Figure out if the MB a/c has R-12 or 134A freon, it is hard to find R-12 anymore and if you do it is very expensive. Hoses may look ok bu they go bad from the inside out, open the system since it is not charged and check the fluid...if it has black specks or is black at all hoses will need to be changed along with the compressor, condenser and evaporator...just got a quote for a 75 Pontiac to replace A/c...4 grand...could almost buy an aftermarket unit installed for that