The pro-Khalistani supporters had tried to slash the throat of the 78-year-old former Indian Army officer in a revenge attack on the streets of central London last year for his role in leading the operation to flush out extremists from the Sikh holy shrine of GoldenTemple in Amritsar.
Barjinder Singh Sangha and Dilbagh Singh were sentenced to 14 years in prison by Southwark Crown Court.
Mandeep Singh Sandhu will serve 10 years and six months in prison while Harjit Kaurand will serve a 11-year sentence.
They have to spend at least half the sentences in custody and can then be released on licence.
Sangha, 33, Sandhu, 34, Singh, 36 and Kaur, 38, were found guilty on July 31 following a trial by the same court.
Pronouncing the sentences, the judge said the "attack falls within the most serious category of wounding with intent" and took into account the "significant psychological harm caused to the Brars".
It is clear the attack was carried out in revenge for Brar's actions at the GoldenTemple, the judge said.
During the trial, the prosecution said Kaur had tracked Brar as he holidayed in London's West End with his wife Meena. She then passed on the Brars' whereabouts to the attackers.
Sangha, Sandhu and Singh were found guilty of carrying out the attack itself on September 30, 2012, and of wounding the general with intent.
Brar, giving evidence via videolink from India, said a pro-Khalistan website had declared him the "number one enemy of the Sikhs".
Another threat he said he received read: "There have been seven attempts on his life which have not succeeded, but the eighth one will." He was not protected on his trip to London, which he said was a private holiday.
Hundreds of Sikh men and women from across the UK gathered at the court for Tuesday’s hearing.