On my 280SL 1970 the washer fluid pump / motor did not work. So I decide to take it apart and see if I can fix it before replacing it. My assumption was there would be a broken wire on the brushes or some other relatively simple fix. I managed to fix it and it had two problems.
1. The gears / pump were very stiff to turn. I managed to take this apart and lubed it up and this made them turn very easily.
2. The motor would not work because the brush spring mechanism stopped contacting the commutator bar. I fixed this by stretching the spring slightly and slight bend to the arms where the brushes are mounted. The hardest part is because this motor is sealed, it had to be taken apart by carefully using a coping saw or similar small saw, cut the end of the housing. I will need to glue it back before I fit it back in the car but i tested it and it is working very well. I hope this helps someone to keep the original motor. I attach a picture of the motor and gears / pump so that you cans see what is inside.
