The old cases must be clean and free of oil.
SACHS clutch return general 
terms and  
summary.
BTS TURBO turbines return policy: 
See here.
EMITEC ADBLUE return policy: 
See here.
ALBONAIR ADBLUE return policy: 
See here.
ECOFIT ADBLUE return policy: 
See here.
Brake calipers return policy: 
See here.
WABCO return policy: 
See here.
KNORR-BREMSE return policy: 
See here.
REMA.GERMANY return policy: 
See here.
DPF DINEX return policy: 
See here.