As the blade doesn’t go up into the corners, as it should, confirms that the coged wheel (picture) is slipping on its shaft.
I wouldn’t tack weld the rods as you could still fix the coged wheel with a roll pin at some later date.
The shorter blade is serving its purpose, I would stick with the 21 inch blade, that issue is of less importance as it won’t stop the wipers working.
As you are able to move the blade by hand, indicates that the nylon gear teeth have been striped, that would explain the parking of the blade in the wrong location on windscreen. Remove the 7 bolts on the motor gearbox and I think you will find nylon shavings present, (picture) if that is the case, its replacement motor time.
The rest of the mechanism at the back should be ok, the only thing that can fail on it is the ball joint socket (picture). which can be worn away because of a lack of lubrication or Nut 1 or Nut becoming loose.
MB dealers usually won’t replace the motor on its own without the mechanism however the motor can be got for around £70? elsewhere, others may advise.
Dec
