Pressure plate problem

The best way to check it is with a feeler gauge between the disc and the pressure plate with the clutch pedal pushed to the floor. That way you can 100 percent ensure the disc is released or not. That is impossible with an explosion proof bellhousing. To work around this you could drill a hole in the bottom of the belhousing to prove this. It is possible the finger height of the pressure plate is wrong. This is likely what hays is going to do. There is a procedure in the old dirrect connection chassis manual on how to do this. I have always used McLeod pressure plates, if you can't get the hays one to release I would suggest a McLeod.