The part the goes into the master cylinder should be the original VW part. Not sure what to call it. But it should be screwed into the front of the steel rod.
There should be almost no play at all.
The proper adjustment was to fit the rod into the master cylinder and attach it the the brake pedal. Then “unthread” the part that fits through the rubber piece into the master cylinder until there is zero play, then back it back in about a quarter to a half turn, just to make sure there is no pressure on the master cylinder.
Former Owner of a 1981 Classic Roadsters Ltd. Duchess (VW)
2005 Intermeccanica Roadster
If you own a TDr and are not in the Registry, please go to https://tdreplica.com/forums/topic/mg-td-replica-registry/ and register (you need to copy and paste the link)