Wheels - New Torque & Guidlines for Mounting Disc Wheels
83mercedes02TO: OUR MERCEDES-BENZ PASSENGER CAR DEALERS
DATE: March, 1983 (supersedes 40/37) REF. NO. 40/45
SUBJECT: MODIFIED TIGHTENING TORQUE AND GUIDELINES FOR MOUNTING DISC WHEELS
The nominal tightening torque for the wheel bolts of disc wheels has been slightly increased (except for model 600).
Model Tightening torque
of wheel bolts
All models 110 N-m
(except model 600)
600 170 N-m
Guidelines for Mounting Disc Wheels
1. Wheel bolts should always be tightened using a torque wrench. We recommend that the torque wrench be checked regularly.
2. The mating surfaces of the disc wheel, the front wheel hub, and the brake rotor must be clean. Clean corroded surfaces with a wire brush or a piece of emery cloth.
3. Only use wheel bolts that turn easily in the threaded hole. Bolts that are hard to turn or are corroded at the spherical collar or thread should be replaced.
4. The threads in the front wheel hub and rear axle flange should not be tight. Tight threads should be re-tapped.
5. The hub flange and wheel bolt seats in the rim must not have any damage. Wheel and hub mating surfaces must be clean.
CAUTION: Dirt or corrosion on the mating surfaces, especially on light alloy disc wheels, as well as tight threads, can have a negative effect on the pre-load of the mounted wheel. Since the dirt or corrosion settles after tightening, the necessary preload is not obtained due to high friction. If the preceding guidelines are not followed, the wheel bolts can become loose, even if the proper tightening torque is applied.
In addition, the brake rotor must be kept from moving off the rear axle flange during repair work (for example, replacing brake pads). If this happens, dirt particles and corrosion can get between the rear axle shaft flange and brake rotor.
If new axle components are installed (brake rotor, front wheel hub or rear axle flange), the mating surfaces of the axle components remaining on the vehicle should be carefully cleaned.
When new disc wheels are installed for the first time (spare wheel or a set of winter tires) the wheel bolts must be re-torqued after 100-500 km (60-300 miles).