Green’s Dictionary of Slang

pulleys n.

(US black) braces (suspenders in US).

[US]D. Burley N.Y. Amsterdam News 7 June. 13: Them pulleys over my brace o’ broads will slay you dead.
[US] ‘Jiver’s Bible’ in D. Burley Orig. Hbk of Harlem Jive.