The Brazilians confirmed the signing on their official website.
The 30-year-old joins Sundowns on a free transfer after leaving Spanish second-tier side Cordoba.
“Razak, who has played for the Ghana national team, and played in the epic Africa Cup of Nations final against Ivory Coast which Ghana lost 9-8, has joined the Brazilians on a five-year contract,” read a statement on the club’s website.
Brimah will be competing with Denis Onyango and Kennedy Mweene for the number one spot at Sundowns.
Meanwhile, Sundowns are said to be considering retaining Thela Ngobeni. The 28-year-old shot-stopper spent last season on loan at Free State Stars last season.
If retained, Ngobeni will be the fourth-choice goalkeeper at Sundowns.
— Mamelodi Sundowns FC (@Masandawana) 1 August 2017