SEBO C 3.9 x 22 Screw, DIN 7981, for the 370 ELECTRONIC and ET-C Power Head — Single

Ordered by designation rather than by eye: part 174 is the C 3.9 x 22 screw to DIN 7981, the fastener SEBO specifies in the 370 ELECTRONIC upright and in the ET-C power head. It is sold as a single screw.

DIN 7981 describes a self-tapping pan-head screw, the type that forms its own thread in a moulded boss rather than meeting a nut. That detail matters when you are choosing a replacement, because a machine screw of the same nominal size will spin uselessly in the same hole. The 3.9 is the diameter and the 22 is the length, and at this position both have to be right — too short and it never reaches the boss, too long and it bottoms out or pushes through.

• Fits: the SEBO 370 ELECTRONIC and the ET-C power head
• Size: C 3.9 x 22
• Standard: DIN 7981
• Head: cross-recess pan head, self-tapping
• Pack: one screw
• Order as: SEBO part 174

Fastenings inside a power head live a hard life. They take heat from the brush motor, constant vibration off the roller, and repeated removal every time a belt is changed or a jam is cleared, so sooner or later one strips its boss or shears off in the hole. If the head has been apart several times it is worth ordering a couple of spares alongside whatever else you need, since a missing screw at this position leaves the housing able to flex.

Keep the screw you removed until the new one is in and tight. If the boss it threads into has cracked or its walls have split, a fresh screw on its own will not solve anything, and that is far better to discover with the head still open than after everything has gone back together.

Anyone searching for a SEBO 370 ELECTRONIC screw, an ET-C power head screw or a genuine DIN 7981 3.9 x 22 will find it here. Hold it against the screw you removed to confirm the length before driving it home. Genuine SEBO hardware from an authorized dealer.