Wiping the Air!

[myoldjalopy]

Very, very occasionally, the wiper on my SII flips over the outer edge of the screen and begins wiping the air! If I simply push it back into position, its OK again for a long time.
Probable cause and solution please, peeps.....

[Peted7202]

Have a look at the video. Seems it may just be coming off the clips.
https://www.youtube.com/watch?v=jf5x0s35gHI

[myoldjalopy]

No, its not as simple as that - the actual passenger side wiper arm seems to somehow slip about 90 degrees clockwise (facing the front of the car) so that its parked position is almost verticle at the outer edge of the windscreen, and wipes fresh air beyond the window edge when in operation.....thus contradicting my trafficator when I signal right!

[svenedin]

Error: double post

[svenedin]

Are the splines that the wiper arm locates onto worn? I don't know whether that part is available separately but the whole wheel box is available from ESM.

[JOWETTJAVELIN]

Are the slotted head screws at the wheelbox inside the car tight. I had problems with my Series II passenger side wiper until I tightened these.

[Peted7202]

Have a look at this. Could be slipping on drive spiral

Windscreen Wipers.jpeg (681.15 KiB) Viewed 744 times

[JOWETTJAVELIN]

Oh yes, that happened too, the cure was to shim the spindle with brass for a tight fit.

[myoldjalopy]

Thanks all. Slipping cog on the drive cable or the blade arm slipping on the splines do seem like possibilities.
JJ - are the screws you mention visible in the diagram posted above?

[philthehill]

If the cog/spindle (item No: 17 in doth diagrams above) is worn turn the cog/spindle 180 degrees to get onto unworn teeth. Had to do that with my Ser 2.

[JOWETTJAVELIN]

Thanks all. Slipping cog on the drive cable or the blade arm slipping on the splines do seem like possibilities.
JJ - are the screws you mention visible in the diagram posted above?

Yes but the glove box will have to be removed first.

[myoldjalopy]

OK, but which ones are they? Are they numbered in the diagram?