An American musician and singer. He was an original member of Frank Zappa's Mothers of Invention, having previously been a founding member of The Soul Giants - the band from which the Mothers of Invention was formed. Estrada was the only member of the Mothers' original line-up to leave on his own in 1969 (the rest were fired).

He also played bass for Zappa's transitional 1976 Zoot Allures touring band, provided vocals and acting for Zappa's 1979 film Baby Snakes, as well as vocal work for the 1980's Zappa albums You Are What You Is, Ship Arriving Too Late to Save a Drowning Witch and The Man from Utopia.

As well as his work with Zappa, Estrada formed Little Feat with Lowell George in 1969. He also spent some years with Captain Beefheart & His Magic Band, from whom he was given the nickname Orejón ('big ears'). He was recruited into the Magic Band to supplement Mark Boston's bass playing and to allow Boston to play guitar for live shows. Estrada toured the US and Europe with the Magic Band in 1972 and 1973 and played on The Spotlight Kid and Clear Spot albums.