Porsche 996 TT, Repair Manual

Page: 353 / 2099

Affix balancing weights on the outer plane (uniform procedure / could also be distributed or affixed on the
inner plane). Under no circumstance remove the weights affixed during stationary balancing. Mark the
balancing weight required by electronic fine balancing using a prick punch in order to distinguish it.
Read out and erase the PSM fault memory after fine balancing.
Further to 4a: Fine balancing of the front wheels
Note
Due to the all−wheel drive, all four wheels must be raised and must be able to turn freely. •
Ensure that the take−up fork of the measuring support does not damage any parts! •
Position measuring support at the front axle on the right and left. Before the first measuring run,
re−check to ensure that slipping from the measuring support is not possible!
Centre the sensitivity control. Carry out a measuring run.
Affix balancing weight if necessary. Then perform a check run. If the result is unacceptable
(precondition: the work was performed properly), calibrate the finish balancer. This means that the
sensitivity control must be adapted to the actual situation.
If the balancing result is still not quite right even after calibration (for example, 5 g), change the
balancing weight according to the balance correction table (balance correction schematic) and
thereby eliminate the residual imbalance.
Further to 4b: Fine balancing of the rear wheels
Note
Due to the all−wheel drive, all four wheels must be raised and must be able to turn freely.
•
Do not damage any parts with the take−up fork of the measuring support! •
Position measuring support at the rear axle on the right and left. Before the first measuring run, re−check
to ensure that slipping from the measuring support is not possible!
Set the sensitivity control to 3...3.5 (depending on the equipment version). This corresponds to approx. 1/3
of the max. sensitivity.
Perform measuring run at a speed of 130 km/h or 1,150 to 1,200 rpm (wheel revolutions) in the highest
gear. Affix the corresponding balancing weight.
Perform a check run. Calibrate the finish balancer if the balancing result is unsatisfactory. This means that
the sensitivity control must be adapted to the actual conditions.
Then (in the case of a good balancing result) slowly increase the speed to 190 km/h and carefully observe
at what speed vibration can be felt at the steering wheel and/or seat again (mainly at 175 +/− 5 km/h).
Maintain this speed and re−balance the wheels in the same way as at 130 km/h. Do not affix any
new weights; instead, improve the wheel running smoothess by changing the existing weights
according to the balance correction schematic.
einordnung
Further to 4: Electronic fine balancing 290