With Ratt, Croucier wrote many of the band’s biggest hits such as “Lack of Communication” and “You’re in Love”. His backing vocals became a trademark part of Ratt’s sound. Croucier went on to own and operate a recording studio in Los Angeles called “The Cellar” where he recorded, produced and engineered hundreds of records for various bands and solo artists. He also formed a new band, Liquid Sunday a project based on his solo album of the same name.
Liquid Sunday played on the same bill for one show with Pearcy during the summer of 2006 and later formed a new band called Dirty Rats, consisting of Croucier on bass and lead vocals, Carlos Cavazo on guitar, and John Medina on drums.
Reportedly, the current line-up going by the name Dirty Rats features completely different musicians, ex- cept for Juan Croucier. Including guitarist from the band Love/Hate Jon E. Love and drummer from band Black and Blue Pete Holmes.
On May 12, 2012, Croucier reunited with RATT and performed with the band at the M3 Rock Festival for the first time since 1991.