Green’s Dictionary of Slang

(US) a ranting preacher.

1939		FWP Guide MT 99: This followed a period of preaching in saloons, dance halls, and gambling houses, where roulette wheels, cards tables, and other paraphernalia were pushed aside to let the ‘brimstone busters’ hold forth [DARE].
1940		(con. 1820s) W.E. Wilson Wabash 224: An imitation of the new brimstone peddler at the Old Pigeon Hard-Shell Baptist Church.