Altec Industries Inc. is recalling 120 2014 model-year Altec Aerial Devices equipped with counterbalance valves at risk for cracking, the National Highway Traffic Safety Administration reports.

SUN Hydraulics manufactured the faulty counterbalance valves last year, from April 1 to July 18. If they crack, hydraulic fluid may leak and lead to unintended boom movement. This poses a safety risk, NHTSA said.

Altec dealers will replace the counterbalance valves, free of charge. The recall is expected to begin on April 27.

Altec customer service can be reached at (800) 860-0183. Altec’s number for this recall is CSN 614.