ZF training at Stahlgruber

ZF training at Stahlgruber

BY PHILIPP BEDNAR

“Because defective DMFs are almost never due to material errors, but rather assembly or diagnostic errors.”Matthias Raufeisen, technician at ZF Friedrichshafen

Modern cars are great: economical, more environmentally friendly and low in noise and vibration. One component of the drive train, the dual-mass momentum, is particularly responsible for the latter. The DMF takes care of keeping disruptive torsional vibrations away from the passenger compartment at low speeds and thus minimizing frequency interference. Crucial point: The dual-mass flywheel is more complex than a normal flywheel, making it more expensive and more susceptible to wear. Matthias Raufeisen, a technician at ZF, explained the pitfalls of the DMF during a product training session at the Stahlgruber sales store in Ried im Innkreis: "Every complaint is checked by us. We reject almost all of them. Why? Because defective dual-mass flywheels are almost never due to material errors, but rather assembly or diagnostic errors." As a rule of thumb, Raufeisen says that the DMF has approximately the service life of a clutch. Under normal circumstances. If the dual mass flywheel lasts significantly less time, it is important to investigate the cause. The professional’s first question: “Is the car chipped?” Because ZF manufactures its DMF under the Sachs brand name strictly according to manufacturer requirements. Tuned vehicles - especially turbodiesel engines are often optimized - then produce more torque and power and can therefore be too powerful for the original dual-mass momentum and clutch. Driving at too low a speed is also bad for the service life, says Raufeisen.

PRECISE CONTROL

In order to be able to check how a DMF works, it must be at operating temperature. "Grease is used in the dual-mass swing. It only becomes supple at operating temperature," says Raufeisen. When installed, the DMF can be checked as follows: Drive at very low speed in second or third gear just before stalling and briefly give full throttle. If you hear a rattling noise from the clutch area, this can be the first indication that the dual-mass momentum is dying. When removed, the DMF should be able to be turned by one to two centimeters by hand. If that doesn't work, the DMS needs to be checked more closely. Other causes for defective dual-mass swings can be screws that are too long or incorrect during installation, or a starter that is too weak, for example due to battery voltage that is too low. ZF specifies that the starter must perform at least 300 revolutions per minute in order to operate the DMF without damage. Broken springs, grease leaks and overheating areas are classic damage patterns. The two-hour training session did not bore the 30 guests with theory, but rather gave them some practical tips and tricks for everyday workshop life. Colleague Peter Seipel will also take up the topic of dual-mass momentum in one of the upcoming diagnostic crime novels.