Bad screen door rollers

Screen door was probably installed in the early seventies. The parts in question are the roller levelers on each corner of the door. The part is attached to the door by a vertical tab with a hole through which the screw that holds the corners of the door together passes. Below that screw is another screw which passes horizontally through the fixed body of the assembly then through the roller lever arm, a spring and then a nut. Tightening the screw nut assembly forces the lever arm to move the metal roller away from the horizontal door piece and on to the track. The whole assembly is about 2 1/2 in long, 9/16 in wide and 15/16 deep.The rollers are 7/8 inch in diameter and a 1/4 wide. The rollers are metal ball bearing. They run on "T"shaped tracks about 5 or 6 /32 wide at their widest. Smaller width rollers do not engage with the track. In our case the spring-adjusting nut-screw assembly either seized with rust then broke when adjusting was attempted.

Any help with sourcing new roller adjusters would be very appreciated