Authorities say a merchant reported a silver Cadillac circling the block near Sixth Avenue and Broadway Street on Monday and alerted police.
When officers stopped the car, they found a hammer, gloves, a large canister of pepper spray and a pillow case.
The men, two adults and three minors, were arrested without incident. Jabril Greene, 24, and Makrice Leonard, 18, were booked for conspiracy to commit robbery, with bail set at $50,000. The names of the minors were not released.
There have been a series of smash-and-grab robberies at jewelry stores along Broadway, and investigators believed the crimes were being committed by crews of robbers from several South L.A. gangs.
According to the LAPD, two of the men arrested were verified gang members from a South L.A. Blood gang. Police say all of the suspects were wearing hooded sweatshirts despite it being a hot day.
One suspect had a bandaged hand, which police say could have been hurt in a previous smash-and-grab robbery.