Schwarze Industries is recalling 129 A7 Tornado, A8 Twister, A9 Monsoon, and M6 Avalanche street sweepers because they’re at risk for stopping unexpectedly, according to the National Highway Traffic Safety Administration.

The street sweepers at issue are in the 2013 to 2017 model years. The air brake systems on these vehicles may have been manufactured with the wrong fittings, causing the brake lines to leak air, NHTSA said. The condition makes the vehicles out of compliance with federal safety standards.

“If the brakes apply and the vehicle stops unexpectedly, it can increase the risk of a crash,” NHTSA noted on its website.

Schwarze dealers will replace the incompatible air brake line fittings, free of charge. The recall is expected to begin April 17. Street sweeper owners can reach Schwarze customer service at (800) 879-7933.