Hi Our R22 is showing the same signs of corrosion it is due to a reaction with incorrect self etch primer proir to painting (machine less than 3 years old). I also know of a less than 2 year old R44 with the same problem. The Distributor tried to say it was down to the area in which its used which is a load of bollock! Does your Bentley Or Aston have to have a different coat of primer for use in damp conditions? I think not likewise If your Bentley or Aston developed this type of corrosion you would play balls with the dealer Not the manufacturer additionally all the dealer would do is put in a warranty claim. I think we are being shafted here? There is something in the sale of goods act which says " Fit for the propper purpose for which it was intended" More people should shout a lot louder about this afterall its these people that are making the dealers (Worldwide) and the manufacturer a lot of money by spending their $$ with them. Isnt the customer right? well some of the time anyway