new-kid

Recently had the drivers wiper arm fail with a bang - whilst travelling on a motorway at speed in the rain.

Managed to stop safely. And then continued intermittently in the dry spells.

When called out BMW assistance the first question was "have you had the windscreen replaced recently"?
I had (not by a BMW dealer as the insurance wouldn't cover this). The repair was as two minute job, just tightening the nuts on the lever arm.

However, it had never occurred to me to tighten the nuts. Every other car I have owned the wiper mechanism works by splines on the shaft and wiper arm. This mechanically sound arrangement only needs the screw/nut to hold the wiper on the splines, which take the torque. Are BMW wiper arms so badly engineered they rely on the nut tenson for grip ?