I have had this failure several times and here is a cheap way of resolving the problem on a temporary or long term basis. A 2mm steel drill bit, a large washer and a split pin will be all that is need. Remove the wipers and fascia and the wiper assembly will come out easily. Drill a 2mm hole through the linkage pin, lubricate the assembly and reassemble adding a washer and insert the split pin the ensure washer is retained. Should take between 15 mins and half an hour to get your wiper back in action. A Picture sequence is below.