Is the Release Button replaceable, mine needs hard pushing to focus. Ihave2bodies

Hi, the release button on my d70 isn't good anymore. It needs hard pushing to focus, often making the picture without correct focus. I have a spare body with other defects. Is the button easily replaceable? Taking off the top cover would be a pain and a no-go for me. Or is the problem not within the button but within the body?

Thanks for answering.