An 86-year-old reputed Gambino wiseguy doing time for a murder he insists he didn’t commit is trying to get his conviction tossed — with a little help from Mafia turncoat Salvatore “Sammy the Bull” Gravano.

Frank “Frankie Loc” Locascio, a Gambino underboss during the reign of “Dapper Don” John Gotti, filed papers in Brooklyn federal court on Thursday to overturn his conviction for the 1990 slaying of purported mobster Louis DiBono in a World Trade Center parking garage.

Included in Locascio’s papers is a signed statement from Gravano, in which the infamous La Cosa Nostra snitch said that he neglected to tell prosecutors that Locascio was not involved with DiBono’s murder while testifying at trial.

Gravano’s statement came to light in November 2018 and on Wednesday, a federal appeals court in Manhattan issued an order allowing the statement to be admitted as new evidence in Locascio’s case.

“Frank Locascio had no role in the planning of, nor did he participate in any way in the murder or conspiracy to murder Louis DiBono,” The Bull’s statement reads.

Salvatore "Sammy the Bull
Salvatore “Sammy the Bull” Gravano appears in court in 2015.AP

In fact, the mob rat claims, Locascio tried to save DiBono’s life.

Gotti wanted DiBono dead because he kept failing to show up to meetings with Gotti. But in a recorded conversation from 1989, Locascio can be heard trying to calm Gotti down, assuring the skipper that DiBono would fork over $50,000 to make up for his absenteeism, the court papers state.

“Shortly after this conversation, Gotti told me that he strongly resented Locascio’s suggestion that he take the money and forget about killing DiBono,” Gravano’s statement reads.

Gravano said that Locascio’s failed attempt to spare DiBono’s life cost him his number-two spot in the Gambino crime family — Gravano said he was bumped up to underboss and Locascio was demoted to “acting consigliere.”

Both the US Attorney’s Office in Brooklyn and Locascio’s lawyer declined to comment on the filing.

Gotti died in 2003 in a Missouri prison.

Gravano confessed to being involved with 19 murders as part of his deal with the feds. He did a 15-year prison stint for dealing ecstasy and was released in 2017.