The issue was the pedal only engaging about half way to the floor and sometimes not at all.After unsuccessfully trying to bleed the clutch hydraulic system using every conceivable method including reverse bleeding and pressure bleeding I removed the slave cylinder exterior "return spring"and got firm pedal immediately. What's the technical explanation for the spring's negative influence on the slave? I understand the TR6 did away with the outside return spring. The odd thing is I drove for 10 years with the TR6 trans that had that return spring in place???