>>Sanden 508 style, will not work with my R-134a system?<<
The retrofit on your old system would have included changing/flushing out the old Mineral Oil. It should have been replaced with new Ester Oil.
The Summit listing says that 508 is supplied with PAG oil.
You MUST do a very, very thorough flush of the complete system to get rid of all traces of any old oil.
