Windshield wiper sticking

Thanks, I have oiled every joint I could when putting the darned thing back together for the second time but no joy. It was not exactly a new motor, the first time I stripped it it looked like it was not gripping a cog properly so I cleaned it up and fettled it but it still did the same thing. So I bought a scrap motor from a Mondeo as I thought they'd be the same as its same chassis etc, as Jag but the housing on motor was opposite way round so I had to take out the innards and swap it into Jag motor wiper, which worked fine for a few days but now back to square one. The thing is I live in Highlands of Scotland and there are not many car spares places and I very been quoted over 300 quid for a new one, which I just cannot afford. And it is snowing. So I am wondering if I am wasting time and money buying new motors if its another issue altogether. I have not had wipers like this on any other vehicle so I dunno really.