I've torn down all the winches and serviced them, replacing the pawls and springs from a Barient parts supplier in Australia: Australian Yacht Winch Company
Barient winches are no longer sold, serviced, nor are parts readily available, so this supplier is a goldmine. I bought several spare pawls and springs.
The Nonsuch owner's manual details the servicing of the winches, but essentially you must work slowly and carefully, do not put grease on the pawls, and do NOT try to do the work on the boat...lots of little parts can go missing.