wipers

Johnno, In all instances of my Alfa Romeo wipers, that by the way are operated by linkages not a cable as Dino, it was a matter of opening up the motor, washing the parts in alcohol,
sanding the commutator with 1000 grit wet s.paper.
This, chuck on a drill and spin, very easy!

Then re-lube the top and bottom bushings, and you should be good as new.
Possibly the cable can be slipped out and given the above clean/lube.
Last, clean where the wiper arm pivots spin inside the housings, and lube.
The brushes should be still good, but easily replaced.
There could be relay issues, but to me that's another galaxy.

Regards, Alberto

 

Before you go to that much trouble.
1 check voltage drop at wipers
2 make sure the rheostat that controls the wiper speed is functioning, best way is to by-pass the rheostat completely
3 proceed to commutator cleaning

clay

 

Another trick is to use RainX on the windshield to make the wipers glide over the glass with less friction. The factory wiper system was weak to start with so any help speeds them up.