This is not an advertisement and I am in no way related to the company that sells the Whale Pumps but I like to acknowledge their fair behavior.

My Whale Gusher 10 MK3 pump bought about 5 years ago developed severe corrosion inside the body.
The alloy was exposed and corroded around the discharge valve and the yellow coating had small blisters in several parts of the internal surface. I contacted the company through their web site asking for advice and few days later a nice guy of the Customer Service replied this:

"I am sorry that you have experienced this problem with the Gusher 10. We pride ourselves in the highest quality manual bilge pumps and you have not experienced this. We would like to replace your pump under warranty even though the product is just outside of its warranty period. Can you please fill in the attached form... etc."

I did and yesterday, about ten days after my first letter, I received the pump sent by courier from Ireland to Italy.

Nowadays it is not a common behavior, I am afraid.