Really hope someone can suggest the cause and a solution here, because this issue is doing my head in. Before winter my rear wiper blade was looking tatty, so I replaced all three. Simple maintenance, never had an issue before. Since fitting (all Bosch, bought at Halford), the driver side blade only has come loose 4 times at standard or high speed, once town centre driving and 3 times on the motorway, including very poor weather on a city centre flyover.

Examining it, the blade apparently slides back (ie not locking into position), then catches and flings sideways. I've been hyper alert, so haven't actually lost one off the car - yet. At first I thought it was a faulty unit, but I've tried 3 units now, and the problem is consistently on the driver side. Can't see what the problem could be on the wiper arm; it's a basic j hook. 

I've run the wipers parked, and no sign of either blade catching anywhere. Both are the right size for driver and passenger side. 

Anyone out there experienced this? Or has Bosch gone for cheaper unit production in the last year? Thanks in advance!

 

I cannot see the plastic adapter that connects the wiper to the arm in any of your pictures - is it there and is the correct one for the arm eg not teh smaller option taht comes with this blades?

@Jay762 looks like you identified the problem - Thanks! 

 

The removable centre part (adapter) of the new Bosch blade unit I fitted looked like this:

 

But on older units, looked like this:

 

So, the fins, and small square block in the centre, ensure the blade clicks into the wiper arm properly. I managed to get a couple of these from a local auto-parts which keeps a box of them. So for any other newbie with this problem - try your local auto-parts - or make sure you keep the adapter part when you ditch an older worn blade unit.

 

 

Result 👍