The LiftMaster K10-10203 Curved Door Arm, Medium Duty is a genuine OEM replacement component for commercial sectional door systems using LiftMaster medium-duty trolley operators. This curved linkage connects the door’s top bracket to the straight arm on the trolley, helping translate the operator’s travel into smooth, reliable opening and closing motion. It is designed for use on sectional overhead doors in light to medium commercial applications where a two-piece arm assembly is specified, and is commonly paired with the corresponding straight arm (sold separately) to complete the door arm set.
Use K10-10203 when refurbishing or repairing the linkage on compatible LiftMaster medium-duty trolley operators to correct issues like binding, uneven travel, or a bent arm. Installation typically involves fastening the curved arm to the door bracket and the straight arm, then verifying limit settings per the operator manual; after any arm replacement, travel limits should be checked and readjusted. For safety, disconnect power to the operator, ensure the door is properly balanced, and follow all LiftMaster service instructions or consult a qualified technician. Always confirm compatibility with your model’s parts diagram to ensure the correct medium-duty curved arm is selected.