On the gearbox itself, all ball bearings are removed and replaced by ball bearings from SKF with polyamide cage. The reason for the replacement was a slightly rough running noise of the original bearings and the quiet running of the polyamide cage bearings. Unfortunately there are no pictures of this.
For the screwing of my gear unit I use countersunk head screws with internal multi-tooth similar to DIN 965 made of stainless A4 steel. This steel has a tensile strength of only 700 N/mm², which is still higher than the tensile strength of an A2 screw. It is a widespread misconception that stainless steel screws are more durable. A “normal” 8.8 screw has already a tensile strength of 800 N/mm², but is not resistant to corrosion. The screws are lubricated with Loctite 8065 Anti-Seize. These circumstances result in new values for the required tightening torques. In the workshop manual a tightening torque of 8-12 Nm is specified, this specification is now useless. In order to determine the exact tightening torque, one would have to know the total friction coefficient of the new screw connection, which would require extensive testing. From various tables it can be seen that the tightening torques are significantly lower than those of conventional 8.8 steel bolts due to the lower friction. Therefore I tighten the screws with the lowest stated torque from the repair instructions.
Another attack on my wallet is a torque wrench Torcofix-K from Gedore for a range of 5-50 Nm. The torque wrench is delivered calibrated with a calibration certificate. The 3/8″ tools are actually a pleasant intermediate size.
The shift forks are the first wear parts to be measured. These run on the gear wheels and push the corresponding gear wheel pairs back and forth during shifting. The permissible width is 3.8mm – 3.9mm or 5.3mm – 5.4mm. The dimension of the shift forks was measured with a micrometer, the shift forks were all below these dimensions and will be renewed.
|5x Countersunk head screws with Torx like DIN965 A4 M6x16||2,56 €|
|2x Countersunk head screws with Torx like DIN965 A4 M6x30||1,58 €|
|4x Lens head screws with Torx like DIN7985 A4 M6x12||2,36 €|
|Bearing SKF 6202 TN9 C3||5,73 €|
|Bearing SKF 6304 TN9 C3||17,29 €|