Checking Alignment of Rear Shock Absorbers
Checking alignment of rear shock absorbersPreliminary work: R and R rear shock absorbers. Refer to Service and Repair Service and Repair
For vehicles equipped with rear level control refer to Spring Strut Suspension Strut / Shock Absorber
013 Testing and straightening tool
013a Straightening bolt
013b Testing and straightening pin
013c Test sleeve
013e Washer
013f Hex. nut
72 Semi-trailing arm
76 Dome on frame floor
Special tools
Note: Extremely high deviation in the alignment of the shock absorber mounting points can lead to excessive shock absorber or spring strut wear resulting in rumbling noises and leakage at the piston rod seal. In extreme cases this can even negatively affect the driving comfort (suspension harder due to increased friction).
For this reason it is necessary to check and, if necessary, correct the shock absorber alignment following straightening and repair work on the affected rear end frame parts. The shock absorbers can be checked for proper alignment with the axle installed with the vehicle in the design position.
The previous testing and straightening tool for checking the shock absorber alignment on the rear axle, part no.107 589 00 21 00 has been replaced by the new testing and straightening tool 123 589 O5 21 00 which can be used for both the front and rear axles.
CAUTION! When removing the shock absorbers with the vehicle jacked up and load relieved on the suspension ensure that the piston rod does not turn while loosening the top mount. Since the extension stop in the shock absorber is against the operating piston in this state, the connection between the operating piston and piston rod could loosen. This would result in sudden extension of the piston rod and expulsion of the oil in the shock absorber.
Checking
1. Load rear end of vehicle until specified vehicle level is reached.
013 Testing and straightening tool
013a Straightening bolt
013b Testing and straightening pin
013c Test sleeve
013d Test plate
013e Washer
013f Hex. nut
013g Arresting screw
2. Fasten testing and straightening tool to top mounting point for shock absorber after removing arresting screw (013g).
013 Testing and straightening tool
013a Straightening bolt
013b Testing and straightening pin
013c Test sleeve
013e Washer
013f Hex. nut
72 Semi-trailing arm
76 Dome on frame floor
3. Check alignment with test sleeve (013c). When the gap between the semi-trailing arm and test sleeve (see arrow) is the same all the way around, this indicates a deviation of 0 mm. To correct remove test sleeve and use testing and straightening pin.