Are medical providers required to respond to your request for medical records once you provide a copy of the SSA 827 to them? Is eliciting cooperation from them generally an issue for case managers?

Generally speaking, medical providers are not legally bound to provide records to a third party. They are not required to provide records to DDS, either. However, HIPAA regulations require healthcare providers to provide individuals copies of their own records: 

"The Privacy Rule generally requires HIPAA covered entities (health plans and most health care providers) to provide individuals, upon request, with access to the protected health information (PHI) about them in one or more “designated record sets” maintained by or for the covered entity.”

We hear from most SOAR providers that they are able to get medical records from most sources. Some states have special laws that cover access to records for disability applications. We also do our best to build relationships with commonly used providers and the medical records departments to try to improve those relationships, and clarify and expedite processes.