Pittsburgh ? Mike Webster’s durability and toughness made him a four-time Super Bowl champion and one of the NFL’s best linemen ever. Those very qualities also might have led to a brain injury that sent him spiraling into drug use and homelessness.

The bare-armed strongman nicknamed “Iron Mike” died Tuesday at 50. He was remembered as a great center whose sturdiness personified the Pittsburgh Steelers’ championship teams and whose off-field health and drug problems saddened them.

The Pro Football Hall of Fame lineman died in Allegheny General Hospital’s coronary care unit. At the request of Webster’s family, the hospital did not release the cause of death.

The Steelers initially said Webster died of a heart attack but later declined to comment. Webster was diagnosed with brain damage in 1999, an injury caused by all the years of taking shots to the head.

“He was one of the main reasons why we won four Super Bowls,” Hall of Fame running back Franco Harris said. “Unfortunately, he had some turmoil and misfortune after his football career. He is now at peace.”

Chosen as the center on the All-Time NFL team in 2000, Webster found his life after football the opposite of his disciplined, overachieving 17-season NFL career.

Bothered by debt, depression and bad health, he separated from wife Pam before his Hall of Fame enshrinement in 1997 and was homeless for a short time, living in his pickup truck. He was placed on probation in Beaver County, Pa., after pleading no contest in September 1999 to forging prescriptions to obtain Ritalin, a drug commonly used to treat children with hyperactivity.