The plastic inserts might be available from 80s diesel mercedes cars. Some research would be needed to determine which car had that size hardware.
I had a 83 300SD that needed an insert for the throttle linkage with similar ball ends like that and germanautoparts.com had inserts in stock.
I had a 83 300SD that needed an insert for the throttle linkage with similar ball ends like that and germanautoparts.com had inserts in stock.