According to Jerry Mathers, who played Beaver Cleaver on the series, Bank suffered from various illnesses and was recently hospitalized in Rancho Mirage, Calif.
"Lumpy was the ultimate bully, but Frank was a very, very kind and gentle person and a very good actor to play it so well," Mathers said. "The show was about all the people you knew growing up and throughout your life, and Frank brought that perspective to the show."
After Beaver ended in 1963, Bank became a stock and bond broker in the 1970s and counted Mathers and his former co-star Barbara Billingsley, who played Mrs. Cleaver, among his clients. Bank reprised the role of Lumpy on the 1980s series The New Leave It to Beaver and in the 1983 TV movie Still Beaver. He also had a cameo as Frank in the 1997 movie Leave It to Beaver.
Bank released a memoir, Call Me Lumpy, in 1997, which garnered attention for a chapter detailing his "perpetual sexfest" during the '60s.
Bank is survived by his wife, Rebecca; daughters Julie Bank, Kelly Lightner, Michelle Randall and Joanne Littman; and five grandchildren.