They were discovered by a member of the public on Monday, May 27.
Mr Hynard, 58, was last seen at home on Tuesday, March 1, 2011. His silver Honda CRV, was found in The Avenue, Brockham two weeks later.
Mr Hynard lived in the area until the early 1990s and knew the area well.
Mr Hynard suffered a serious back condition and was taking medication that his teacher wife, Stephanie Lord, said caused depression, memory loss and disorientation.
The death is currently being treated by police as unexplained and Mr Hynard's next of kin have been informed of the discovery.
Surrey Police said the remains were being DNA tested to ascertain whether they were that of Mr Hynard. They are preparing a file, which will be passed to the coroner.