I recently became aware of the rear wiper on my F25 not parking correctly. Sometimes it was too far up the screen, other times it would go on to the tailgate panel.
On investigation, the plastic part near the pivot had cracked. So I ordered a replacement arm and blade. These aren't OE BMW, but "OE-quality" - Febi, to be precise. But I digress.
When I removed the nut from the pivot, the wiper arm fell off - leaving behind the splined aluminium insert. This had not only swollen causing the crack in the plastic, but it was so badly corroded onto the steel(?) pivot that the only way I could get it off was to cut four slots into it with the Dremel that I use for model-making. I actually knackered a nearly-new wiper arm puller trying to get the insert off the pivot.
The offending wiper arm appeared to be the one that was fitted from new. Interestingly, the Febi one uses a brass insert.
Those of you with older cars might want to lift the pivot cover on the rear wiper arm and check the condition of that pesky aluminium insert.
