I had to replace the rear cylinders in my 85 as well. Did not feel a bit of change in the pedal as it was only the left one actually leaking.
MOT showed no brake force on the rear left...

So the two circuits did what the should.

1973 2CV AK400 Ralley
1985 plus 4 four seater
1992 Peraves ecomobil
bicycles (pedersen to recumbent)