Bruce Willis was set to reprise his role of Mr. Church, at a salary of three million dollars (750,000 dollars per day for four consecutive days). When he demanded one million dollars per day instead, Sylvester Stallone and the producers refused, and he left the film. Within three days, Stallone was able to get Harrison Ford to replace the Church role as a new character. Ford's "short notice" quip, as used in the trailer, alludes to these events (which were well publicized long before the film premiered).
Sylvester Stallone tried to get Wesley Snipes to play the role taken by Terry Crews in The Expendables (2010). Crews went on to play Hale Caesar after Snipes declined due to legal matters related to his tax-evasion charges that prevented him from leaving the United States without the court's permission. Wesley Snipes got the role as "Doc" shortly after his release from prison. In a scene, Dolph Lundgren's character asks Snipes' character what he was locked up for to which he replies "tax evasion".
When Toll Road (Randy Couture) asks Doc (Wesley Snipes) why he got locked up Doc replies: "Tax evasion". In 2008 Wesley Snipes was sentenced to three years in prison for tax evasion. He served from 2010 to 2013.
When he is asked about the whereabouts of Church (portrayed by Bruce Willis in the two previous films), Max Drummer (Harrison Ford) answers that "He's out of the picture". This is an in-joke about the fact that Willis' character was written out of the film and replaced with Ford's character.
In one scene, Antonio Banderas' character sings "El novio de la muerte" ("Bridegroom of Death"). That song is the official hymn of the Spanish Legion, an elite unit of the Spanish Army. Banderas was made an honorary member of that military unit in 2013.
In the first drafts of the screenplay Antonio Banderas' character is named "Matador" (Spanish for "killer"). After Banderas agreed to play the role, he made several suggestions for the character. One of them was to change his name to "Galgo" (Spanish for "greyhound").
After Mel Gibson was cast as Conrad Stonebanks, Director Patrick Hughes suggested the character have an Australian background. Although Gibson was born in the U.S., he spent most of his youth in Australia.
While trying to save Doc from the train, Christmas calls him a maniac. This is a slight reference to what Stallone's character, John Spartan, calls Snipes' character, Simon Phoenix, in Demolition Man (1993).
After the release of the film, Sylvester Stallone admitted the PG-13 was a mistake, saying "I believe it was a horrible miscalculation on everyone's part in trying to reach a wider audience, but in doing such, diminish the violence that the audience expects. I'm quite certain it won't happen again."
When Sylvester Stallone's and Harrison Ford's characters meet outside the airplane hangar, both are inside a car. The car is a Ford model, whose logotype is emphasized by the camera as nod to the actor.
Sylvester Stallone and Mel Gibson worked with Kurt Russell in the late 80s, with movies like Tequila Sunrise (1988) and Tango and Cash (1989), before they worked with each other. Kurt Russell was considered for the first one as Church, but turned the part down.
The helicopter of Conrad Stonebanks at the Somali port of Mogadishu, is actually a Eurocopter AS565 Panther, of the Bulgarian Air Force. Filming of the scene was done close to the 63rd Independent Maritime Helicopter Air Base at Varna, and the film crew used their aircraft. The green, red, and white roundel of the Bulgarian Air Force can be seen on the helicopter.
Sylvester Stallone and Antonio Banderas collaborated in three movies. In Assassins (1995), Stallone played the good guy and Banderas, the bad. In Spy Kids 3-D: Game Over (2003), their good guy and bad guy roles were reversed. Here, they are both good guys.
Doc (Wesley Snipes) refers to the dog tags of the fallen Expendables members, by the reference "jangle leg, jangle leg". This is a tribute to the late Bernie Mac's character from Life (1999) Jangle Leg. He even mimics the way Mac says his own name.
The Art Museum in Bucharest (called 'Muzeul de Arta Moderna Bucuresti'), where Stonebanks (Mel Gibson) meets Goran Vata (Robert Davi), is, in actuality, an office building: The Vertigo Business Tower in Sofia. The made-up art works, that are featured in these scenes, include a small replica of the famous "Endless Column" (1938) by Romanian sculptor Constantin Brancusi, a reference to Romania as the filming location.
Sylvester Stallone considered filling the void left by the Mr. Church character with a role originally intended for Charlie Sheen in the second film. The role was that of a C.I.A. operative pursuing Church. The role was ultimately removed from both scripts.
During the train sequence, the inscription "BDZh", in Cyrillic letters, can be seen briefly on one of the carriages. In Bulgarian, this is the abbreviation of "Bulgarian National Railways" company, a nod to the movie shooting location.
Arnold Schwarzenegger and Robert Davi co-starred in Raw Deal (1986). However, they both starred separately in the "Predator" franchise; Schwarzenegger in Predator (1987), and Davi in Predator 2 (1990).
After Barney rescues Doc, he reminds him that he was in a prison that should have been impossible to find. A similar prison was the main setting for Stallone and Schwarzenegger's previous film, Escape Plan (2013).
Wesley Snipes and Antonio Banderas also worked with Woody Harrelson and Ron Shelton in White Men Can't Jump (1992), and Play it to the Bone (1999). The closest they had together before this movie, was Play it to the Bone (1999), where Antonio and Woody had lead roles, and Wesley had a cameo role as himself. In this film, they have screentime together, which is also a good thing, since they played villains up against Stallone in Demolition Man (1993) and Assassins (1995).
Mel Gibson and Harrison Ford worked with Peter Weir twice, on Gallipoli (1981), The Year of Living Dangerously (1982), Witness (1985), and The Mosquito Coast (1986). They both had hit sequels written by Jeffrey Boam, Indiana Jones and the Last Crusade (1989), Lethal Weapon 2 (1989), and Lethal Weapon 3 (1992).
In this film, Mel Gibson's character uses the spin kick, which is an eastern martial arts move. The last time he used this move was in the original Lethal Weapon (1987). That film series was named after Gibson's Martin Riggs character because he was a supposed martial arts expert. His spin-kick was part of the story. By Lethal Weapon 4 (1998), this had been forgotten. When he went up the villain played by Jet Li he displayed none of these skills.
Victor Ortiz, a multiple welterweight boxing champion, doesn't throw a single punch (for the sake of defense or action sequences). Just before his character's shooting range demonstration, he's seen punching a hanging heavy bag with standard red leather boxing gloves, while Barney and Bonaparte first approach him on the DARPA base, nor does Jet Li, most renowned for martial arts, throw a punch, or perform a single kick in his brief appearance.
First movie that Mel Gibson and Harrison Ford have done together, but share no screentime. Both were considered for a lot of roles in big films, including Kevin Costner's roles in JFK (1991) and The Untouchables (1987).
Harrison Ford replaced Bruce Willis as the new Expendables C.I.A. contact Max Drummer. Ford, Mel Gibson, Sylvester Stallone, and Arnold Schwarzenegger were considered, and offered the role of John McClane in Die Hard (1988), but they all turned it down, due to being busy with films made the same year, and the role went to Bruce Willis.