to damage to the product. This symbol identifies situations in which lacking care might lead to personal injury. ZF Friedrichshafen AG ZF Services Donaustr. 71 D - 94034 Passau Dept.: MAIP21 Copyright ZF Friedrichshafen AG. This document is protected by copyright. Complete or partial reproduction or dissemination of this document is prohibited without the consent of ZF Friedrichshafen AG. Infringements lead to civil and criminal prosecution. This document is a translation of the German original. Subject to technical modifications! Design level 2012/04
1. Grease lubrication of hub bearing The hub is fitted with a completely sealed compact bearing, which needs no maintenance under normal driving conditions. The bearing is filled with lifetime grease, so that lubrication is unnecessary Disassembly of the wheel bearing is not required when changing the brake disk Disassembly/reassembly of the wheel head does not required an adjustment of the bearing clearance To ensure proper function of the wheel bearing during the vehicle s service life, it is recommended to check it for immaculate condition at regular intervals during service and repair work to identify any defects or relating damage mechanisms in due time. 1.1 Inspection/check Inspect/check the compact bearing during service and repair work. 1.1.1 General The following inspections/checks are required: Axial play of compact bearing Bearing noises Bearing seal (grease leakage) These inspections/checks help to analyze the following error sources in due time: Fatigue of bearing Bearing failure due to o Insufficient lubrication because of grease leakage o Insufficient lubrication because of malfunction of sealing (water entry or corrosion) o Insufficient lubrication because of thermally over-stressed grease o Loss of preload due to excessive axial play, caused by wear or setting phenomena 1.1.2 Inspection and checking routine Inspections/checks Test Axial play Noises Tightness Comments Change of brake lining x x x Change of brake disk x x x Change of tires x x SP-brake test* x x Safety test ABS-error message x x Excessive play Damage to suspension x x Damage to rims x x Steering wheel wobble x Overheated brakes x Vehicle Inspection x x x annual Vehicle Inspection x x x > 1 million km * Safety test acc. to BGBL (Federal Law Gazette) I, S.1051 for Germany! Strict observance of the relevant national regulations in all other countries is imperative! 5871.201.922 en 1
1.2 Check of axial play Jack up the vehicle and push the brake linings off the brake disk Fix a dial indicator to the steering knuckle and place it at right angles to the brake disk (1) Determine the axial play by pulling and pushing the wheel or wheel flange (2) in axial direction The dial indicator measures the motion of the brake disk (1) in pulled or pushed condition The difference between both measurements equals the axial play Repeat measurement three times and determine average value o After each check, rotate wheel in both directions If axial play exceeds 0.10 mm (in new condition, axial play is < 0.0 mm) o Check tightening torque of central nut and readjust, if required o Then repeat measurement If measured value is confirmed, replace bearing unit Any operations or setting values required for disassembly and reassembly are included in detail in the relating repair manual (5871 201 202)! Check of axial play Check of bearing noises: 1 2 Figure 1 Figure 2 1.3 Check of bearing noises Damage due to fatigue of bearing produces vibrations from a significant size onwards. These can be heard as a noise, or felt as a "rough run", respectively. For a clear identification carry out the following check: Jack up vehicle, do not remove wheel, and push brake linings off the brake disk Quickly and slowly rotate the wheel or wheel head manually in both directions, at the same time applying a moment of tilt in axial direction Replace bearing, if it feels rough or if grinding noises are produced Noise frequency rising with the wheel speed indicates a bearing damage, grinding noises could also be produced by tight-fitted brake linings (push brake linings off the brake disk). Repeat the check! Any operations or setting values required for disassembly and reassembly are included in detail in the relating repair manual (5871 201 202)! 5871.201.922 en 2
1.4 Bearing seal (grease leakage): Regarding damage, check the internal seal (at side of steering knuckle) for grease leakage (e.g. overheating of brake disk ) o Grease leakage through the gap area on the protection sheet indicates a defective seal o In that case, replace wheel bearing Figure 3 Little grease leakage at outer seal (slight grease collar) is permissible (see figure 5) o Check is only possible with removed wheel flange (disassembly of brake disk) o In case of heavy grease leakage or even entry of water, replace wheel bearing (see figure 6) Figure 4 Figure 5 Figure 6 1.5 Visual check of material/heavy operation In case of excessive heat, metal parts might discolor - "tempering colors" as they are called. Check whether the clearly visible pressure plate, hexagon nut and wheel hub can still be used. Wheel bearing unit must also be replaced in case of a sluggish wheel head, i.e. if the drag torque is > 15 Nm. 5871.201.922 en 3
2. Grease lubrication of steering knuckle /control arm/steering lever/relay lever 2.1 Grease quality Approved greases for the ZF-independent wheel suspension RL 55 EC see ZF List of Lubricants TE-ML 12. The ZF list of lubricants is being continuously updated and can be obtained or viewed as follows: in all ZF plants in all ZF Service Centers Internet: http://www.zf.com A lithium-saponified multi-purpose grease of NLGI class 2 which is mixable with mineral oil (grease code KP2K-30 acc. to DIN 51825 or ISO-L-XCCHB2 acc. to ISO/DIS 6743-9) is to be used at the greasing points. 2.2 Grease interval Grease the described components each after 80,000 km or once per year, whichever occurs first. 2.3 Position of lubricating nipples 1 = Steering knuckle bearing (top) 2 = Steering knuckle bearing (bottom) 3 = Control arm bearing (top) 4 = Control arm bearing (bottom) 5 = Steering lever 1 3 3 5 1 2 4 4 2 Abbildung 7 Lubricate the greasing points with a grease gun until grease comes out at the seal rings (steering knuckle bearing) and scrapers (control arm bearing)! 5871.201.922 en 4
3. Wheel bolts and wheel nuts We would recommend you to replace heavily corroded wheel bolts. For tightening torques see vehicle manufacturer. Please take further information from our Service Information in the ZF-Service-Line. Never grease/oil the thread of wheel bolts and wheel nuts. 4. Lifting jack points Do not position the lifting jacks on other points than those marked in red in the following illustration: Figure 8 5871.201.922 en 5