Took of my rear wiper motor today. I checked there was power going to it but the spindle was seized solid. I removed the plastic cover from the gear housing and everything was well greased. I then used my chef's blow torch to heat the plastic sleeve around the spindle. It will take a fair bit of heat. Whilst hot I sprayed WD40 into it from the gear end. Twisting the shaft with plyers it immediately freed up. That's forty quid saved!