It is not uncommon for a mechanic to have problems with the Teves brakes. They were short lived, something like 1986-1990, then Teves redsigned them and there was compitition from other companies. Even if you find a mechanic that worked on them back when they were new, we are now dealing with age problems, something that a new system would not have.
There is a reasonable amount of knowledge on this site to help with Teves problems.
You made a good move in keeping the old unit.
I suggest any 1988-1990 Reatta owner do a brake test every 6 months to check the system.
Go to
Reatta Data Page and read the brake test.