Abstract: Side arm for a vehicle seat may be pushed on or pulled off a mounting bracket attached to the frame of the seat without disturbing the upholstery of either the seat or the arm. The arm has three pins of different lengths which are pushed into three holes in the mounting bracket. The intermediate length pin is mounted near one end of a normally bowed spring plate so as to normally be axially skewed relative to the other pins. During assembly, a chamfered guiding surface on the lead end of the shortest pin engages the edge of a hole in the mounting bracket. As the short pin is pushed through the plate portion of the bracket, it initially forces the skewed pin to move relative to the arm so as to bend the spring and cause the skewed pin to become parallel to the other pins. After the skewed pin has passed through the plate the skewed pin returns under the force of the spring to its skewed position to retain the arm on the bracket.