After leaving The Red Devils, Brewer formed another band named the Jazzmasters for whom he played drums and sang.

[3] In 1968, Brewer left Terry Knight and the Pack along with bandmate Mark Farner and recruited Mel Schacher, the bassist for the hit band ?

In addition to playing drums for Grand Funk, Brewer also provided lead vocals for a number of songs, including the first and third verses of "Some Kind of Wonderful" (1974).

In 2000, Brewer and Schacher added vocalist Max Carl, former Kiss guitarist Bruce Kulick and keyboardist Tim Cashion to the line-up.

Brewer played the bongo on Frank Zappa's song "Let Me Take You to the Beach" from the album Studio Tan, released in 1978.

In 2000, Brewer performed as a guest clinician at Modern Drummer Magazine's annual Drum Festival event.